seventh framework programme -...

RESEARCH FOR THE BENEFIT OF SMEs

Grant Agreement Number: 605357 (FP7-SME-2013-1)

Project start date: October 2013

Project duration: 33 months

Seventh Framework Programme

Revalorization of wet olive pomace through polyphenol extraction

and subsequent steam gasification

This project has received funding from the European Union’s Seventh Framework Programme for research,

technological development and demonstration under grant agreement number 605357 (FP7-SME-2013-1)

DELIVERABLE REPORT

D4.3 Life Cycle Assessment of the PhenOLIVE process

Lead beneficiary:

Project Coordinator:

Dissemination level: PUBLIC

Version Prepared by Details Preparation date Period covered

V1.0 Joan Berzosa April 2016 M31-M33

V1.1 Leonardo Santiago June 2016 M31-M33 This document has been produced within the scope of the PHENOLIVE Project and is confidential to the Project’s participants. The utilisation and release of this document is subject to the conditions of the contract within the 7th Framework Programme, grant

agreement no. 605357

D4.3 Life Cycle Assessment of the PhenOLIVE process 2

ACRONYM LIST

Acronym Description

WOP Wet Olive Pomace

EOP Exhausted olive pomace

PEF Pulsed Electric Field

LCA Life Cycle Assessment

LCI Life Cycle Inventory

LCIA Life Cycle Impact Analysis

CC Climate change

OD Ozone depletion

FEU Freshwater eutrophication

MEU Marine eutrophication

FEC Freshwater ecotoxicity

MEC Marine ecotoxicity

WD Water depletion

DOW Description of Work document


REPORT CONTENTS

1 INTRODUCTION ............................................................................................................................................................ 4

1.1 OLIVE OIL PRODUCTION ........................................................................................................................................... 4

1.2 PHENOLIVE PROJECT ................................................................................................................................................ 6

1.3 ENVIRONMENTAL ISSUES ......................................................................................................................................... 8

2 LIFE CYCLE ASSESSMENT (LCA) ...................................................................................................................................... 9

2.1 METHODOLOGY ..................................................................................................................................................... 10

2.1.1 GOALS AND SCOPE DEFINITION ............................................................................................................... 10

2.1.2 LIFE CYCLE INVENTORY ANALYSIS ............................................................................................................ 13

2.1.3 LIFE CYCLE IMPACT ASSESSMENT ............................................................................................................. 15

2.1.4 LIFE CYCE INTERPRETATION ..................................................................................................................... 18

2.2 LIFE CYCLE ASSESSMENT IN POLYPHENOL EXTRACTION FROM OLIVE POMACE..................................................... 20

3 CASE STUDY. REVALORIZATION OF WET OLIVE POMACE THROUGH POLYPHENOL EXTRACTION AND STEAM

GASIFICATION (PHENOLIVE)............................................................................................................................................. 22

3.1 GOAL AND SCOPE DEFINITION ............................................................................................................................... 22

3.1.1 Goal of the study ...................................................................................................................................... 22

3.1.2 Scope of the study .................................................................................................................................... 22

3.2 LIFE CYCLE INVENTORY (LCI) ................................................................................................................................... 25

3.2.1 Data quality .............................................................................................................................................. 25

3.2.2 Assumptions ............................................................................................................................................. 27

3.2.3 Collecting data ......................................................................................................................................... 27

3.2.4 Calculating data ....................................................................................................................................... 27

3.3 LIFE CYCLE IMPACT ASSESSMENT (LCIA) ................................................................................................................. 27

3.3.1 Selection of impact categories, category indicators and characterization models .................................. 28

3.3.2 Optional elements .................................................................................................................................... 31

3.3.3 SimaPro .................................................................................................................................................... 31

4 RESULTS ..................................................................................................................................................................... 32

4.1 SCENARIO A ............................................................................................................................................................ 32

4.1.1 Scenario A assessment and suggested improvements ............................................................................. 38

4.2 SCENARIO B ............................................................................................................................................................ 39

4.2.1 Scenario description ................................................................................................................................. 39

4.2.2 Scenario B assessment and suggested improvements ............................................................................. 46

4.3 SCENARIO COMPARISON ........................................................................................................................................ 46

4.4 LIFE CYCLE INTERPRETATION .................................................................................................................................. 47

4.4.1 Evaluation of significant issues ................................................................................................................ 47

5 CONCLUSIONS ............................................................................................................................................................ 50

6. REFERENCES ................................................................................................................................................................. 51


1 INTRODUCTION

The present study aims at determining the environmental impacts linked to waste treatment plant of olive mill.

In the traditional olive oil mill, pulp and wastewaters are obtained as by-products and wastes. In the case of pulp

(wet olive pomace) after all oil extraction, is dried and burned in order to dry more pulp, or burned into a

cogeneration plant. In the case of wastewaters, has to be treated due to their high pollutant potential (high BOD

and COD, which contains especially risky organic compounds), but conventional processes are not able to remove

the required amount of pollutants, hence usually is used as fertilizer. Moreover, harvesting is one of the major

sources of contamination, being it is concentrated from November to March.

Additionally, some compounds which can damage the environment (polyphenolic compounds) have a big value

as prime matters in some markets, as cosmetics and food preservatives. These markets are expected to grow in

the next years, hence, it is an interesting by-product to be recover from the wet olive pomace (WOP).

Once the second extraction has ended and the WOP has been dried up, a different pulp is obtained (exhausted

olive pomace, EOP). The oil content of this pulp is very low and is not profitable keeping in the extraction being

delivered to waste management. This management uses it for co-generation, obtaining power and heat.

As an alternative, a gasification plant is planned to be used to obtain electrical power from WOP, once dried. The

process consists in reacting the fuel material at high temperatures with no combustion, using air and steam,

obtaining a syngas which can be burned obtaining power. The main reason of introducing this technology is to

increase the efficiency of the entire process. After lifespan of the plant, is planned to recycle as many materials

as possible.

The life cycle assessment carried out in during this period aims at quantifying the environmental performance of

the system, taking into account the whole life cycle in a cradle-to-grave study.

Since this document is public, some confidential information is not shown.

1.1 OLIVE OIL PRODUCTION

Olive (Oleae europeae) is an evergreen tree distributed all over the world, but 97% of the world production of

olive oil is located in the Mediterranean countries: Spain, Italy, Greece, Portugal, Tunisia and Morocco.

An olive consist basically in three parts: skin (epicarp), pulp (mesocarp), and the pit (endocarp). On solid basis,

most of the oil is in the pulp (75% of weight of the olive, contains 50% of oil), while the pit, which represents

about 23% of the weight, contains 1% of oil. Skin, which represents about 3% of the fruit weight, contains about

3% oil. Physical extraction methods are not able to extract all oil of the fruit, hence the solids contain up to 10%

of the oil.

Depending on the acidity of the oil, this can be classified in “Extra virgin olive oil” and “Virgin oil”. If the acidity is

decreased, the oil is called “refined olive oil”. In order to obtain a determined acidity value, these oils can be

mixed to obtain “olive oil”. When the oil have been extracted, the pomace is treated with solvents or by physical

means, (excluding re-esterification techniques and mixtures with other oils) and is called “Crude olive-pomace

oil”. This product can be refined, obtaining “Refined olive-pomace oil”, which has to have a determinate acidity

level. “Olive-pomace oil” is obtained by blending olive-pomace oil and virgin olive.

Olive harvesting is carried out either manually or aided with mechanical equipment such as shakers, electric

rakes, or pneumatic combs. To avoid the physical or biological deterioration of the olives, the industry is currently

following a main strategy of reducing the interval between harvesting and processing, aiming the process done


in less than 24 hours1. The next stage in oil production is transport to the mill, preventing damage. After a

separation of healthy and decayed fruits, the cleaning starts, and olives must be processed within 24-48 hour

after reception (storage period shall be minimum to avoid microorganism presence (fungus or yeast) can affect

the oil quality2.

Illustration 1. Olive parts (DOW PHENOLIVE)

Olive paste preparation is separated into two phases: fruit milling and paste malaxation. In the first process,

olives are crushed by metal mills or hammer mills. The second one, malaxation is the process in which the oil

drops liberated in milling are grouped, this one is performed by a thermomixer.

Next step is the solid-liquid separation to obtain the olive oil. For that purpose, the paste is loaded in a horizontal

centrifuge or decanter, where pomace is thrown in the opposite direction of the liquid outlets. These devices are

divided in 2 phase process, and 3 phase process, being this second one almost into disuse.

The WOP obtained from 2 phase mills is available now to be mixed with organic solvent, which can extract the

5-8% of oil still remaining. After this, pomace oil is enriched with virgin oil.

The current production of olive oil in Europe is around 2 million tonnes each season, carried out by around 10,000

olive mills in a sector comprising mainly of small and medium sized companies (olive producers, cooperatives,

olive oil mills, refiners, blenders and distributors) employing 800,000 people in the European Union 3,4. The EU is

the world leading olive oil producer and consumer (almost 80% of production5 and 75% of consumption

worldwide6. The production of olive oil is highly significant in Spain, Italy and Greece, and significant in Portugal,

France and Associate State Turkey. In terms of area, this activity represents 8-9% of agricultural land in Spain,

Italy and Portugal, and 20% in Greece7. More than 1.8 million agricultural holdings grow olive trees in EU, which

represents 40% of agricultural holdings in Spain and Italy, and 60% in Greece. The other side of this production

are more than 6 million of m3 Olive Mill Wastewaters (OMWW) and more than 7 million tonnes of solid waste

from pulp, husk and peels (WOP).


Table 1. Market of olive residues (DOW PHENOLIVE)

COUNTRY Number of olive mills

QUANTITY OF TONNES PER YEAR

Produced Olive oil Wet Pomace Dry pomace (With pits) Pit/stone

SPAIN 1,722 1,230,000 4,920,000 4,222,000 2,500,000

ITALY 6,000 721,418 2,606,271 1,211,916 n.a.

GREECE 2,500 352,000 n.a. 598,000 53,800-161,500

CROATIA 125 5,000 18,200 n.a. 3,640

SLOVENIA 12 275 1,100 n.a. 281

The more extended extraction technique in olive mills, 2-phase method, generates around 4 kilos of WOP residue

each kilo of olive oil produced. Thus, almost 8 million tonnes are generated in Europe each season, leading to

serious disposal problems due to the large space requirements. In addition, WOP contains a water content of 55-

65%, making it heavier and more difficult to transport. Transporting liquid effluents to long distances represents

environmental risks due to pollutant potential of WOP.

1.2 PHENOLIVE PROJECT

The consortium SMEs, being aware of the healthy components contained in some olive wastes (compounds

properties such as antioxidant, free radical scavenging, antimicrobial and anticarcinogenic activity of the

biophenols found in olive oil have been reported by several studies 8,9,10). They have developed the PHENOLIVE

technology in order to give a response to a growing market for such components, a solution that also has

additional benefits for olive oil chain SMEs in reducing disposal and environmental problems.

Natural antioxidants have a growing demand in emerging markets such as functional foods and food

preservatives. PBIO reported the polyphenols market was estimated at 77.88M€ in 200311, and at 120M€ in 2011.

Recent studies12 have forecasted a market of 290M€ in 2016. Currently, the market is captured by grapes, green

tea and red fruit. The olive oil polyphenols had 2% of market share in 2011, but it is growing ahead of the other

products due to their properties.

In a global scenario, functional foods market were estimated in 2011 at 2,300M€ expecting 8-9% of growing. The

main audience for these products are USA and Europe. Natural antioxidants also have a promising future as

natural preservatives in the food industry. The penetration of this product is estimated at 25% and is expected

to grow thanks to the new UE legislation, which are going to reduce the concentration of synthetic antioxidants.

The main polyphenols found in WOP are oleuropein, tyrosol and hydroxytyrosol. Hydroxytyrosol is considered

by the European market for polyphenols as the major component of the phenolic fraction of olive pomace, as

one of the few natural antioxidants that have been recognized for their antioxidants properties by the increasing

stringent regulations imposed by the European Food Safety Authority (EFSA) for functional foods13,14. These

factors, in addition with the remarkable properties of olive polyphenols as natural antioxidants with application

in food preservations, functional foods and cosmetics have encouraged different industry sector to invest in new

technologies to incorporate this compounds to their products.

In addition to the added value of polyphenol properties, olive oil mill waste remains a relatively energetic

potential, which means can be used as cheap fuel for using in mills to meet the heat and electricity needs, taking


into account this process reduces the amount of waste. In addition to the requirements of space these amounts

of waste requires, the further management and disposal of Olive Mill Waste (OMWW) represent the principal

problems, due to its pH value, fat content, organic content and high polyphenolic compounds content.

Furthermore, traditional methods of treating residues as fertilizer through field disposal are not yet effective due

to these wastewaters are not easily biodegradable15. Moreover, spreading wastewaters in soil is regulated by

law, determining the amount can be disposed by surface area, and takes into account the distance from inhabited

areas, height of groundwater and type of crops.

In order to overcome the environmental problem of OMWW management, some countries have been

developing technology to take profit of biomass heating potential. Several mills have designed thermal or electric

generation plants which uses WOP as fuel. Furthermore, the direct combustion concludes in a non-

environmental friendly and not optimized technology with low thermal efficiencies that waste high amount of

energy. But this option is not the optimal one because the WOP still has few interesting by-products remaining.

Regarding this added value products, a significant number of olive mills have chosen to dispose of the WOP giving

it (or selling) to Pomace Oil Extraction Plants (POEPs), where a chemical oil extraction takes place, obtaining a

lower quality oil.

On the other hand, considering the high content of polyphenols in WOP, their extraction prior to chemical

extraction of the remaining oil. This would provide extra benefits from polyphenol sales. The European Food

Safety Authority (EFSA) has supported the health benefits of hydrotyrosol supplements; the antioxidant capacity

of commercial olive extracts, especially this one, has proved to be much higher than other well-known

antioxidants.

The PHENOLIVE project aims at adding value to the olive mill activities: on one hand by obtaining polyphenols

from WOP. On the other hand, by investigating the potential of EOP to produce Syngas that would be used to

cover the energy needs to pomace oil extraction plants. For this purpose, some innovative technologies are being

used.

Firstly, the PHENOLIVE consortium has develop an extraction reactor based on Pulsed electric Filed (PEF)

technology to recover at least 50% of the polyphenolic compounds currently lost in WOP. The use of PEF

technology has several advantages over other extraction methods:

- Avoids activity of endogenous or added enzymes and thermal degradation.

- The temperature increasing is between 3 and 5 ºC, minimizing energy requirements and deterioration

of extracts16.

- High efficiency.

The purpose of this system is to break the cell membranes of organic soft tissue circulating through the

prototype. Thus, PHENOLIVE designs a system to induce irreversible electroporation of those cells in order to

facilitate the release of polyphenol molecules for its recovery.

Due to the fact that organic tissues contain mineral and water, the applied electric field results in high values of

instantaneous current and therefore large power being dissipated by Joule effect in the tissue. Just a few

microseconds of electric field are required to induce irreversible electroporation of cells. The energy

consumption keeps reasonably low, as well as the increase of local temperature in the tissue.

Also, the PHENOLIVE technology includes a gasification module which enables the conversion of a solid fuel into

electric power and heat.


The implementation of this process is driven by the high Low Heating Value (LHV), low percentage of humidity,

low content of sulphur and chlorines and high percentage of oxygen. Ash content is not critical due to the low

percentage in its composition. Among the various types of biomass appropriate for energy production, agro-

residues resulting as by-products of agricultural or agro-industrial activities are thought to be the most

important. Olive oil residue is regarded as one of the most promising agricultural residues suitable for energy

production 17. Compared with combustion, the energy efficiency in the case of gasification utilized in a combined

cycle mode is considered to be higher19. To achieve this objectives, an experimental pilot plant has been built in

order to extract polyphenols from WOP.

Regarding the gasification process, is motivated to obtain heat and electricity from the EOP from PHENOLIVE

plant, in order to cause the thermo-chemical conversion of biogenous feedstock.

Biomass have a considerable importance, as this feedstock constitutes the only source of the plant. After the

proper analysis of EOP as fuel, similar parameters to soft wood chips were shown, except high alkali, which was

determined as responsible of low ash softening temperature.

1.3 ENVIRONMENTAL ISSUES

The reduction of environmental impact associated with olive oil production is key relevance in the EU. Oil

extraction in European industry generates almost 8 million tonnes per year of WOP. The disposal of olive mill by-

products has become an increasing problem due different factors; First, the difficult degradation of polyphenolic

compounds causes that the disposal takes a long time to stabilize the waste. Secondly, the added water content

in WOP generated in 2 phase extraction process.

The Water Framework Directive 200/60EC deals with water management in the broad sense, and requires State

Members to take strategic and integrated management of all water resources. According this, waste should be

dealt with prevention, reuse, recycling and disposal, respectively in preference of treatment. Currently, waste

management practices causes environmental issues as soil contamination, underground seepage, water

pollution and foul odour emissions.

Traditionally, olive oil producer sector was composed by a big amount of independent producers very

disseminated; the low amount of wastewater production and the distance among the different producers allows

wastewaters were infiltrated in soil without arriving to rivers or phreatic level. But in Andalusia, in the 50s,

industrialization helped to create cooperatives and factories which helped to concentrate and increase

wastewater production. The late 70s, olive wastewater dumping was the main pollution problem in Guadalquivirs

basin19.

Olive mill wastewater is characterized by a high salinity, high organic content, suspended solids, mineral

elements, and a high content of biomass growth inhibitors20. The high content of organic matter and plant

nutrients (P, K, N, Ca, Mg and Fe) makes OMWW a cheap soil fertilizer, which, among other properties, causes

an increase of soil aggregation and stabilization21, and decrease pesticide mobility22. However, soil amendment

with this effluent must be carefully controlled to avoid potential adverse effects on soil and water23.

Untreated olive wastewaters are a major ecological issue for olive producing countries due to low pH, high COD

(up to 110 g/l) and high biological demand (BOD up to 170 g/l) 24. Conventional treatments are not enough to

purify WOP wastewaters due to the presence of polyphenol, which is a very resilient compound. 19. Also,

extensive investigations have focused on the change of salinity, pH and hydraulic conductivity, and on the

accumulation of phytotoxic polyphenolic compounds inhibiting soil microbial activity23: The irrigation of olive

groves with olive mill wastewater increases the water hydrophobic behaviour of the topsoil, due to the


accumulation of organic matter and a decrease in hydraulic conductivity and infiltration rate. Hydrophobicity

deteriorates the soils ability to conserve water, affecting the plants water supply. These three factors may

increase surface runoff and thus faster soil erosion. In addition, OMWW application increased flux heterogeneity

with the generation of preferential pathways, increasing the risk of groundwater contamination21.

Direct discharge of olive mill wastewater into fresh water reduces its oxygen availability due to the organic matter

presence, which upsets the entire balance of the ecosystem. Moreover, the high concentration of reduced sugars

may stimulate microbial respiration, thus further lowering dissolved oxygen concentration. If discharged into

waters with high phosphorus contents, can lead to eutrophication, thus hypoxia24. Its accumulations can affect

surface water because abnormally dark polyphenol concentration may colour natural waters 20. Furthermore,

lipids from OMWW form a layer on the surface of the receiving water blocking sunlight and oxygen exchange

with the atmosphere25. In the case of marine systems, direct OMWW disposal might induce pre-pathological

alterations 26.

In the case of OMWW, if is stored or discharged in open areas (land or water), fermentation processes can take

place23. As a product, methane, hydrogen sulphide and other gases can be emitted. Regarding these, both have

a big climate change generation potential.

2 LIFE CYCLE ASSESSMENT (LCA)

The growing importance of environmental protection and potential impacts related to the products (in its use

and fabrication phases) has increased the interest to develop new methodologies to offset this depletion. One

of these methodologies is Life Cycle Assessment (LCA) 27.

LCA allows to improve some parts of a process of the life cycle of a product or service, as identifying opportunities

to improve the environmental performance during their life cycle. LCA is an important tool to inform decision-

makers at different levels (industry, government, or non-government organizations). Furthermore, this

methodology is useful for improving environmental performance and measurement techniques. Considering its

results, LCA can be used in marketing purposes, trough ecolabelling, environmental claiming, and environmental

product declaration 27.

This methodology identifies and quantifies the environmental aspects and potential impacts throughout a

product life cycle, from raw material to final disposal, considering in this process transportation, use and recycling

in case of cradle to grave studies. In case of cradle to gate, gate to gate, or gate to cradle, life cycle is made from

and until the interesting stages 27.

In LCA studies there are four phases:

a) Goal and scope.

b) Life cycle inventory.

c) Life cycle impact assessment.

d) Life cycle interpretation.

The first term, goal and scope definition is the phase in which the LCA is planned and its definition will determine

how depth and extensiveness of the study will be carried out. LCA studies are iterative projects, since any phase

can modify partially or totally the study approach if it would be necessary.

The second phase, life cycle inventory (LCI) is an inventory of the entire system, with determined boundaries

from the previous phase. In it are recorded all input and output data regarding the considered system.


The third phase is the life cycle impact assessment (LCIA). This stage is thought to provide information about LCI

and calculations about environmental impacts caused in the studied system.

Finally, life cycle interpretation provide the results of LCI, LCIA or both. This results are discussed in order to extract conclusions oriented to goal and scope. All phases of the study can be revised in illustration 2.

2.1 METHODOLOGY

Illustration 2. LCA process (ISO 14040:2006)

2.1.1 GOALS AND SCOPE DEFINITION

The goal and scope on an LCA must be clearly defined and must be constant during all the intended application,

except due to the iterative nature of LCA studies, should be modified 28.

Goals and scope, including system boundaries and level of detail depends of the subject and the intended use of

the study 27.

2.1.1.1 Goal of the study

The goal of an LCA states the intended application, reasons for carrying out the study, intended audience, and

determine whether results are intended to be used in a comparative study or in disclosed study 27.


2.1.1.2 Scope of the study

The scope has to be able to define the entire study and to be compatible with the selected goal. Scope includes

the following items 27:

- Product system to be studied

- Function of the system

- Functional unit

- System boundary

- Allocation procedures

- LCIA methodology and types of impacts

- Interpretation to be used

- Data requirements

- Assumptions

- Value choices

Function and functional unit

The function of the system shows the aim of the studied system, its objective and what is designed for. In the

case of functional unit, quantifies the identified functions to take as a reference unit. This reference is necessary

to ensure comparability of LCA results, particularly critical when different systems are being assessed, to ensure

that comparisons are made on a common basis 27.

The functional unit must be consistent with the goal and scope of the study. In fact, one of the purposes of a

functional unit is to provide a reference to which the input and output data are normalized. Must be clearly

defined and measurable 28.

Reference flows shall be defined. Comparisons between systems shall be made based in the same function or

functions, quantified by the same functional unit or units in the form of their reference flows. I any additional

function or system is not taken into account, the omission may be explained in the document 28.

System boundaries

System boundaries determine the limits of the studied system, always in concordance with the proposed goal

and scope. The selection of the system boundary must be consistent with the goal of the study. Detail level also

have to be explained, in addition to the system boundaries criteria selection 28.

The choice of elements of physical system to be modelled depends on the goal and scope of the study, its

application and audience, assumptions made, data constraints, and cut-off criteria. Models used, assumptions

and cut-off criteria should be clearly understood and described 27.

Not including stages, processes, inputs or outputs within study boundaries is allowed if does not significant

change the overall conclusions of the study. This decisions shall be explained 28.

Cut-off criteria shall be clearly described. The effect on the outcome of the study of the cut-off criteria selected

shall also be assessed and described. In this phase important inputs or outputs shall not be omitted. For this

purpose, in addition to mass, is important to consider energy and environmental significance 28:


- Mass: require the inclusion in the study of inputs which contribute to mass input or output.

- Energy: consist in the same criterion, using energy units, and fuels involved.

- Environmental significance: decisions on cut-off criteria should include inputs that contribute more than

an additional defined amount of the estimated quantity of individual data of the product system that are

specially selected because of environmental relevance.

When setting the system boundary, several stages, processes and flows should be taken into account, for

example 27:

- Acquisition of raw materials.

- Inputs and outputs in the main manufacturing process.

- Transportation.

- Production and usage of fuels, electricity and heat.

- Use and maintenance of products.

- Recovery of used products (reuse, recycling and energy recovery).

- Manufacture of ancillary materials.

- Manufacture, maintenance and decommissioning of capital equivalent.

- Additional operations, as lighting and heating.

Allocation

In the case of a multi-product system, environmental performance has to be divided in order to obtain which

impacts are caused by each product. This allocation can be based in mass, volume, economic or other units.

The study shall identify shared processes shared with other product systems and deal with them according to

the stepwise procedure 28:

1. Allocation should be avoided dividing the unit process to be allocated in sub-processes. Then each sub

process should have their inventory. If not possible, system should be expanded to include all functions

related with co-products, taking into account the system boundaries

2. If allocation cannot be avoided, inputs and outputs should be partitioned according the co-products

importance in a way that reflects the physical relationships between them (normally mass or volume).

3. Where physical relationships cannot be established, the inputs should be allocated between the products

and functions in a way that reflects other relationships between them, for example, economic value of

the products.

Data quality

Characteristics of data recovery and sources has to be shown in order to satisfy the stated requirements. In this

chapter characteristics of the data has to be specified.


Data quality requirements should address the following data 28:

- Time-related coverage

- Geographical coverage

- Technology coverage

- Representativeness

- Consistency

- Reproducibility

- Sources of data

- Uncertainty of the information (models and assumptions)

All data selected for an LCA study depend on the goal of the study, such data may be collected from the

production site or be obtained or calculated from other sources 28.

Assumptions

If any information regarding system (data, process, material, production scheme…) is assumed, simplified or

taken as a value choice, it has to be explained and motivated in the LCA report.

2.1.2 LIFE CYCLE INVENTORY ANALYSIS

LCI phase is a review of input and output data of the studied system. It involves data collection to meet the goals

of the study 27. It also involves data collection and calculation procedures to quantify relevant inputs and outputs

of the system 27.

This phase is an iterative process, when data is being collected and more is learned about the system and new

data requirements or limitations might be identified. Thus, changes in the data collection procedure can be

required hence that the goals of the study are still be met 27.

2.1.2.1 Collecting data

Quantitative and qualitative data must be collected for each process unit within the system boundaries. To avoid

misunderstanding risk (i.e. double counting), a description of each unit must be recorded 28. Illustration 3 shows

how data shall be collected.

Data for each process unit must include 27:

- Products, co-products and waste.

- Emissions to air, discharges to water and soil.

- Other environmental aspects

- Flow diagrams

- Describing each unit process in respective detail to influencing inputs and outputs.

- Energy inputs, raw material inputs, ancillary inputs, and all physical inputs.

- Describing data collection and calculation techniques


Illustration 3. Collecting data procedure (ISO 14044:2006)

2.1.2.2 Calculating data

All calculation procedures must be documented and the assumptions shall be clearly stated and explained.

Calculation procedures should be consistently applied throughout the study 28.

Following data collection, calculation procedures, including 27:

- Validation of data collected: Checking data collection to confirm and provide evidence the data quality

requirements for the intended application have been fulfilled.

- Relating of data to unit processes.

- Relating of data to the reference flow of the functional unit: An appropriate flow shall be determined for

each unit of the process in relation to functional unit.

The calculations of energy flows should take into account all kind of fuels and electricity sources used, efficiency

of conversion and distribution of energy flow, as well as the inputs and outputs associated with the generation

and use of that energy flow.


2.1.3 LIFE CYCLE IMPACT ASSESSMENT

LCIA has to evaluate if environmental impacts generated in the process can be considered as significant, taking

into account LCI data and considering preselected impact categories. LCIA phase aims at providing information

to assess the system LCI results, and understanding the environmental performance. In general, this process

involves associating inventory data with specific environmental impact categories and category indicators,

thereby attempting to understand and quantify these impacts. Even the LCIA phase can be an iterative process

for reviewing the goal and scope of LCA study to determine if the objectives of the study have been met, or to

modify the goal and scope if are not possible to achieve 27.

Transparency is a critical point to the impact assessment to ensure the assumptions are clearly described and

reported, since choice, modelling and evaluation can introduce subjectivity 27.

Illustration 4 shows the different steps to assess LCIA phase.

Illustration 4. Elements of LCIA phase (ISO 14040:2006)

According to the LCIA objectives, methodologies can be midpoint or endpoint. In the first one, methodology tries

to quantify the environmental damage in an intermediate point between emission point and receiving

environment. In the second one, endpoint methodology refers to direct damage to the environment.

2.1.3.1 Selection of impact categories, category indicators and characterization models.

The selection of impact categories must be justified in goal and scope of the LCA. This phase shall reflect

environmental issues of the system, taking the goal and the scope in consideration. The model used for choosing

impact categories must be also explained and described 28.

Characterization models reflect the environmental mechanism by describing the relationship between the LCI

results, category indicators and, in some cases, category endpoints. These characterization models are used to


derive the characterization factors. The environmental mechanism consist in the total of environmental

processes related to the characterization of the impacts 28.

Illustration 5 Category indicators (ISO 14044:2006)

For each category impact, the necessary components of the LCIA include 28:

- Identification of the category endpoint (if considered)

- Definition of the category indicator for each category endpoint or endpoints

- Identification of appropriate LCI results can be assigned to the impact category

- Identification of characterization model

Depending in the goal and scope and the environmental mechanism, spatial and temporal characterization

should be considered 28.

The environmental relevance should be clearly stated, including some items, such the ability of the category

indicator to represent the environmental relevance and reflect consequences of the LCI results, and

environmental data to the characterization model with respect to the category endpoints (condition of the

category endpoint, relative magnitude of assessed change in category endpoint, spatial and temporal scale,

reversibility of environmental mechanism and uncertainly of linkages between category indicators and category

endpoints) 28.

2.1.3.2 Assignment of LCI results (classification)

Consist in the LCI result distribution among the selected category impacts, in such a way that harmful effects for

environment are determined and grouped in the category impacts in which are generated; in other words,

categories are matched with contaminants or actions caused.

This assignment can be exclusive to one impact category or more than one.


2.1.3.3 Calculation of category indicator results (characterization)

Consist in the assignation of the obtained data in classification stage to each impact category. Thus, each

pollutant or action which cause an impact, has a numerical factor. This factor multiplies to output/input amount.

In this way, each impact category is quantified in comparable units. This numerical factors depends on the

characterization methodology: endpoint or midpoint.

If LCI results are unavailable or if data are of insufficient quality for the LCIA to achieve goals and scope, either

an iterative data collection or an adjustment of goal and scope is required 28.

Depending on the validity and characteristics of the characterization models and factors, the results can be useful

or not. Simplifying assumptions may vary depending impact categories and geographical region.

The existing factors for each category impact can influence the overall accuracy on the LCA because of some

factors like complexity of environmental mechanisms between system and the category endpoint, endpoint or

midpoint methodology (generally, more close to endpoint, less accuracy) spatial and temporal characteristics,

and dose-response characteristics 28.

2.1.3.4 Optional elements

With non-mandatory character, some elements and information can be introduced in LCA study depending on

the goals and scope. These elements are 28:

- Normalization: Converting all impact categories to the same units to be compared.

- Grouping: sorting and ranking of impact categories

- Weighting: convert and aggregating indicator results across impact categories using numerical factors

based on value-choices, prior to weighting.

- Data quality analysis: a better understanding of the collection of indicator results.

Their optional character is given by the high uncertainly generated.

Normalization

Normalization consists in the dimensionless results for making comparable all impact categories, obtaining a total

impact amount. The aim of normalization is to understand better the relative magnitude for each indicator result

of the production system under study. May be helpful in 28:

- Checking for inconsistencies

- Providing and communicating information on the relative significance

- Preparing for additional optional procedures

Calculations for obtaining normalization parameters consist in the division of indicators by a reference value.

This value can be the total inputs and outputs for a given spatial area (global, regional, national or local), for a

given area on a per capita basis, or a baseline scenario, such an alternative product system 28.

Grouping

Consist in the assignment of impact categories into one or more sets as goals and scope defines. May involve

sorting and/or ranking. Has two possible procedures 28:

- Sort the impact categories on a nominal basis (e. g. by characteristics such as inputs and outputs or global

regional and local spatial scales

- Rank the impact categories in a given hierarchy (e.g. high, medium and low priority).


Ranking is based on value-choices, hence organizations, societies and different individuals may have different

preferences 28.

Weighting

Weighting is the process of converting indicator results of different impact categories by using numerical factors

based on value-choices. It may include aggregation of the weighted indicator results. Has two possible

procedures 28:

- To convert the indicator results or normalized results with selected weight factors

- To aggregate these converted indicator results or normalized results across impact categories

This step is based on value-choices, not in scientifically based, hence organizations, societies and different

individuals may have different preferences. In an LCA study is desirable to use several weighting factors and

methods, conducting a sensitivity analysis to assess different results 28.

Data quality analysis

Some additional techniques may be useful or needed to understand better the significance, uncertainly and

sensitivity of LCIA results in order to 28:

- To help distinguish if there are significant differences in the results

- To identify negligible LCI results

- To guide an iterative LCIA process

The specific techniques are 28:

- Gravity analysis: Statistical procedure that identifies those data having the greatest contribution to the

results.

- Uncertainly analysis: Procedure to determine how uncertainties in data and assumptions progress and

how they affect the results of the LCA.

- Sensitivity analysis: Procedure to determine how changes in data and methodological choices affects the

results.

According to iterative nature of LCA, data quality may lead to revision of LCI phase.

2.1.4 LIFE CYCE INTERPRETATION

The last stage of LCA study is the result of LCI and LCIA interpretation. In this stage, conclusions can be drawn

according the results and also considering recommendations in the same way to goal and scope.

This phase comprises several elements as shown in illustration 6, as follows:

- Identification of significant issues based in LCI and LCIA phases

- Evaluation that considers completeness, sensitivity and consistency checks

- Conclusions, limitations and recommendations


Illustration 6. Relationship between elements within the interpretation phase with the other phases of LCA (ISO14044:2006)

The interpretation have to consider in relation to the goal of the study 28:

- The appropriateness of the definitions of the system functions, functional unit and system boundaries

- Limitations identified by the data quality assessment and the sensitivity analysis.

It is important to know that LCI results refers to input and output data not to environmental impacts. In addition,

uncertainly is introduced in LCI results due to the compounded effects of input uncertainties and data variability.

2.1.4.1 Identification of significant issues

This stage is useful to structure the results from the LCI and LCIA phases in order to determine the significant

issues in accordance to the goal and scope definition. The purpose of this phase is to include implications of

methods used, assumptions made, etc., in the preceding phases (allocation rules, cut-off decisions, selection of

impact categories, category indicators and models) 28.

Some significant issues are:

- Inventory data (energy, emissions, discharges, waste…)

- Impact categories (resource usage, climate change …)

- Significant contributions from life cycle stages to LCI or LCIA results (individual unit processes or groups

of processes such transportation or energy production)


2.1.4.2 Evaluation

The objectives of the evaluation element are to establish and enhance confidence and reliability of the results of

the LCA and LCI study, including the significant issues identified in the first element of the interpretation. During

the evaluation, the use of the following three techniques shall be considered 28:

- Completeness check

- Sensitivity check

- Consistency check

Completeness check

The objective of the completeness check is to ensure all relevant information and data needed for the

interpretation are available and complete. If some information is missing or incomplete, should be completed or

introduced for satisfying the goal and scope of LCA study. If this missing or incomplete information is considered

necessary for setting significant issues, the previous phases (LCI and LCIA) should be revised or goal and scope

should be adjusted 28.

Sensitivity check

The objective of sensitivity check is to assess the reliability of the final conclusions by determining how they are

affected by uncertainties in the data, allocation methods or calculation of category indicator results, etc. It shall

include the conclusions extracted from the sensitivity and uncertainly analysis if performed in previous phases28.

In this phase, considerations shall be given to 28:

- Issues predetermined by the goal and scope of the study

- Results from all other phases of the study

- Expert judgements and previous experiences.

In this way, the output of the sensitivity check determines the need of more extensive or precise sensitivity

analysis

Consistency check

The objective of consistency check is to determine whether the assumptions, methods and data are consistent

with the goal and scope. In this phase, the following questions should be known as relevant in the LCA or LCI 28:

a) Are there differences in data quality along a product system life cycle and between different product

systems consistent with the goal and scope of the study?

b) Have regional and/or temporal differences, if any, been consistently applied?

c) Have allocation rules and system boundary been consistently applied to all product systems?

d) Have the elements of impact assessment been consistently applied?

2.2 LIFE CYCLE ASSESSMENT IN POLYPHENOL EXTRACTION FROM OLIVE POMACE

Olive and olive oil production are widely studied for different purposes. This is due to the fact that it is a

traditional activity which nowadays keeps being profitable, since the product is very extended and appreciated

in cuisine, mainly in Mediterranean regions.

In this case, a multipurpose revision has been carried out: on one hand, the extraction of polyphenols using

innovative methods, mainly in olive oil production. On the other hand, environmental performance studies in


olive oil production. Furthermore, gasification application will also be revised. This division shall be done, due to

its very hard to find a similar study in which those three topics are considered.

In the first term, there is quite studies about polyphenol extraction from different plants, part of the plants and

methods. In the last years, several technologies are raising with the aim of achieving more efficient, cheaper and

faster processes. Obtaining by-products are a plus and in some cases, a must. In order to manage the potential

environmental impact and to have a valuable product, some novel green technologies are able to treat olive mill

wastewater with centrifugation, batch evaporation and drowning-out crystallization-based separation process

and extract polyphenols with ethanol29. Polyphenols can also be extracted from other parts of the olive, for

instance, the leaves by using ethanol 30. Another technique used to extract polyphenols and other by-product

chemicals is by means of PEF (Pulsed Electric Field), which improve the extraction rate with no negative effects31.

On the other hand, environmental performance is getting more and more important in industrial processes. The

aim of the majority of the studies is to reduce pollutants and obtain more and more quantities of by-products.

In the case of olive oil production, a lot of studies are made in Mediterranean areas in which production is very

high, and try to reduce greenhouse gas emissions 32. The aim of those studies is to identify which processes are

more harmful to the environment, propose changes in production system and new technologies. For that, LCA is

a powerful tool which can show in which stage a process is more pollutant, why, and how to improve this

performance. LCA is a useful methodology in the decision-making process 33. When the process is analysed stage

by stage, as a general rule agricultural production is the highest in GHG emissions, due to the non-renewable

energy use and nitrogen and potassium fertilizer usage 34.

In the third term, the steam gasification process is another way of revalorization. The aim of this process is to

profit olive pomace and obtain steam and electricity in feed-in and selling regime of this electricity. After some

options, previsions point to be an interesting profitability values 35.

After a review of projects, it can be observed that there is no research in which all subjects (polyphenol extraction

in olive oil production, gasification and life cycle assessment) are combined. Hence, this study has the added

value of being the first one to combine these three topics in order to improve the proposed process.


3 CASE STUDY. REVALORIZATION OF WET OLIVE POMACE THROUGH POLYPHENOL

EXTRACTION AND STEAM GASIFICATION (PHENOLIVE).

3.1 GOAL AND SCOPE DEFINITION

3.1.1 Goal of the study

This study is aimed at assessing the environmental performance of the PHENOLIVE project considering different

modifications in the process.

Hence, it is intended to determine which are the hotspots of the process, including an analysis of raw material

collection, equipment manufacture, use and end-of life phases together with associated energy and

transportation requirements. In essence, the LCA will examine every stage of the entire process. From the

procurement of raw materials, through its manufacture, distribution, use (and possible reuse or recycling) and

final disposal. It will collect the inputs (resources) and the outputs (emissions) of each phase, both will be

aggregated in the life cycle and then converted in the corresponding potential impacts to the environment. This

is why this study can be rated as “Cradle to grave”.

The identification of these hotspots allows to determine which activities or processes contributes more to the

environmental damages. When those items are known, modifying the system can avoid or reduce the impacts

generated, improving the environmental performance of the system.

The modifications are organized in chapters called “Scenarios”, thus these can be compared in order to know if

the modifications can actually achieve the expected results. In order to compare the environmental performance

of the system in different configurations, for this study is planned to have two scenarios; the first one takes into

account the PHENOLIVE plant and the implementation of a co-generation waste treatment plant for the purpose

of obtaining heat and power, as it is used in most of treatment facilities of WOP. The second scenario consists in

the implementation of a gasification plant instead of co-generation as waste treatment.

This way, each waste treatment method can be analysed to know what higher impacts are and in which stage of

the entire process are generated. At the end of this study it will be possible to compare between the two waste

treatment systems taking into account environmental units and determine which is environmentally better.

Target audience is any person which is interested in PHENOLIVE project, hence that results can be revised by

anyone.

3.1.2 Scope of the study

3.1.2.1 Function and functional unit

As mentioned before, the aim of PHENOLIVE project is to treat wastes of olive oil manufacturing companies

avoiding environmental issues of that activity, and obtaining polyphenolic compounds as by-product from these

wastes.

The International ISO 14044 standard defines a functional unit as “Quantified performance of a product system

for use as a reference unit” 28.

Taking into account that the functional unit has to be consistent in reference to the function of the system, in

this case the selected functional unit will be “1kg of WOP treatment in PHENOLIVE plant”.

3.1.2.2 System boundaries


In system boundaries chapter the organization of the system has to be explained, since which processes are

inside the study and which are out, explaining criteria for the decision.

In this chapter, an initial base scenario has been be considered. Later, in the corresponding chapter,

modifications will be considered to be comparable, obtaining different environmental performances.

For this study, the system is divided into subsystems in order to be as accurate as possible in the inventory and

system boundaries. The first subsystem called “pilot plant” regards the PHENOLIVE pilot plant, taking into

account inputs, outputs, transportation, transformation within the system and its disposal as a waste. The second

subsystem considers treatment of wastes generated in the PHENOLIVE plant process and its refurbishment. As

the first scenario weighs co-generation, it will be included in the system boundaries until second scenario will be

studied.

For this purpose, the first step in pilot plant subsystem is considering the structure of the plant and its production,

which has been included in the system, distinguishing among the different materials.

Transportation of each device has taken into account, due to the dissemination of the origin of the devices. Some

of them came from abroad, hence the transportation stage becomes important. In the case of the transportation

of system prime matter, WOP, it will be generated in the same place where the plant is. Data inventory of this

scenario considers the materials of the plant and it transportation in “plant construction” module.

Regarding consumption inputs, electrical ones have to be taken into account in PHENOLIVE plant. Despite in co-

generation plants the generation of electric power cover the consumption, in this case the facilities are far of

treatment point, hence the electrical output is not recirculated to PHENOLIVE plant. Consumption of chemical

reagents are within the system (ethanol and water). At the exit of the prototype, the product of this subsystem

is polyphenolic compounds and WOP wastes, which drying is within the system.

Concerning the waste scenario, materials composing are PHENOLIVE pilot plant has been taken into account as

recyclable wastes, when possible. For non-recyclable materials, a standard treatment has been considered.

The second subsystem concerns waste management coming from PHENOLIVE pilot plant. Since it is done in

external facilities and belongs to traditional management, the structure will not be taken into account. Heat and

electricity are produced; Electricity is injected to the electric grid and heat is distributed to industrial and building

heating. Illustration 7 represents the system flowchart.


CO-GEN

PROTOTYPE EXTRACT

PRODUCTS

EMISSIONS

WASTES

INPUTS

HEAT

ELECTRICITY

PILOT PLANT SUBSYSTEM

COGENERATION SUBSYSTEM

Raw materials and fuels

Polyphenols, electricity and heat

Emissions to air, soil and water

Wastes to treatment

Polyphenol extraction

prototype

INPUTS WASTES

PRODUCTS

EMISSION

S

PROTOTYPE

EXTRACT

CO-GEN

ELECTRICITY

HEAT

Cogeneration

Electricity power production

Heat production Polyphenol extract

Illustration 7. Diagram of scenario A


3.1.2.3 Allocation

In multiproduct systems, in order to assign the proportional part of the environmental impacts to all outputs, the

allocation procedure determines the ratio to every flow of product.

According to ISO 14040 and 14044 standards, allocation should be avoided separating the different process

which creates different products. When this is not possible, a system expansion should be applied. If it was not

possible again, a physical sharing must reflect the importance of each product within the system (mass or

volume). If the physical characteristics of the flows are not comparable, another kind of relationships has to be

reflected.

If it is not a common multiproduct systems that can be split into subsystems to avoid allocation issues, an

alternative way is required, since, without this allocation, all environmental impacts would be attributed to the

main product. Thus, a separation of the environmental costs is needed.

In this case, products are polyphenols, electricity and heat produced; since a mass allocation is not possible and

the final purpose of these products is to be sold, an economic allocation allows to reflect the importance of each

profitable output within the system. Taking into account the prize of each product, the allocation of

environmental impacts is shown in table 3. In the case of electricity and heat production, for the first 15 years

the price for kWh varies to next years.

After applying market prices for each product, allocation results are shown in table 2:

Table 2. Allocation

Production/k

g WOP Allocation

(%)

Polyphenols (g) 8.008 96.288

Electricity power (kwh) 0.639 1.577

Heat (kwh) 0.865 2.135

3.2 LIFE CYCLE INVENTORY (LCI)

Life cycle inventory analysis aims at including the information and calculation processes needed to quantify input

and output flows27. Inputs contains matter and energy necessary to carry the activity, while outputs covers

products, matter, emissions to water, soil and water, and energy. To consider the data confidence, data quality

must be shown, referencing the origin27.

For this study, ECOINVENT© database has been used in processes which has not been created from measured

data in proper facilities.

3.2.1 Data quality

The quality of the data is determined by the multiplication of the three factors. Respectively, these express

temporal, geographic and technological affinity. Lower results indicate better quality of the data and higher

values means less accurate data. These factors are applied to the processes which constitutes the criteria of the

values are described in table 3. In other words, these three factors are assigned to the ECOINVENT © processes

selected:


Table 3. Data quality reference.

INDICATOR TEMPORAL GEOGRAPHICAL TECHNOLOGICAL

1

Less than 3 years of

difference with the year of

the study.

Data from study area. Data from the same factory/process/material.

2 Less than 6 years. Average data from a wide region. Data from processes and materials under study

from another companies or industries.

3 Less than 10 years. Data from a similar production

conditions.

Data from processes and materials under study

with different technology.

4 Less than 15 years. Data from an area with few

similarities.

Similar process or material data, with the same

technology.

5 Unknown data age or more

than 15 years.

Data from an unknown area or

with absolutely different

conditions.

Data from similar processes and materials, with

different technology.

Regarding the structure of the plant, most of the components has been directly weighted, separating each

material. Those which not, the weight has been estimated using 3D design software or taking information from

technical datasheets. The represented transportation regards the distance between the plant placement and the

dealer location. The assigned values for data quality are represented by order of Temporal-geographical-

technological and total. After all values, 12 is a median value which indicates an average data quality.

Finally, the obtained products are shown in table 4. These final outputs are quantified for the expected lifespan

of the plant. The polyphenol rate production has been taken from the operating regime of the PHENOLIVE pilot

plant.

Table 4. Product amounts

PRODUCTION/kgWOP

Polyphenols (g) 8.008

Electric power (kwh) 0.639

Heat (kwh) 0.865


3.2.2 Assumptions

In order to simplify some processes which can excessively enlarge the study or caused by lack of data, in life cycle

assessment studies is common to assume some data or processes.

In this study has been taken some assumptions

- Not all EOP is used in cogeneration facilities, there is a fraction which not.

- Transportation of EOP from PHENOLIVE pilot plant to cogeneration plant has been considered within the

boundaries of the system. Way back has been taken into account, but has not been considered in other

transports, like ethanol, because the uncertainty of the delivery lorry schedule.

- Ethanol tanks are reused for three months before being replaced.

- Due to uncertain placement of ethanol dealer and his consistency in time, has been supposed this

material comes from a dealer placed in Toledo, 35 km away from the plant location. Regarding wastes,

has been supposed that dealer is in charge to recycle the tanks, anyway within the system.

- It is assumed the temperature of WOP before the drying process is 25ºC.

- At the end of life stage, is supposed that as many materials as possible are recycled. Other wastes cannot

be recycled, and are delivered to other treatment.

- About the surplus of heat generated in cogeneration and gasification, a mixed usage between residential

and industrial has been considered.

- In gasification construction plant, buildings has not been considered in the inventory due to the actual

placement has buildings in which the plant can be placed. In addition to this, gasification plant is

considered to be in the same place that PHENOLIVE prototype.

3.2.3 Collecting data

In the case of this study, the collected data has had different dimensions: on one hand, measured data consist

mainly in the weighted materials regarding the PHENOLIVE pilot plant. In addition, ethanol and water used in the

process, polyphenol quantity generated and electricity consumption are measured data too.

On the other hand, some bibliographic data of the inventory has been taken from different sources. From initial

studies of PHENOLIVE project the minimal efficiency of polyphenol extraction (50%) and price, and low heating

value of EOP and initial moisture was obtained from Technische Universität Wien.

In addition, bibliographic sources used in calculating data have been energetic efficiency of cogeneration in

electricity and heat production39. The price of generated kWh has been taken from Royal Decree 661/200740

3.2.4 Calculating data

One of the calculation procedures is obtaining some material weights of the PHENOLIVE pilot plant, taking into

account the whole weight of a stage and obtaining other weights by differences.

3.3 LIFE CYCLE IMPACT ASSESSMENT (LCIA)

The aim of LCIA chapter is to quantify the environmental potential impacts associating inventory data to the

selected impact categories and their indicators27. This part consists in 4 phases, three of them are mandatory

(selection of impact categories, classification and characterization). In the case of the fourth phase (normalization

and optional elements), results are obtained using normalization factors: these values are taken from the used

database during the calculation. The purpose of this factors is to make comparable the results of the different

environmental impacts calculated during characterization (each one has their units: i.e. kg of CO2 eq., kg P eq. or

kg N eq., among other units). For this purpose average data is used in order to determine normalization factors.


Due to this data is not very accurate, normalization introduces high uncertainty to the study. Hence,

normalization phase and subsequent non-mandatory sections will not be carried out in this study.

For the calculation of the LCIA, factor emissions of ECOINVENT© database have been considered.

The objective of this study is to determine 4 parameters:

- Climate change

- Energy consumption

- Wastes production

- Consumption of water.

This goals can be divided into two categories: on one hand, those which can be obtained from inventory data

(energy consumption, waste production and water consumption). By other hand, climate change, which have to

be calculated using SimaPro software developed by Pré consultants (https://www.pre-

sustainability.com/simapro) and Life Cycle Assessment methodology. Using this second way, more impacts has

been determined in order to have a better perspective of impacts on water, not just its depletion: Freshwater

and marine eutrophication, freshwater and marine ecotoxicity, and water depletion. In addition, Ozone

depletion has been included in the results, due the growing aware about ozone layer status since years ago.

3.3.1 Selection of impact categories, category indicators and characterization models

According ISO 14040, an impact category is the class representing environmental issues of concern to which life

cycle inventory analysis results may be assigned.

For this study, some minimum results are expected to cover: Climate change (CC, kg CO2 eq), energy consumption

(EC, MJ), freshwater consumption (FC, m3), and total waste production (TWP, kg). Three last of those results (EC,

FC, and TW) are information can be obtained from LCI, hence some related impacts will be added: Freshwater

eutrophication (FE), Marine eutrophication (ME) and ozone depletion (OD).

For the calculation of impacts, ReCipe Midpoint Hierachist (H) method has been used. Regarding spatial

characteristics, Europe data has been selected. In processes which has more detailed information, Spanish data

has been taken into account. In temporal characteristics, it has been taken the whole lifespan of the PHENOLIVE

plant, 20 years.

As ISO 14044:2006 requires, the necessary component for selection of the impacts of LCIA are shown in table 5:

https://www.pre-sustainability.com/simapro



Table 5. Environmental mechanism. (Recipe, 2008. A life cycle impact assessment method which comprises harmonised category indicators at the midpoint and the endpoint level. First edition (v 1.08). Report I: Characterization. May 2013

revision 41)

IMPACT

CATEGORY LCI RESULT

CHARACTERIZATION

MODEL CATEGORY INDICATOR

CATEGORY

INDICATOR RESULT

CC Climate change Amount of GHG emissions Global warming

potential

Infrared radiative forcing

(w.yr/m2) Kg CO2 eq to air

EC Energy

consumption Consumed energy - - MJ

FC Freshwater

consumption Consumed water - - m3

TWP Total waste

production Generated wastes - - kg

OD Ozone depletion Ozone depletion substances:

CFC’s, HCFC’s, HALONS, etc…

Ozone depletion

potential

Stratospheric ozone

concentration (ppt.yr) kg CFC eq (to air)

FE Freshwater

eutrophication

Eutrophying substances: P

compounds

Freshwater

eutrophication

potential

Phosphorus

concentration (kg.yr/m3) kg P eq. (to water)

ME Marine

eutrophication

Eutrophying substances: N

compounds

Marine

eutrophication

potential

Nitrogen concentration

(kg.yr/m3) kg N eq. (to water)

FET Freshwater

ecotoxicity

Human toxic and ecotoxic

substances

Freshwater

ecotoxicity potential

Hazard-weighted

concentration

Kg of 14DCB (to

freshwater)

MET Marine ecotoxicity Human toxic and ecotoxic

substances

Marine ecotoxicity

potential

Hazard-weighted

concentration

Kg of 14DCB (to

marine water)

WD Water depletion Freshwater use Water depletion

potential Amount of water m3 (water)

3.3.1.1 Climate change

Climate change is a global impact caused by the greenhouse effect. Its rising is provoked by the increasing of

determinate gases in the atmosphere, mainly carbon dioxide. Other relevant GHG gases are methane and nitrous

oxide, which have a higher global warming potential than carbon dioxide, but its emissions uses to be much lower

than CO2 42

Those gases which most are generated in fossil fuel combustion, contribute to form layers in the atmosphere

which retains heat, causing the rise of atmospheric temperature and all kinds of effects in the ecosystems and

human health.42

In life cycle assessment and carbon footprint studies, in order to compare the contribution of these different

gases to the impact are measured, estimated or calculated in kg CO2 equivalent.42


3.3.1.2 Energy consumption

Energy consumption regards all energetic inputs that enters the system. Indeed, this is included in this chapter

because is one of the objectives of the study, but properly is not an environmental impact. This value will be

measured in MJ consumption during whole life cycle considered in the system.

3.3.1.3 Freshwater consumption

The same that previous chapter, freshwater consumption is not an impact properly, hence the data will be

included in results chapter because is one of the main objectives of the study. The final amount will be presented

in m3.

3.3.1.4 Total waste production

As energy and freshwater consumption, waste production is neither an environmental impact itself, hence the

results will be a LCI compilation. Will be presented in kg.

3.3.1.5 Ozone depletion

Ozone destruction in the stratosphere is a natural process caused by sunlight and chemical reactions, and is

compensated by its formation during the same processes. Thus, the depletion of ozone layer takes place when

the destruction rate is higher than regeneration rate. This increase is mainly caused by fugitive losses to the

atmosphere of anthropogenic substances which persist in the atmosphere. Stratospheric ozone (90% of ozone

in the atmosphere) prevents UV radiation to reach the earth surface, thereby leading to ecosystem and human

health problems. This is why ozone layer is vital for life43.

The chlorofluorocarbons (CFC) have a recalcitrant character and contain chlorine and bromine atoms, which are

very effective in degrading ozone due to heterogeneous catalysis, causing a slow depletion of stratospheric ozone

around the globe. In addition, chlorine and bromine atoms have the ability to destroy a large amount of ozone

molecules because they act as free radical catalyst44.

Ozone layer depletion (ODP) is defined as a relative measure of capacity of ozone depletion substances, using

CFC-11 (trichlorofluoromethane) as a reference. In LCIA, the ODP is used through equivalency factors after the

characterization of different ODSs at the midpoint level 42

3.3.1.6 Eutrophication

Eutrophication takes place when nutrients are gathered in aquatic ecosystems allowing the proliferation of

vegetal organisms, which exhaust the dissolved oxygen42

Characterization of this impact uses to take into account only those nutrients which limits the yield of aquatic

biomass. The natural nitrogen and phosphorus cycle is the mainly source of P and N, thus the growth of

phytoplankton depends on the availability of these elements. In industrial and agricultural regions, natural inputs

of N and P are exceed by far41.

For nitrogen, LCA methodology measures the effects with units of kg of N equivalent per kg of emission in the

case of marine eutrophication. It has three main effects: i) Vegetal communities change, predominating

nitrophilous species over less nitrophilous ones, not so common. ii) Nitrogen presence modifies soil equilibrium,

and can provoke damages on vegetal species. iii) The surplus of nitrogen in nitrate form can infiltrate trough soil,

enabling water reservoir pollution, raising nitrate levels in drinking water, leading to diseases, especially in

children45.


In the case of phosphorus, the used unit is kg of P equivalent per kg of emission in the case of freshwater

eutrophication. The effect of phosphorus is an excessive algae and superior plant grow. When it dies, the

microbial degradation consumes the majority of dissolved oxygen45.

3.3.1.7 Ecotoxicity

Some compounds can affect to animal and vegetal species, even humans, which can be calculated if endpoint

method is used. Ecotoxicity impact category tries to determine the effects of pollutants in different phases. In

this case, the presences of those pollutants will be analysed in marine and freshwater.

3.3.1.8 Water depletion

In many parts of the world, water is a scarce resource, but in other parts is an abundant resource. Extracting

water in dry areas can provoke big environmental damages, even human health damages. There is no functional

global market due to transport costs are too high.41

3.3.2 Optional elements

For this study, due to the uncertainly of normalization factors, this chapter will not be included.

3.3.3 SimaPro

SimaPro (https://www.pre-sustainability.com/simapro) is a professional tool for the calculation of

environmental, social and economic impacts linked to a product or service all along its whole life cycle. This

characteristics brings the opportunity for carry out calculations to a big amount of methodologies, as ecodesign,

ecolabelling, carbon footprint and hydric footprint, for example. Some of the more used applications of SimaPro

are:

- Improvement opportunities through identification of significant environmental yield during a process.

- Assessment of contribution of determinate stages to global environmental affection, aiming to improve

new products and services.

The software package disposes of scientist databases of materials and processes (ECOINVENT ©

(http://www.ecoinvent.org) or European Platform of Life Cycle Database (http://eplca.jrc.ec.europa.eu), among

other).

In addition, the software relies on the main calculation methodologies of impact assessment, like ReCipe,

(http://www.lcia-recipe.net), Impact 2002+ (http://www.quantis-intl.com/impact2002.php) and Ecoindicator 99

(http://www.pre-sustainability.com).


http://www.ecoinvent.org/

http://eplca.jrc.ec.europa.eu/

http://www.lcia-recipe.net/

http://www.quantis-intl.com/impact2002.php

http://www.pre-sustainability.com/


4 RESULTS

4.1 SCENARIO A

Bellow these lines the results for the first scenario are shown. In this chapter, two subsystems has been

considered: the first one concerns to PHENOLIVE pilot plant, taking into account the materials production,

operational input and outputs needs, transportations, and end of life. The second subsystem within the

boundaries is a cogeneration waste treatment process.

Regarding allocation procedures, economical system has been applied due to products are obtained with the aim

of being sold, in addition to the inability to make a comparison between mass and energy units. As a result, 96%

of the impact are allocated to polyphenol production, 1.5% to electricity production, and 2% to heat production.

As a last reminder, the obtained results are calculated in reference to 1 kg of WOP treatment (functional unit),

during which 8.008g of polyphenol are obtained. In table 6, the obtained results are shown, while illustration 8

shows them graphically:

Table 6. Scenario A results

UNIT Value

Energy consumption* MW 215

Waste production* kg 26,895

Water used* m3 1,758

Climate change** kg CO2 eq 2.80

Ozone depletion** kg CFC-11 eq 6.43*10-8

Freshwater eutrophication** kg P eq 1.69*10-3

Marine eutrophication** kg N eq 3.33*10-4

Freshwater ecotoxicity** kg 1,4-DB eq 0.027

Marine ecotoxicity** kg 1,4-DB eq 0.022

Water depletion** m3 0.0306

*: Results referred to whole lifespan

**: Results referred to functional unit (Treatment of 1kg of WOP)


Illustration 8. Scenario A results.

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40.

60.

80.

100.

Climate change Ozone depletionFreshwater

eutrophicationMarine

eutrophicationFreshwaterecotoxicity Marine ecotoxicity Water depletion

Scenario A. Treatment of 1kg of WOP.

A. Phenolive structure B.1. Phenolive Plant operation B.2. Phenolive Pilot plant waste management

D. WOP transport C.1. Co-gen. PHENOLIVE Electricity, low voltage {ES}| market for | Alloc Def, U

Heat, district or industrial, other than natural gas {


In illustration 8, the impact categories are represented in columns and different processes of the system are

depicted by different colours grouped in columns. The height of each colour in each column means the

contribution in percentage to the impact which refers to.

Processes above 0% represent a contribution to the impact categories, due to the processes which refers

corresponding colour cause that impact (i.e. the production of materials of PHENOLIVE prototype cause around

5% of the whole climate change of the whole scenario). In the case of processes below 0%, means that concrete

processes cause an avoided product. Avoided product are alternative ways to produce something avoiding

traditional production methods and its impact (i.e. waste management of materials of PHENOLIVE prototype

avoids a 10% of climate change impact due to it consist in recycling instead landfill disposal. If landfill disposal is

implemented instead recycling, the impact would be above 0%).

From illustration 8 some ideas can be taken. First of all, the main contribution to impact categories are caused

by the production of material of the prototype and by the materials of the prototype functioning regime.

Prototype structure (PHENOLIVE Structure) represents lower impacts in every impact category, but it can be

considered as significant except in climate change and water depletion. Other activities, like emissions of the

cogeneration process (purple, Co-gen PHENOLIVE) not affect significantly any impact category, being responsible

of 5% of marine eutrophication as leading cogeneration emission impact. At second place, there are an avoided

product caused mainly by waste management of materials of the prototype. Another process which contributes

to this results are electricity production at cogeneration facilities, (which avoids burning natural gas and hard

coal), and a minor extent, heat production.

If this avoided product is investigated, the amount of avoiding pollutant emissions can be determined, as well as

the process which cause it. The almost majority of the avoided product of climate change is caused by evaded

carbon dioxide emissions to air due to hard coal mining has not been carried out to generate that energy. For

ozone depletion, 98% of emissions avoided is composed by methane, during petroleum production for waste

management, while pollutants non-emitted during electricity production are caused by uranium avoided

production. Avoided phosphate emissions to water are caused by averting mining activity to extract hard coal in

freshwater eutrophication, while in the case of marine eutrophication, non-emitted nitrates in water and NOx to

air are caused by the same mining processes. For ecotoxiticy categories, avoiding copper emissions to water is

responsible of avoiding impacts. This is caused by treatment of redmuds in bauxite production in case of waste

management, and by copper scrap treatment in electricity production. For water depletion impact, the evaded

activity which is not carried out to save that water is the production of decarbonised water production.

Regarding plant operation materials, it is analysed with proper accuracy taking them separately. In illustration 9

results are shown.

It can be seen that ethanol production causes a high percentage of contribution in every category. In the case of

climate change, carbon dioxide is the main pollutant emitted, as well as methane is for ozone depletion. In the

same way, nitrate emissions to water and nitrogen oxides to air causes freshwater and marine eutrophication

respectively. Copper emissions are responsible for marine and freshwater ecotoxicity, while ethylene production

causes part of the water depletion impact.


Illustration 9. Plant operation results

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Plant operation

Ethanol, without water, in 99.7% solution state, from ethylene {GLO}| market for | Alloc Def, U Tap water {RoW}| market for | Alloc Def, U E. Ethanol transport


Another important process from the scenario A is PHENOLIVE pilot plant production materials. As done with

plant operation, these materials can be analysed, as shown in Illustration 10.

One of the most pollutant processes of the prototype component is the production of ethanol tank.

As the previous analysis, carbon dioxide to air is the main emitted pollutant in climate change category, caused

mainly by plastic production. An important part of ozone depletion is caused by methane emissions to air, mainly

by treatment structures. In the case of freshwater eutrophication the impact has an equitable distribution of

30%, approximately among ethanol tanks, PEF chamber, and electronic component production. Phosphate

emissions to water are responsible of the affection, mainly in mining operations. Nitrate emissions to water are

the main pollutant which causes eutrophication, which are mainly generated by ethanol tank production. Both

ecotoxicity impacts are caused by copper emissions to water during mining activities in the production of PEF,

electronic component and ethanol tank, and regarding water depletion, plastic extrusion causes 90%.


Illustration 10. Plant structure results.

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Plant structure

A.1. pilot plant A.1.1. TK-1A.1.2.TK-2 A.1.3.TK-3A.1.5.TK-5 A.1.4.TK-4A.1.6.TK-6 A.1.7.TK-7A.1.8.TK-8 A.1.9.PEFElectronic component, active, unspecified {GLO}| market for | Alloc Def, U PumpsUltrafiltration module {GLO}| market for | Alloc Def, U A.1.10.bag filterA.1.11.Valve Electronics, for control units {GLO}| market for | Alloc Def, UA.1.12.Pipes Transport, freight, lorry, unspecified {GLO}| market for | Alloc Def, U


With the purpose to check if all important impacts has been mentioned, an analysis of identification of significant

issues has been carried out. This method allows to determine which the strongest impacts are, and in this case

will be used to ensure that all important affections has been said in the above lines.

To calculate the importance, a table has been built, in which rows are represented environmental impacts

(climate change, ozone depletion…) and in the columns, the processes of the project are represented

(PHENOLIVE structure, PHENOLIVE plant operation…). For each environmental impact, the contribution in

percentage has been calculated. This percentage is referred to each impact, which means that for example,

cogeneration has a contribution between 0 and 10% to climate change, but not climate change is 10% of the

cogeneration impacts. Then, this value has been rated with words and colours, as can be seen in table 7.

Table 7. Identification of significant issues.

PHENOLIVE

STRUCTURE

PHENOLIVE PLANT

OPERATION

WASTE

MANAGEMENT

WOP

TRANSPORT COGENERATION

ELECTRICITY

PRODUCTION

HEAT

PRODUCTION

CC C G B C C B B

OD F G B C C A B

FEU E F B C C B B

MEU E F B C D B B

FEC F F B C C A B

MEC F F B C C A B

WD D G B C C B B

G >100%

F 50-100%

E 25-50%

D 10-25%

C 0-10%

B 0- -50%

A <-50%

It can be observed that the processes generating higher impacts are the PHENOLIVE plant operation and

structure respectively. In addition, WOP transport and cogeneration have lower impacts in comparison with

higher ones. On the other hand, waste management, electricity production, and heat production, as said before,

have positive impacts due to the avoided product generated. In the case of waste management, landfill disposal

is avoided; and for heat and electricity production, hard coal and natural gas burning are avoided.

4.1.1 Scenario A assessment and suggested improvements

After obtaining results during previous chapter, some changes would improve the environmental performance

of Scenario A.

In the first term, regarding plant operation goods, the biggest impacts are caused by the ethanol production.

Consequently, in order to reduce the affection of this product, the amount of ethanol should be reduced. This

modification need to be tested in the pilot plant, because the polyphenol extraction performance would be

modified, and this would change in turn the allocation percentages. Another way to reduce the ethanol usage is

to replace it with another substance which can develop the same solvent function, but with a lower


environmental impact. Hence, this alternative way would require more research even the first one. Nevertheless,

in order to reduce the environmental effects of the ethanol, more research is needed.

Secondly, regarding the prototype structure, the modules which more effect are the ethanol tanks, due to, as

said, the required amount them. Despite the fact that the tanks are reused for three months, the generated

impact is quite big, hence a more sustainable solution would be installing a bigger deposit for ethanol storage,

allowing to reduce the amount of plastic and aluminium.

4.2 SCENARIO B

4.2.1 Scenario description

For scenario B, the whole PHENOLIVE project will be implemented in the Life Cycle Assessment, since gasification

is proposed as a waste treatment method for this chapter. All process for PHENOLIVE prototype are the same,

while cogeneration has been removed from the system. As well as the first scenario, some assumptions have

been considered. In this line, the location of the gasification plant has been considered in the same place that

PHENOLIVE pilot plant.

The modifications of the system are shown in illustration 11.

Illustration 11. Diagram of scenario B.

GAS

PROTOTYPE EXTRACT

PRODUCTS

EMISSIONS

WASTES

INPUTS

HEAT

ELECTRICITY

PILOT PLANT SUBSYSTEM

COGENERATION SUBSYSTEM

Raw materials and fuels

Polyphenols, electricity and heat

Emissions to air, soil and water

Wastes to treatment

Polyphenol extraction

prototype

INPUTS WASTES

PRODUCTS

EMISSION

S

PROTOTYPE

EXTRACT

GAS

ELECTRICITY

HEAT

Gasification

Electricity power

production

Heat production Polyphenol extract


The data used in this scenario has been given by the manufacturer of gasification plant. This information is based

on an industrial scale plant and it has been recalculated applying a corrective factor.

The new data in the inventory regarding the structure of gasification pilot plant structure, operation regime, and

waste generated after its whole lifespan. An important modification is since gasification plant is located in the

same place than PHENOLIVE pilot plant, the electricity produced can be used during this process. In addition,

produced heat can be used in drying stage, and transportation is removed.

In the case of products, polyphenol performance remains the same, due to the fact that there is no modification

in the polyphenol extraction method. Otherwise, in the energy production, the number is different. The total

amount is shown in table 8. Since the production changes, at least energy production, allocation will be modified

due the higher performance of gasification in comparison to cogeneration. This provokes the allocation of

polyphenol production to be lower, that way, the impacts are expected to be lower independently of the

modifications of the system.

Table 8. Scenario B products and allocation.

PRODUCTION/ kg WOP Allocation percetage

Polyphenols (g) 8.008 69.51

Electric power (kwh) 10.54 8.88

Heat (kwh) 16.17 21.61

As the first scenario, an average of data quality has been made, obtaining a value of 4, taking the same reference

than the previous scenario.

After considering changes for scenario B, table 9 shows the results for each impact.

Table 9. Scenario B results

UNIT Value

Energy consumption* MW -12,795

Waste production* kg 378,100

Water used* m3 2,360

Climate change** kg CO2 eq -4.48

Ozone depletion** kg CFC-11 eq -7.64*10-7

Freshwater eutrophication** kg P eq -7.73*10-4

Marine eutrophication** kg N eq -1.05*10-3

Freshwater ecotoxicity** kg 1,4-DB eq -0.166

Marine ecotoxicity** kg 1,4-DB eq -0.146

Water depletion** m3 -0.047

*: Results referred to whole lifespan

**: Results referred to functional unit (Treatment of 1kg of WOP)

4.3 Life Cycle Assessment of the PhenOLIVE process 42

As in scenario A, illustration 12 is a representation has to be shown in order to determine which the processes

are with more affection to the selected impact categories.

In this scenario there are some similarities and some difference regarding first one. In the case of the things that

there have not a big change, the avoided products are generated by recycling as waste management, and energy

production. By other hand, some differences can be found; first, there are more avoided impacts, caused mainly

by the gasification implementation, because in the waste management system the amount of energy produced,

both electricity and heat, are higher than cogeneration process. Another important difference is the contribution

of important processes like PHENOLIVE pilot plant operation and structure has decreased at every impact

category despite having the same numbers: this is caused by the higher avoided impact of gasification plant.

As PHENOLIVE structure and pilot plant operation processes were analysed in the previous scenario, this time

will not be done again because are the same data. The analysis of data will be conducted in order to determine

which the origin of avoided impacts is.

If gasification avoided product is analysed, the contribution to the avoided impact of heat and electricity

production will be determined, since with illustration 12 is not possible to discern which energy is the main cause

of avoiding environmental impacts. With this purpose, illustration 13 represents gasification plant operation

process.


Illustration 12. Scenario B results

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Scenario B. Treatment of 1 kg of WOP

A. Phenolive structure B.1. Phenolive Plant operation B.2. Phenolive Pilot plant waste management F. Gasification Structure B.3. Gasification Plant operation


Illustration 13. Gasification plant results

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Comparison of scenarios

Heat, district or industrial, other than natural gas {RER}| market group for | Alloc Def, U Electricity, low voltage {ES}| market for | Alloc Def, U

Limestone, crushed, washed {GLO}| market for | Alloc Def, U Solvent, organic {GLO}| market for | Alloc Def, U

Tap water {RoW}| market for | Alloc Def, U B.3. Gasification Plant operation


Looking at illustration 13, some conclusions can be extracted. Firstly, there are not only avoided impacts:

gasification emissions during functioning cause almost 10% of climate change and marine eutrophication, which

in comparison to 100% of avoided product, is not representative. The same way to solvent production, which

generates 10% of ozone depletion.

Moving on to avoided impacts, in the first four impacts the contribution for electricity and heat production are

approximately equivalent, while for both ecotoxicity impacts electricity leads 90% of avoiding impact.

Regarding climate change the avoided energy obtained from coal allows to save the consequent carbon dioxide

emissions. For ozone depletion gasification allows not to emit ethane to air, preventing uranium production in

electricity production and methane from petroleum production for heat. Phosphate emissions to water are

responsible of freshwater eutrophication: In both electricity and heat production the missing mining stage causes

the avoided impact. This evaded mining allow to save nitrogen oxides emissions to air, which makes marine

eutrophication an evaded impact. For both ecotoxicity categories, the non-emitted copper to water during

mining activities are causative of better results for gasification. Finally, heat production by gasification methods

makes 75% of water savings during heat production, while in the electricity generation process, production and

supply of decarbonised water allow to avoid 25% of water depletion impact.

Table 10. Scenario B identification of significant issues

PHENOLIVE STRUCTURE

PHENOLIVE PLANT OPERATION

WASTE MANAGEMENT

GASIFICATION STRUCTURE

GASIFICATION OPERATION

GASIFICATION WASTE MANAGEMENT

CC C F B C A C

OD C C B C A B

FEU F G B C A B

MEU C D B C A B

FEC C C B C A B

MEC D C B C A B

WD C F B C A B

G >100%

F 50-100%

E 25-50%

D 10-25%

C 0-10%

B 0- -50%

A <-50%

Regarding significant issues analysis, as the previous scenario, has been carried out to determine which higher

impact processes are, as represented in table 10. This time, the PHENOLIVE structure and pilot plant operation

have lower contributions to studied environmental impacts, but, anyway both processes have the higher

contributions to studied environmental impacts.

In case of gasification operation, despite the gasification air emissions are included in this chapter, generated

energy has higher avoided impacts than impacts generated by atmospheric emissions.


4.2.2 Scenario B assessment and suggested improvements

After analysing results coming from second scenario, some aspects can be mentioned; Firstly, the effects

generated by common parts, as PHENOLIVE pilot plant and PHENOLIVE plant operation, are exactly the same

(the total amount of pollutants emitted during the production of its materials), but the contribution to the

impacts are lower. This is caused by the lower allocation to polyphenols; from 95% in scenario A comes to 69%.

This means while in the first scenario, 95% of emitted pollutants were responsibility of polyphenolic compound

extraction, in the second scenario was 69%. Despite in the scenario B the total amount of pollutants emitted is

higher (more wastes to treat, more infrastructures, more chemical reagents) having a lower allocation to

polyphenol extraction results in lower emissions in reference to the functional unit. The modification of the

allocation rules are caused by higher amount of produced electricity and heat.

Regarding suggested improvements, some modifications could be implemented to increase the environmental

performance of the system. First of all, as one of the impacts of gasification plant operation is atmospheric

emissions, a reduction of emissions are welcome in order to reduce environmental impacts. In this case, since

emissions has been calculated by emission factors from bibliography and not from pilot plant, is not determined

the technical possibilities to reduce atmospheric emissions. Secondly, other process which contributes to some

impacts is the production of the organic solvent, hence replacing this chemical reagent by any other with lower

impacts, or reducing his usage, could help to have a higher environmental performance. In addition, the

reduction of ethanol usage is also a way to minimize environmental impacts.

4.3 SCENARIO COMPARISON

As said before, the second scenario has a better environmental performance, mainly due to the higher amount

of obtained products, in concrete heat and electricity. In the case of results with values bellow 0 (only in scenario

B) means that the system avoids the emission of more pollutants than it emits. Never has to be read as a sink

due to this system does not consume pollutants, simply avoids the processes which issues a higher amount.

In illustration 14 both scenarios are compared in order to determine the difference between them beyond

numbers.

Illustration 14 Scenario A vs. B comparisons

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1

2

3

4

kg CO2 eq mg CFC-11 eq g P eq g N eq kg 1,4-DB eq kg 1,4-DB eq m3

Climate change Ozone depletion Freshwatereutrophication

Marineeutrophication

Freshwaterecotoxicity

Marine ecotoxicity Water depletion

Scenario a vs Scenario B

1. Polyphenol ScA 2. Polyphenol ScB


It can be observed that the main difference between scenarios are located under the climate change category,

due to the differing emissions: while cogeneration avoids electricity production from coal, gas, and petroleum,

gasification, using the same amount of WOP, can generate more energy: That means that avoids more electricity

and heat generation from non-renewable energy source. Moreover, gasification treatment has lower emissions.

4.4 LIFE CYCLE INTERPRETATION

4.4.1 Evaluation of significant issues

4.4.1.1 Completeness check

The aim of the completeness check is to determine if all important information about the study is available and

complete. This availability must satisfy goal and scope and allow to obtain results. In its representation, following

table 11 is shown.

Table 11. Completeness check

Phenolive prototype subsystem

Co

mp

lete

?

Action required

Sca Cogeneration

subsystem

Co

mp

lete

?

Action required

ScB Gasification subsystem

Co

mp

lete

?

Action required

Material production

x YES - NO x YES Recalculated

Energy supply

x YES x YES x YES Recalculated

Transport x YES x YES/

? Transport of WOP

- NO Collect data

Processing x YES x YES x YES Recalculated

Use x YES x YES x YES

End of life x YES - NO Out of the

system study

x YES Recalculated

For this analysis, a division of scenarios has been made, considering the different waste management methods

to be compared. As prototype is within both strategies, has been considered separate in completeness check.

In the PHENOLIVE prototype subsystem all life cycle stages have been considered. As determined in data quality

chapter, most of the inputs and outputs have been measured for this subsystem. Regarding first scenario,

material production of cogeneration facilities is not within the system due to is not exclusively built and working

for WOP treatment. For this reason, the end of life of this process has not either taken into account. In the

transport case, just WOP has been considered in the study, but not the transport of material.

For gasification scenario, the only life cycle stage not considered is transport due to lack of data. For the rest of

life cycle stages data have been calculated from a reference plant; for obtaining the inventory, reference plant

inventory has been multiplied by a ratio taken by power generated.

4.4.1.2 Sensitivity check

The aim of sensitivity check is to determine the reliability of the results and conclusions. With this purpose, some

modifications have to be introduced in the study and new results will be obtained, in order to contrast differences

between them.

In this case, according to the presented results, some modifications in the PHENOLIVE prototype would introduce

significant changes; ethanol ratio variation would let to know how an ethanol usage reduction would affect


environmental performance of the system. In this case, the obtained results have a determined ratio, and its

modification has not been tested.

Another way to design a sensitivity check is making modifications in the calculation methodology. For this study,

Midpoint ReCiPe method has been used. This method relies on three calculation perspectives H, I, E 46:

Perspective I (Individualist): based on short term, technological optimistic considering human adaptation

Perspective H (Hierarchist): Is the most commonly used perspective, considered as standard. There is no time-

frame in this one.

Perspective E (Egalitarian): Is the most precautionary model and considers the longest time-frame.

For the study, H model has been implemented due to be the most used perspective. Hence, the aim of this

sensitivity analysis is to compare H model with I and E. In order to carry out the analysis, the system has been

recalculated with both new perspectives and results are shown in following tables 12 and 13.

Two comparison have been created. In the first one, H and E methodologies have been reviewed, dividing the

calculation between both scenarios. In this case there are differences just for climate change and marine

ecotoxicity. According to the results, for the long term, the first scenario has slightly better results, but still worse

than gasification scenario increases 2% its value. Regarding marine ecotoxicity, there is a big difference between

two methods. After reviewing calculations, there is no mistake found.

Considering the results in table 12, is supposed scenario A has lower impacts at long-term, but second one still

remains a harmless option for PHENOLIVE waste treatment. Leaving aside marine ecotoxicity deviation (50% in

scenario B, 144% in first one) for climate change differences are no significant.

Table 12. Sensitivity check (ReCiPe H - E)

A (H) B (H) A (E) B (E) A

DEVIATION % B

DEVIATION %

Climate change kg CO2 eq 2,800 -4,480 2,470 -4,380 -0,330 -12 0,100 -2,23

Ozone depletion kg CFC-11 eq 4,43E-08 -7,67E-07 6,43E-08 -7,64E-07 0 45 0 0

Freshwater eutrophication kg P eq 0,002 -0,001 0,017 -0,001 0 900 0 0

Marine eutrophication kg N eq 3,33E-04 -1,05E-03 3,33E-04 -1,05E-03 0 0 0 0

Freshwater ecotoxicity kg 1,4-DB eq 0,023 -0,166 0,023 -0,167 2,00E-04 0,881 -0,001 0,602

Marine ecotoxicity kg 1,4-DB eq 0,022 -0,146 31 -67 31 140809 -67 46064

Water depletion m3 0,031 -0,041 0,031 -0,041 0 0 0 0

For the comparison between H and I methods, again, climate change and marine ecotoxicity are the only impacts

which are modified. In the case of climate change, some differences can be found: Scenario A has higher impact,

a significant 34% increase. Otherwise, scenario B has a decrease of 5% of climate change impact.

For marine ecotoxicity some important variations can be observed; for the first scenario, there is a reduction by

almost 50%, while in the second one there is an increase of 50% rise the results. Nevertheless, the global results

show that B scenario is still better.

In conclusion, short term study benefits climate change of B scenario by 5%, which is not very conclusive, but for

cogeneration scenario, the impact grows up to 34%.


Table 13. Sensitivity check (ReCiPe H - I)

A (H) B (H) A(I) B (I) A

DEVIATION % B

DEVIATION %

Climate change kg CO2 eq 2.319 -4.871 3,66 -4,70 0,860 30,714 -0,220 4,911

Ozone depletion kg CFC-11 eq 1.22E-07 -7.17E-07 6,43E-08 -7,64E-07 0 45 0 0

Freshwater eutrophication kg P eq 0.002 -0.001 0,002 -0,001 0 0 0 0

Marine eutrophication kg N eq 2.86E-04 -1.09E-03 3,33E-04 -1,05E-03 0 0 0 0

Freshwater ecotoxicity kg 1,4-DB eq 0.019 -0.169 0,023 -0,166 0 0 0 0

Marine ecotoxicity kg 1,4-DB eq 0.019 -0.149 0,013 -0,070 -0,009 -

42,273 0,076 -52,123

Water depletion m3 0.032 -0.039 0,031 -0,041 0 0 0 0

At the end, long-term scaled scenario A has a better environmental performance in reference to the standard

approach, while at short-term has higher impact. Otherwise, scenario B is better at long-term in reference to the

initial method. In any case, there are no results modification, due to scenario B has lower impacts in absolute

value than scenario A.

4.4.1.3 Consistency check

The objective of consistency check is to determine if the assumptions, methods and data are consistent with the

goal and scope. In table 14 results of consistency are shown.

Table 14. Consistency check

Phenolive Subsystem

Sca Cogeneration subsystem

ScB Gasification subsystem

ScA vs ScB Action

Data source Primary Calculated Primary Consistent No action

Data accuracy Good Medium Good Consistent Need real data for

cogeneration

Data age 0 years 6 /2 years 0 years Inconsistent Need real data for

cogeneration

Technology coverage

Pilot plant Industrial scale Calculated Pilot

plant Inconsistent No action (study target)

Time-related coverage

Recent Recent Recent Consistent Need real data

Geographical coverage

Europe Europe Europe Consistent No action

As mentioned before, in the first scenario description, cogeneration performance has been calculated from

theoretical data. For including emissions and intakes of the co-generation process, a suitable SimaPro project

was taken from ECOINVENT database. That is why data accuracy were rated as “medium”, since the information

has not been obtained for the specific facilities where EOP is sent. Thus the information in this scenario has two

sources: Calculations for performance (taking into account LHV value of WOP, and bibliography performance

percentage).

Regarding data age, 2 year value points in Ecoinvent process, while 6 years value refers to the percentage of

energy extracted from WOP.

In the case of technology coverage, label “Inconsistent” has been used because each data has a different coverage.


5 CONCLUSIONS

Throughout the study, different options have been considered for polyphenol extraction from olive pulp after

olive oil extraction. A prototype was developed in order to make this extraction, consequently its whole life cycle

has been considered: production of materials, use phase, and waste phase. The information for material

production and use phase has been directly measured from the prototype design and production.

Once the polyphenol extraction is done, the resulted WOP has to be treated, hence it integrates in conventional

treatment of WOP.

The PHENOLIVE proposal substitutes cogeneration treatment for gasification process which also can produce

heat and electricity power, which can be exploited for other uses.

Having those two waste management energy producer methodologies, the aim of this study is to determine

which one has a better environmental performance comparing both.

For that, a comparative Life Cycle Assessment has been conducted, considering a scenario for each waste

treatment method available in the previous description.

After collecting data for inventory chapter, impact assessment part was developed for scenario A, and after for

scenario B. When both scenario results were obtained, it has been compared.

The functional unit for both scenarios (in order to be comparable) are the treatment of 1Kg of WOP at the

entrance of PHENOLIVE prototype, during the whole system, until the end of the waste treatment process.

After the results, the second scenario (including gasification) turned out to be the best choice, due to it has a

better performance and can generate more energy than cogeneration. Taking as reference the functional unit,

the polyphenol extraction performance is the same since the method is the same for both scenarios, but for

energy production, second scenario generates more than 10 times first one; that is caused by different factors:

Firstly, gasification process has a better efficiency, as though as first steps of the project. Secondly, in scenario A,

only a part of the EOP is sent to energy production system, hence less energy is generated at cogeneration site;

this fraction has to be sent because power facilities are not within the drying installations, and the produced heat

and electricity are not used at the studied system. In the case of gasification scenario, all of WOP used for

polyphenol extraction is treated in gasification plant, due to gasification creates heat enough to dry out coming

WOP, and is treated same facilities.

In conclusion, after the study, it is clear that gasification is the best studied scenario due to its higher efficiency

and the higher amount of waste treated. Regarding the prototype, there is no difference, due to the fact that the

same machine has been considered in both scenarios.


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