TREATMENT OF WASTE WASTER

FROM CASHEW NUT PROCESSING

INDUSTRY

VISHNU RAJ R

14CE63R09

INTRODUCTION

India is a leading producer ,processor & exporter of

cashew in the world with annual production of

6,20,000 MT.

Cashew nut industries are mostly located in

peninsular india .

Listed as "Orange" Category Industries by various

SPCBs.

There are two commonly followed methods of

cashew nut processing

Roasting process & Cooking process

PROCESS FLOW

DIAGRAM

INDIAN SCENARIO

Roasting process is more popular in India, mostly in Kerala.

The roasting of cashew seeds is carried out in an inclined rotating open drum. Due to the high temperature of the drum, the CNSL in the cashew nut catches fire spontaneously and the nuts are roasted

The cashew nuts, in burning state, are discharged at the outlet of the drum and quenched immediately with spray of water to prevent further roasting.

These are small and medium scale industries ,man power intensive and with majority having no pollution abatement systems.

SOURCES OF WASTE WATER GENERATION

Initial washing of the raw cashew nuts.

Water used in the humidification step

Washing of flue gases from boiler

Washing of the equipment and the floor

CHARACTERSTICS OF EFFLUENT

The main liquid waste from the cashew nut processing are contaminated with CNSL (Cashew Nut Shell Liquid)

CNSL is a caustic, viscous liquid, which contains phenolics, mainly cardanol (60–65%).

CNSL is a liquid immiscible in water, because their components are highly hydrophobic

These phenolic compounds of high persistence, have acid characteristics, potentially carcinogenic and mutagenic

Despite being a by-product collected for marketing,

significant amount of CNSL is lost in the effluent. This is

due to the fact that extraction process is not yet fully

efficient.

The effluent generated has its color & varies from dark

brown and black.

Treatment is often difficult by conventional means, as

these compounds inhibit normal microbial populations of

functions, therefore, affecting the biological treatment

process (Rajkumar & Palanivelu, 2004).

COMPOSITION OF CNSL

CNSL is used for the production of paints, varnishes

,dyes, lubricants, disinfectants, insecticides.

EFFECTS ON WATER BODIES

Concentration above 1 mg/L can affect aquatic life.

The acute hazard to fish, aquatic invertebrates, and

aquatic plants is based on estimated toxicity values

for cardanol of 0.001 mg/L, 0.004 mg/L, and 0.010

mg/L, respectively.

Alkylphenols like cardanol have low solubility and

can contaminate the sediments of rivers (Unger &

Newman ,2003)

Source: U.S. EPA December, 2009 Hazard Characterization Document

WASTEWATER DISCHARGE

CHARACTERIZATION

Parameter mg/l

TSS - 1175 –2115

TDS - 2240 –4284

O&G - 1400 –2068

BOD - 5200 –10,424

COD - 14,790 –27,600

pH - 7.2-8.2

Source:CPCB

ECOTOXICOLOGICAL ANALYSIS OF CASHEW

NUT INDUSTRY EFFLUENTS

This study assessed the toxicity of this industrial effluent, specifically two of its major components, cardoland cardanol, using the brine shrimp (Artemia sp.) lethality assay

Survivors were counted after 24 and 48 hr of incubation of nauplii with samples.

The LC50 of cardol was 0.56 and 0.41 mg/L after 24 and 48 hr exposures, respectively, and of cardanol was 1.59 and 0.42 mg/L

Data from this study suggested that the cashew nut industry effluents are highly toxic to the environment in the Artemia sp. model and are potentially harmful to the environment

Martins et al , Pan-American Journal of Aquatic Sciences (2009),

WASTE WATER DISCHARGE STANDARDS

Parameter mg/l

BOD (270C and 3 days) - 30

Oil & Grease - 10

Suspended Solids - 100

Phenol - 1.0

pH - 6.5-8.5

Source :CPCB

EFFLUENT TREATMENT

Wastewater will be collected in a terminal collection

cum buffer tank.

Being a reclamation project, the entire wastewater

has to be collected in a central place and treated to

meet the good quality BOD norm of < 20 mg/l.

SBR (Sequential Batch Reactor) system is normally

recommended which will consist of:

Collection-cum-aeration-cum-settling tank

Sand Bed Filter system for decanted water filtration

Sludge drying bed for excess sludge

CPCB industrial document

AEROBIC REACTOR WITH FUNGAL

INOCULUMS (MARCUS ET AL)

Studies were conducted to assess the feasibility of an aerobic reactor inoculated with the fungus Aspergillus niger in reducing the toxicity of the effluent from the cashew processing industry

The study was on the effluent from WWTP of an industry that offers a treatment which basically consists of five steps: separation of coarse solids; equalization with aeration; screening; decantation and addition of hydrogen peroxide (aqueous 15 to 20% concentration) .

Reactor in this study used an aerobic fixed bed reactor and upward continuous flow inoculated with the fungus Aspergillusniger found in the waterbodies receiving effluent from indutry.

Once the nutrient solution started to be fed to the reactor the process of developing fungi were accelerated.

The analysis results show a significant positive correlation between both toxicity and phenolic content (correlation coefficient = 0.53), and between toxicity and COD (correlation coefficient = 0.60)

Fungal fixed bed reactor and upflow operated with a hydraulic retention time of 12 hours was highly efficient in reducing toxicity, total phenols and COD of effluent studied.

Filamentous fungi inoculated was dominant initially but at the end of the experiment yeast were capable of degrading the effluent satisfactorily.

The fact that yeast manage to survive in such a hostile effluent environment, degrading it and dominating all the space at the expense of filamentous fungi, highlights the great adaptive capacity of these organisms.

ENZYMATIC BIOREMEDIATION OF CNSL

CONTAMINATION(SOLY ET AL)

The aim was to find the utility of enzymes,

oxidoreductases and proteases for the

bioremediation of CNSL

The results show that peroxidase reduced the color

of the CNSL solution by polymerization and

precipitation.

Laccase, papain and fungal and bacterial protease

degraded the phenolic constituents.

The degradation was mainly at the double bonds of

the C15 hydrocarbon chain of the cardanol

BIOAUGMENTATION OF WASTEWATER FROM CASHEW

INDUSTRY (JERONIMO ET AL. 2012)

The study was aimed to assess the technical feasibility of the application of specific commercial strains of microorganisms (bioaugmentation) in the treatment of effluent coming from the processing of cashew nuts

The effluents collected were from the washing processes and humidification of cashew nuts.

Treatment tests were conducted with the addition of additive dose(about 25 mg / L).

The additive comprised of enzymes and viable bacteria (e.g. Pseudomonas aeruginosa LP602, Acinetobacter calcoaceticus)

Effectiveness of COD removal was measured on different operating conditions-anaerobic process ,aerobic process (without agitation) and the aerobic process with mechanical agitation.

The performance was monitored at the above three conditions ,observing change in pH, Acidity , COD, conductivity and turbidity over time.

It was concluded that the application of aerobic technique with agitation proved to be more viable with removal COD of the medium at levels greater than 80%.

TREATMENT ALTERNATIVES

The fungi used in biological reactors appear to be an alternative for the treatment of industrial effluents.

The potential of these microorganisms to degrade different types of substrates due to secretion of different enzymes, which act on the organic pollutant , making it more accessible to biodegradation (Rodrigues et al, 2006) .

In addition, the rapid reproduction and proliferation of these microorganisms and the ability to withstand possible variations of organic matter, oxygen, moisture and pH can be mentioned as indicators of viability employ them in biological reactors for the wastewater treatment (Rodrigues et al., 2006).

Such microorganisms in general, they promote degradation of aromatic compounds, through enzymatic systems P450 monooxygenase and lignolítico (Prenafeta boldu 2002).

CONCLUSION

Cashew nut industry waste water is rich in phenolic

contents.

Conventional biological treatments to these

effluents are not satisfactory as they contain high

amount of not easily biodegradable contents.

Bio remediation technologies can be used for

treatment of these type of waste water.

Reactors using Fungi is another alternative for

treatment.

REFERENCES Cashew nut processing: Sources of environmental pollution and standards-Atul mohod,

Sudhir jain and Powar A.G.

Bioaugmentation of wastewater from cashew industry- C. E. M. Jerônimo, H. G.

Fernandes , H. N. S. Meloe, J. F. Sousa

Removal of macronutrients from effluent of a cashew nut industry by using a batch

aerobic reactor with fungal inoculums- Marina Santos da Silva Lopes; Patrícia Celestino

Carvalho de Oliveira; Marcus Vinícius Freire Andrade

Comprehensive Industry Document – Cashew Seed Processing Industries,CPCB

Ecotoxicological analysis of wastewater of cashew chestnut processing industry before

and after treatment in aerobic reactor inoculated with fungi.- Marcionília Fernandes

Pimentel ,2010

Technical study for alternative treatment of oily wastewater arising from the cashew nut

industries- jerônimo, carlos enrique de medeiros

Organic matter removal efficiency of phenolic wastewater of cashew processing

industry by batch reactor with use of Aspergillus niger AN 400-Carla Bastos VIDAL

Degradation of Cashew Nut Shell Liquid by Pseudomonas sp Isolated from Soil- T.

Rajeswari, B. Padmapriya

Isolation, Identification and Methanogenesis of CNSL Degrading Bacteria and

Immobilized Bioremediation Techniques of CNSL and its Contaminated Water from

Cashew Industry- S. Sabna Prabha,

Enzymatic bioremediation of cashew nut shell liquid contamination-Soly Cheriyan,

Emilia T. Abraham