pharmaceutical wastewater treatment plant
TRANSCRIPT
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CCB 4233
INDUSTRIAL EFFLUENT ENGINEERING
PROJECT 1: PHARMACEUTICAL INDUSTRY
GROUP 8
THASARATHAN A/L JAYAKRISHNA 16615
VENNESA JOHNNY TING 16112
WAN MAIZATUL FATHIRAH BINTI WAN ABDUL HALIM 16396
YAU WING TIM 16002
YIM SEE CHENG 16220
Date of Submission: 3rdDecember 2015
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TABLE OF CONTENTS
LIST OF FIGURES .............................................................................................................. ii
LIST OF TABLES ................................................................................................................ ii
1.0 DESCRIPTION OF PHARMACEUTICAL INDUSTRY ........................................... 1
2.0 IDENTIFICATION AND CLASSIFICATION OF EFFLUENT IN
PHARMACEUTICAL INDUSTRY ...................................................................................... 3
3.0 REGULATION LIMIT .............................................................................................. 6
4.0 PROPOSED TREATMENT STRATEGY .................................................................. 8
4.1 Preliminary Treatment ............................................................................................ 9
4.1.1 Screening ......................................................................................................... 9
4.1.2 Grit Removal ................................................................................................... 9
4.2 Biological Treatment Process ................................................................................ 10
4.2.1 Activated Sludge Treatment Process .............................................................. 10
4.2.2 Membrane Bioreactor Process (MBR) ............................................................ 11
5.0 MAJOR TREATMENT UNIT ................................................................................. 12
5.1 Overview of Membrane Bioreactor (MBR) ........................................................... 12
5.2 Design of Membrane Bioreactor (MBR) ............................................................... 15
5.3 Calculations for Membrane Bioreactor (MBR) ...................................................... 16
5.3.1 Determination of required SADm or SADp .................................................... 16
5.3.2 Determination of membrane air scouring capacity requirement ...................... 17
5.3.3 Determination of aerobic solid retention time ................................................. 17
5.3.4 Designation of aeration system....................................................................... 18
5.3.5 Examples of Calculations ............................................................................... 19
5.4 Operating Variables for Membrane Bioreactor (MBR) .......................................... 22
6.0 SUSTAINABILITY OF DESIGN ............................................................................ 24
REFERENCES ................................................................................................................... 25
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LIST OF FIGURES
Figure 1: Effluent Limit for A and C operations .................................................................... 7
Figure 2: Effluent Limit for B and D operations .................................................................... 7
Figure 3: Overall process flow diagram for industrial effluent treatment plant ....................... 8
Figure 4: Activated Sludge Treatment Process .................................................................... 11
Figure 5: Basic principle of membrane filtration.................................................................. 13
Figure 6: (1) Side-stream MBR; (2) Submerged MBR ......................................................... 13
Figure 7: Block diagram of MBR design[10]
........................................................................ 16
Figure 8: Activated-sludge nitrification kinetic coefficients at 20 C ..................................... 21
LIST OF TABLES
Table 1: Top 25 Pharmaceutical Companies .......................................................................... 2
Table 2: Pharmaceutical industry manufacturing process, input and waste generated[8]
......... 4
Table 3: Characteristics of effluent from pharmaceutical industry
[8]
..................................... 5Table 4: Design data of flat sheet membrane and hollow fiber membrane [10]....................... 15
Table 5: Design parameters, operating and maintenance conditions for MBR technology in
pharmaceutical industry [10] ................................................................................................. 22
Table 6: Characteristics of influent and effluent with MBR[10]
............................................ 23
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1.0 DESCRIPTION OF PHARMACEUTICAL INDUSTRY
Pharmaceutical firms are engaged in the discovery, manufacturing, and marketing of
legal drugs, biologics (viruses, toxins, serums, and analogous products), vaccines, andmedical devices such as pacemakers and prosthetics. The products are made for both
humans and animals. Pharmaceutical products, both prescription and over the counter
(OTC), account for a large share of the aggregate health care spending and represent
major account items in international trade transactions of developed countries[1].
The pharmaceutical industry is characterized by a high level of concentration with
twenty-five multinational companies dominating the industry. Table 1 shows the
information about these major pharmaceutical companies that are sorted in the order
of their 2014 revenues from the sales of pharmaceutical products. The rankings of the
top 25 pharmaceutical companies have been compiled from GlobalData's
pharmaceutical revenue figures, which are based on sales of prescription medicines,
including generics drugs[2].
Company HQ Location Revenue (million USD)
Novartis Switzerland 47,101
Pfizer US 45,708Roche Switzerland 39,120
Sanofi-Aventis France 36,437
Merck & Co. US 36,042
Johnson & Johnson US 32,313
GlaxoSmithKline UK 29,580
AstraZeneca UK 26,095
Gilead Sciences US 24,474
Takeda Japan 20,446
AbbVie US 20,207Amgen US 19,327
Teva Israel 18,374
Eli Lilly US 17,266
Bristol-Myers Squibb US 15,879
Bayer Germany 15,486
Novo Nordisk Denmark 15,329
Astellas Japan 14,099
Boehringer Ingelheim Germany 13,830
Actavis US 13,062Otsuka Japan 11,308
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Daiichi Sankyo Japan 10,430
Biogen Idec US 9,398
Baxter US 8,831
Merck KGaA Germany 7,678
Table 1: Top 25 Pharmaceutical Companies
Several characteristics distinguish the pharmaceutical industry from other industries.
A newly released pharmaceutical agent is usually available only by physician
prescription. Patients in effect transfer decision-making authority on the
appropriateness of medications for their ailments to the gate-keeping physicians (or
pharmacists and nurses in some countries). Generally, a prescription may become
available OTC (i.e., without physician prescription) for a non-chronic condition that is
relatively easy to self-diagnose and has low potential for harm from self-medication
under conditions of widespread availability[1]
.
Another important industry characteristic is the availability of health insurance
coverage for prescribed medications. Most often, private insurers or government
entities subsidize retail drug purchases. Consumers make a co-payment (a fixed sum
for each prescription regardless of the full price) or pay a coinsurance (a fixed
percentage of the full price) that is less than the full market price. Co-payments tend
to vary depending on the drug classification. Consumer payment of far less than full
cost of prescriptions creates the familiar moral hazard(excessive use) problem[1].
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2.0 IDENTIFICATION AND CLASSIFICATION OF EFFLUENT IN
PHARMACEUTICAL INDUSTRY
Industrial effluent is defined as any wastewater that is produced from any processes
that operate in the industry. Industrial effluent can be produced when process water is
in contact with raw materials, products, intermediates, by-products and waste
products at various operation units[3]
. In pharmaceutical industry, high quality water is
an important raw material for production, cooling and material processing operation
in manufacturing of drugs. In multiproduct pharmaceutical industry, various processes
and sub-processes are required for a wide range of drugs production. Therefore, the
amount of effluent generated is usually in an abundant amount with inadequate
characterization of components existing in product waste. Effluent generated from
pharmaceutical industry which contains contaminants, nutrients, toxin and organics is
a challenge from treatment process.
Effluent from pharmaceutical industry has high concentration of pollutants due to the
presence of non-biodegradable organic matter such as antibiotics, drugs, animal and
plants steroids, hormones, analgesics, heavy metal, spent solvents, reaction residues
and others. Moreover, the effluents normally possess high pH, Chemical Oxygen
Demand (COD) and Total Suspended Solids (TSS). Therefore, effluent treatment
plants (ETPs) is crucial for pharmaceutical industry as it maintain the level of COD
and other parameters by removing any toxic, organics, debris, dirt, grit, pollution and
toxic from effluent[4]. The controlled of effluent parameters is important to meet the
requirement set by regulatory board and minimize pollution problem to the
environments. Different separation techniques are used in ETPs such as evaporation,
drying, centrifugation and filtration for effluent treatment process. After separation
procedure, effluent can be discharged into the environment; however, the
characteristics and composition of effluent varies according to different company.
Effluents discharged are normally classified based on the type of components present
such as antibiotics, prescription and non-prescription drugs present. The growing
demand of various pharmaceutical products such as antibiotics, vaccine and medicine
has led to the released of contaminants into wastewater and then to environment in an
increasing pattern. The volume of contaminants are normally varies from nanogram to
low microgram per liter[5]. The contaminants can bring potential risk to human in
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terms of health impact and ecosystem without any prior notice. Effluent which
contains fluoroquinone antibiotics causes the mutation of bacteria when it is
discharged into river[6]
. Mutated bacteria become resistant to the antibiotics and
finally cannot be cured. Besides that, aquatic organism is more prone to the risk of
exposure with pharmaceutical contaminated water compare to human being.
The current method in ETPs possesses certain challenges and problems which should
be overcome in the future. The high temperature of effluent can cause instantaneously
damaged to aquatic organisms as they may experience thermal shock. Furthermore, a
sudden increase in temperature encourages the growth of water plants and fungus
which affect the balance of ecosystem. Furthermore, certain processes have utilized
an abundant amount of chemical for neutralization process which may increase
treatment cost. Bad odour presents in effluent stream which due to the decomposition
and decay of organic matter[7]. Therefore, advanced technology should be developed
to improve the efficiency of ETPs. The effluent from pharmaceutical industry can also
be known as the influent for wastewater treatment plant. Table 2 shows the process in
pharmaceutical industry manufacturing process and its typical waste generated[8]
.
Manufacturing
ProcessInput substances Waste generated
Chemical reaction Reactants, solvents, catalysts such as benzene,
toluene, methanol, xylene, hydrochloric acid,
chloroform, ethylene glycol
Residues and reactor
bottom wastes
Separation Separation and extraction solvents such as
acetone, hexanes, methanol and toluene
Residues
Purification Solvent for purification process such as methanol,
acetone, toluene and hexanes
Residues
Drying Active drugs and intermediates -
Natural productsextraction
Animal tissues, plant and extraction solvents Spent raw materials
Fermentation Starch, nutrients, phosphates, solvents such as
ethanol, methanol, acetone and amyl alcohol
waste filter cake and
residues
Formulations Sugar syrups for medicine formulations, binders
and drugs
Waste from packaging
and rejected drugs.
Table 2: Pharmaceutical industry manufacturing process, input and waste generated[8]
Researchers have been carried out experiments to determine the characteristics of
effluent from different pharmaceutical plants. Table 3 shows the typicalcharacteristics of the effluents.
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Parameters Characteristics
pH 3.9-4.0
TSS (mg/L) 5460-7370
TDS (mg/L) 2564-3660Total solids 8024-11030
BOD (mg/L) 11200-15660
COD (mg/L) 21960-26000
Colour Dark yellow
Chromium (mg/L) 0.057-1.11
Lead (mg/L) 0.559-6.53
Cadmium (mg/L) 0.036-0.484Nickel (mg/L) 0.892-2.35
Zinc (mg/L) 0.583-0.608
Arsenic (mg/L) 0.0049-0.0076
Phosphate (mg/L) 260-280
Table 3: Characteristics of effluent from pharmaceutical industry[8]
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3.0 REGULATION LIMIT
Organic solvents are widely used in the pharmaceutical production processes. In fact,
this industry is one of the largest users of organic solvent. The usage of organic
solvent comes with a drawback because they can be harmful to the environment and
human health if released unregulated. Therefore, treatment of wastewater from the
industry has to be carried out according to the regulatory limit set by the
environmental agency or the government before the effluent is considered safe to be
released to the environment. The regulatory limit is established to require a minimum
level of treatment for industrial point sources. This limit is usually based upon
demonstrated performance of model process and treatment technologies that are found
to be economically achievable.
Many countries have their own regulatory limit for the industrial activity that takes
place in the country. For this project, the regulatory limit from the United States will
be used as a reference because based on our point of view; the regulatory limit of the
United States covers a wider range as compared to other regulatory limit from other
countries. According to the regulatory limit of the United States for the
pharmaceutical industry, the limit is divided according to different subcategories
which are:-
1. Category A: Fermentation Operations
2. Category B: Biological and Natural Extraction Operations
3. Category C: Chemical Synthesis Operations
4. Category D: Mixing, Compounding and Formulation Operations
5. Category E: Pharmaceutical Research Operations
Besides, the regulatory limit of the United States establishes limitation based on
model process technologies and wastewater treatment technologies hence making it
more reliable and accurate. Therefore, facility owners and operators may use any
combination of process technologies and in-process or end-of-pipe wastewater
treatment technologies to comply with the required limits. The categories of
technologies are:-
1.
BPT: Best practicable control technology
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2. BCT: Best conventional pollutant control technology
3.
BAT: Best available technology economically achievable
4. NSPS: New source performance standards
5. PSES: Pre-treatment standards for existing sources
6.
PSNS: Pre-treatment standards for new sources
For this study, we will be focusing on the limit based on the best available technology
economically achievable. The regulatory limits are as follows:
Figure 1: Effluent Limit for A and C operations
Figure 2: Effluent Limit for B and D operations
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4.0 PROPOSED TREATMENT STRATEGY
A wide variety of products are made in the pharmaceutical industries, typically
requiring large volumes of chemicals, materials, and substances that are used
throughout process operations. Waste streams generated in these industries can be
heavily overloaded with contaminants, toxins, nutrients, and organic content,
presenting unique challenges in terms of treatment, especially as regulations become
more stringent.
Additionally, as is the case in other industrial manufacturing sectors, water is a critical
ingredient in pharmaceutical operations. Consistent and high-quality supplies are
needed for a range of purposes including production, material processing, and
cooling. As disruptions in raw water supply represent a significant concern, more
companies are turning to water efficiency initiatives to help mitigate water scarcity-
related risks. Basically, the treatment processes can be divided into the following
categories:
1.
Preliminary Treatment
2. Primary Treatment
3. Biological Treatment
4.
End Product
Figure below shows the overall process flow diagram for industrial effluent treatment
plant.
Figure 3: Overall process flow diagram for industrial effluent treatment
plant
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4.1 Preliminary Treatment
Preliminary treatment is designed to remove gross, suspended and floating
solids from raw sewage. It includes screening to trap solid objects and
sedimentation by gravity to remove suspended solids. This level is sometimes
referred to as mechanical treatment, although chemicals are often used to
accelerate the sedimentation process. Preliminary treatment can reduce the
BOD of the incoming wastewater by 20-30% and the total suspended solids by
50-60%. Preliminary treatment is usually the first stage of wastewater
treatment. Many advanced wastewater treatment plants in industrialized
countries have started with preliminary treatment, and have then added other
treatment stages as wastewater load has grown and the need for treatment has
increased[9].
4.1.1 Screening
Wastewater contains large solids and grit that can interfere with
treatment processes or cause undue mechanical wear and increased
maintenance on wastewater treatment equipment. To minimize
potential problems, these materials require separate handling.
Screening is the first unit operation used at wastewater treatment plants
(WWTPs). Screening removes objects such as rags, paper, plastics, and
metals to prevent damage and clogging of downstream equipment,
piping, and appurtenances[9].
4.1.2 Grit Removal
Grit includes sand, gravel, cinder, or other heavy solid materials thathave higher specific gravity than the organic biodegradable solids in
the wastewater. Removal of grit prevents unnecessary abrasion and
wear of mechanical equipment, grit deposition in pipelines and
channels, and accumulation of grit in anaerobic digesters and aeration
basins. Grit removal facilities typically precede primary clarification,
and follow screening. This prevents large solids from interfering with
grit handling equipment. In secondary treatment plants without
primary clarification, grit removal should precede aeration[9].
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4.2 Biological Treatment Process
Biological treatment is an important and integral part of any wastewater
treatment plant that treats wastewater from either municipality or industry
having soluble organic impurities or a mix of the two types of wastewater
sources[9]. The obvious economic advantage, both in terms of capital
investment and operating costs, of biological treatment over other treatment
processes like chemical oxidation and thermal oxidation cemented its place in
any integrate wastewater treatment plant over a century.
There are two main processes in the biological treatment process that will be
focused on in this project. They are:
1. Activated Sludge Treatment Process
2. Membrane Bioreactor Process
4.2.1 Activated Sludge Treatment Process
The old treatment plant consisted of an equalization basin,
neutralization, primary sedimentation, roughing biofilter, activated
sludge system, and rock trickling filter with final clarifiers. In the
proposed study, the old activated sludge system, rock filter, and final
clarifier were replaced with a new single-stage, nitrification-activated
sludge system. A schematic diagram of the pilot plant is presented in
the figure below.
The advantages of this process includes it is a chemical-free operation,
it produces extremely pure water, and full efficiency of wastewater
treatment can be obtained instantly.
However, there are some drawbacks resulting from this process. By
applying this process, large amount of sludge will be produced.
Besides that, microbiological contamination of the effluent may be
significant since there is no physical barrier between activated sludge
and treated water.
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Figure 4: Activated Sludge Treatment Process
4.2.2 Membrane Bioreactor Process (MBR)
Membrane bioreactor (MBR) technology combines biological-
activated sludge process and membrane filtration. MBR technology is
also used in cases where demand on the quality of effluent exceeds the
capability of CAS. With the development of submerged membranes,
firstly introduced by Yamamoto et al., the number of MBRs treating
municipal wastewater increased while the MBR market is currently
experiencing accelerated growth.
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5.0 MAJOR TREATMENT UNIT
From the justifications of the available treatment methods for the treatment of
wastewater from the pharmaceutical industry, the one major process unit that will be
focused on in this project is the membrane bioreactor (MBR). Further descriptions,
design, calculations and operating variables related to MBR are shown below.
5.1 Overview of Membrane Bioreactor (MBR)
Membrane bioreactor (MBR) technology incorporates biological-activated
sludge process and membrane filtration [10],[11]. It is the most important recent
technological advance developed and applied to fulfill the shortcomings of the
conventional activated sludge (CAS) process in treating wastewater with
varying composition and fluctuating flow rate. MBR has attracted growing
interests with its distinct advantages of smaller footprint, less sludge
production, higher separation efficiency and highly improved effluent quality
as compared to CAS[12]. Due to these reasons, MBR is widely used for
municipal and industrial wastewater treatment especially in the pharmaceutical
industry as it performs excellently in removing pharmaceutically active
compounds, organic matter and suspended solids, nitrification/ denitrification
and phosphorus and more[10].
MBR is a suspended growth-activated sludge system that utilizes microporous
membranes for solid/ liquid separation instead of secondary clarifiers[10]. It is a
physical process where separated compounds remain chemically unchanged.
The fundamental principle lies behind is shown in Figure 5 where feed water
passes through the membrane surface to produce permeate and the rejected
constituents form concentrate or retentate. A membrane is simply a two-
dimensional material used to separate components of fluids based on their
relative size or electrical charge. The transport of only specific compounds
through the membrane is called semi-permeable filtration[10]
.
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Figure 5: Basic principle of membrane filtration
The mass balance of this physical process can be represented by the equation
below
Where = feed flow rate, = solute concentration in feed flow, =
permeate flow rate, = solute concentration in permeate, = concentrate
flow rate and =solute concentration in concentrate.
There are two types of MBR configurations namely: (1) side-stream MBR
with external pressure-driven membrane filtration (2) submerged MBR with
internal vacuum-driven membrane filtration (see Figure 6). Submerged MBR
is more commonly used as compared to side-stream MBR due to its low
energy consumption and fouling on module is less pronounced. Shear
enhancement is important in both configurations as it helps to prevent
membrane fouling with the constituents of mixed liquor by lowering the
permeate flux. Side-stream MBR provides shear through pumping whereas
submerged MBR employs aeration in the bioreactor to provide it[11].
Figure 6: (1) Side-stream MBR; (2) Submerged MBR
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Aforementioned, the performance of MBR may be limited by fouling during
filtration of activated sludge. Fouling occurs in such a way that it reduces long
term flux stability on the membrane surface and within the pores necessitating
membrane cleaning. When cleaning fails to produce adequate flux recovery,
the membrane will have to be replaced. This leads to addition of repair and
maintenance cost to the overall cost. As a result to that, several techniques are
employed to reduce fouling which are reduction of flux, promotion of
turbulence to limit the thickness of the boundary layer, and periodical
application of cleaning measures to remove the cake layer and foulants[11].
MBR is highly recommended to be used in the pharmaceutical industry due to
its capability in removing pharmaceutically active compounds (PhACs) and
other organic compounds effectively. Most pharmaceutical substances are
biologically act ive and persistent to avoid degradation before transmitting its
curing effect. For this reason, pharmaceutical residuals are usually not
completely degraded or retained by adsorption to sludge but end up in
receiving waters. MBR is able to enhance trace-organic removal to a greater
extent as it has higher sludge age, higher biomass concentration, complete
retention of solids and microorganisms, etc. Several studies have been carriedout to verify the performance of MBR in the elimination of PhACs such as
lipid regulators and cholesterol lowering statin drugs, -blockers, antibiotics,
anti-ulcer agent, analgesics and anti-inflammatory drugs[10]. Studies show that
the COD removal efficiencies of MBR can achieve a percentage of 93.7 to
97.8%[13]
. Besides, problem of large amount of sludge recycling and sludge
disposal in the conventional activated sludge process can also be reduced to a
great extent, that is, 0.027g VSS (volatile suspended solids)/g COD removed.
In addition, shock in organic loading does not result in a failure of the
capability of MBR to treat the water.
Hence, complete solids removal, significant disinfection capability, high rate
and high efficiency organic removal and small footprint have made MBR an
excellent treatment solution to cope with the growing needs for transforming
wastewater into clean water in the pharmaceutical industry.
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5.2 Design of Membrane Bioreactor (MBR)
Four key parameters are important for the operation and maintenance of MBR
such as flux, permeability, aeration, clean frequency and protocol[11]
. Among
the parameters mentioned, design flux is a very important parameter in
designing a membrane bioreactor (MBR). The stability of the process is
greatly influenced by design flux as stability increases with lower design
flux[11]. Moreover, the determination of area for MBR design should be
constrained by budget available and risk level.
Flux can be defined as volume per area per unit time in which to express the
rate at which wastewater permeates a membrane in MBR. SADp is a key
indicator in MBR technology with respect to air supply. It is defined as the
ratio of membrane aeration demand to flux. In designing MBR, low-fouling
membrane and efficient membrane air scour reduces SADp and further reduces
energy demand which enable it to emerge as an important wastewater
treatment method in industry compare to others such as Activated Sludge
Process (ASP). Furthermore SADm indicates the flowrate of air scour per
membrane area. This parameter is necessary to aerate the membrane unit in
MBR in order to remove solids particles[11]. A comparison study is tabulated
in Table 4 regarding the design of flux, permeability, SAD mand SADpin two
different configurations of MBR technology which are flat sheet membrane
and hollow fibre membrane.
ConfigurationsFlux,
LMH
Permeability,
LMH/bar
SADm
[Nm3/(m
2.h)
SADp
Flat Sheet
MembraneMean 19.4 261 0.57 27.5
Hollow Fibre
MembraneMean 19.5 104 0.30 15.4
Table 4: Design data of flat sheet membrane and hollow fiber membrane[10]
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Besides that, the design of MBR can be summarized as shown in the block
diagram in Figure 7 with material balance shown. This designed is referred to
the calculations done based on Kubota 515 Panel RM/RW Module[11]
.
Vanoxic tank = Volume of anoxic tank
V aeration tank = Volume of aeration tank
V membrane tank,min = Minimum volume of membrane tank
Figure 7: Block diagram of MBR design
[10]
5.3 Calculations for Membrane Bioreactor (MBR)
5.3.1 Determination of required SADm or SADp
Specific air demand based on membrane area (SADm) is defined as scouring
air flow rate per membrane area. SADm does not reflect the cost performance
of a specific membrane as it is not sensitive to flux and the air pressure
required. It is the ratio of QA to membrane area.
Where, QA is membrane aeration rate (m3/hr) and Am is total membrane
surface area (m2).
The specific air demand based on permeate volume (SADp)is defined as
scouring air volume per permeate volume. SADPis often used to compare the
air utilization efficiencies of membranes.
V aeration tank =
10156.48m
3
Vanoxic tank=
7555.6m
3
V membrane tank,min =
1825m3 (Kubota)Q influent =2518.5 m3/h
Q sludge wastage rate
= 1144.7m3/h
Effluent
Recycle ratio=1.54
Recycle ratio=4
http://onlinembr.info/Cost/SAD%20in%20literature.htmhttp://onlinembr.info/Cost/SAD%20in%20literature.htmhttp://onlinembr.info/Cost/SAD%20in%20literature.htmhttp://onlinembr.info/Cost/SAD%20in%20literature.htmhttp://onlinembr.info/Cost/SAD%20in%20literature.htmhttp://onlinembr.info/Cost/SAD%20in%20literature.htmhttp://onlinembr.info/Cost/SAD%20in%20literature.htmhttp://onlinembr.info/Cost/SAD%20in%20literature.htmhttp://onlinembr.info/Cost/SAD%20in%20literature.htmhttp://onlinembr.info/Cost/SAD%20in%20literature.htmhttp://onlinembr.info/Cost/SAD%20in%20literature.htm -
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Where, QAiris air flow rate (m3/hr), J is flux (m/hr) and Amis total membrane
surface area (m2).
5.3.2 Determination of membrane air scouring capacity requirement
Designing air scouring system is one of the key technical challenges in MBR.
Air flow rate must be uniform among nozzles so that the membranes above the
nozzles are evenly scoured. Otherwise, a localized membrane fouling occurs
where the scouring air is not sufficient. The air scour energy in a MBR system
causes a high turbulent and surface contact to remove solid particles that
attach to the surface of the membrane as well as to protect from membrane
fouling which might cause lower production, lower membrane life and greater
operational cost. In order to determine the total net amount of air required to
perform biological treatment, calculation for the Mo(Oxygen requirement for
biological treatment) and Mm (Oxygen transferred by membrane aeration)
should be done.
In addition, aeration plays a vital role in the designation of membrane surface.
The membrane modules must be designed efficiently to maximize the mass
transfer in the internal spaces of membrane module thus allowing a systematic
use of scouring air. The submerged membrane typically needs a coarse bubble
aeration (air scouring) to remove flocculants and if the designation is not done
properly it might run inefficiently, causing a hike in energy bills and affects
the overall turndown capabilities.
In addition, in the case of hollow fiber membrane, rising bubbles also increase
random fiber movement that causes acceleration and deceleration of fibers in
liquid, which greatly increases the anti-fouling effect.
5.3.3 Determination of aerobic solid retention time
Assumptions:
Temperature below 280C.
Excess DO to supply the active microorganisms enough oxygen for
biochemical reaction
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Where,
n = specific growth rate of nitrifying bacteria, g new cells/ g cells.d
nm = maximum specific growth rate of nitrifying bacteria, g new cells/ g
cells.d
N = Nitrogen concentration, g/m3
Kn = Half velocity constant, substrate concentration at one-half the
maximum specific substrate utilization rate, g/m3
kdn = Endogenous decay coefficient for nitrifying organisms, g VSS/ g
VSS.d
But for fully complete-mix activated sludge nitrification system, at
temperature below 25C with sufficient DO present, nitrification rates are
affected by the liquid DO concentration in activated sludge. To account for the
effects of DO, the expression for the specific growth rate described above is
modified as follows:
Where DO = dissolved oxygen concentration, g/m3
K0= half-saturation coefficient for DO, g/m3
5.3.4 Designation of aeration system
Same like all aerobic biological systems, the biomass contained in the MBR
needs to have a continuous amount of oxygen supply to carry out its chemical
reactions. The appropriate amount oxygen must be supplied to all the
microorganisms and wastewater to carry out these demands:
Carbonaceous biochemical oxygen demand (BOD): conversion of the
carbonaceous organic matter in wastewater to cell tissue and various
gaseous end products
n = (nmN / Kn +N ) - kdn
n = (nmN / Kn +N ) ( DO / KO +DO ) - kdn
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Nitrogenous BOD: ammonical nitrogen is oxidized to the intermediate
product nitrite, which is then converted to nitrate; this process is
nitrification
Inorganic chemical oxygen demand (COD): oxidation of reducedinorganic compounds within the wastewater.
5.3.5 Examples of Calculations
Assumptions:
1.
Flux for the system, J is 10 L/m2.h
2. Average flow of wastewater is 70 Nm3/h and 30 m
3/h
3. Area of membrane = 240 m2
4. Packing density of membranes is 115 m2/m
3
5. The initial soluble BOD, So = 150 g/m3and the final soluble BOD, S =
15 g/m3
6. DO concentration in the influent = 1.5 g/m3
7. Mass of mixed liquid suspended solid, MLSS = 250 kg/d with density
of 8 kg/m3
8. Nitrogen concentration, N = 1.0 g/m3
9.
Space time, is 3 hours
The energy demand for the aeration system can be determined via the specific
aeration demand (SAD) with reference to the volume of wastewater intake.
SADp =
(m3 of Air / m3of permeate)
=
= 29.2 m3of Air / m
3of permeate
To calculate the total membrane area required,
Am =
=
= 3000 m2
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Since the area of one membrane unit = 240 m2
Nmembrane=
= 10.4
= 11 membranes
To calculate the minimum volume of the membrane tank,
Vmin =
=
= 26.1 m3
To calculate the growth rate at 12C,
nm = (
) x (1.07)12-20
= 0.44 g/g.d
Kn = 0.74 g/m3x (1.053)12-20
= 0.49 g/m3
Kdn = 0.08 g/g.d x (1.04)12-20
= 0.06 g/g.d
Substituting these values into the equation above, the n is calculated to be
0.672g/g.d
Given that the solid retention time,
SRT =
=
= 1.49 days
Multiplying with a scaling factor of 1.25,
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SRT = 1.49 days x 1.25
= 1.86 days
Given that the mass of MLSS = 250 kg/d @ 8 kg/m3, the volume required for
the aerobic tank =
Vaer = 250 kg/d x 1.86 d
= 465.03 kg 8 kg/m3
= 58.13 m3
Given that flow rate of influent = 30m3/h,
Vano = Q x
= 30m3/h x 3h
= 90 m3
Figure 8: Activated-sludge nitrification kinetic coefficients at 20 C
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5.4 Operating Variables for Membrane Bioreactor (MBR)
The detailed design parameters, operating and maintenance condition of MBR
in pharmaceutical industry for effluent treatment is tabulated in Table 5. It
shows the design data of a well-known MBR manufacturer in Italy which is
Kubota. This represents the typical parameters for the design of MBR
technology in pharmaceutical industry.
Design Parameters Data
Membrane aeration capacity (Nm3/h) 90-180
Biological aeration capacity (Nm3/h) 160
F/M ratio 0.04-0.18
HRT (h) 10.2-15.4
SRT (day) 27-70
MLSS (g/L) 10.5-12
Chemical cleaning reagents
(Clean frequency and protocol)
NaOCI, 0.5% followed by 1% Oxalic acid
(Backflow and soaking for 2 horus)
SADm(Nm /hm ) 0.75
SADp(Nm3air/m3permeate) 60-90
Mean permeability 200-250 without relaxation
LMH/bar 500-800 with relaxation
Permeability decline kt, LMH/(barh) 1.5
Table 5: Design parameters, operating and maintenance conditions for MBR technology
in pharmaceutical industry[10]
The constituent of influent and effluent after treatment process through MBRprocess is tabulated as below in Table 6 based on the block diagram of MBR
design. Based on Table 6, the difference between parameters of influent and
effluent constituent from MBR technology is obvious in terms of its BOD,
COD, TSS and TKN value. Total Kjedaldahl Nitrogen (TKN) is defined as the
sum of nitrogen, ammonia and ammonium content in wastewater. The
reduction of concentration in each constituent shows that MBR is effective in
treating the wastewater content from pharmaceutical industry based on the
design carried out by using Kubota Module.
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Constituent Unit Influent Effluent Typical effluent
quality from MBR
BOD5 g/m 153.3 0 5
COD g/m 284.9 45 -Total suspended solids
(TSS)
g/m 92.5 3.94 5
Total Kjedaldahl nitrogen
(TKN)
g/m 33.8 3.9 -
Table 6: Characteristics of influent and effluent with MBR[10]
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6.0 SUSTAINABILITY OF DESIGN
Due to global environmental concerns, it is highly beneficial if wastewater effluent is
selectively reuse for agriculture and industrial purposes or utilized as low cost
substrates for energy production and value added products[12].
1. MBR utilization for biofuel production
Biogas is renewable fuel produced from the activity of methanogen. MBR
stands a potential in biofuel production with its anaerobic biological
process for wastewater treatment.
2. Electricity production
There is a restriction in the application of MBR which is the high energy
consumption, estimated at 0.8-1.1 kWh/. The use of microbial fuel cells
(MFC) with MBR is able to convert chemical energy in organic matters
into electrical energy by catalytic reaction of microorganisms. In other
words, MFC can provide clean and safe energy, quiet performance, low
emissions and ease the operation of treatment.
3. Nutrients and metals recovery
Phosphorus recovered via MBR can be used for food production, primarily
for the production of fertilizer and animal feed additions. Besides, studies
also show that MBR is able to recover nitrogen from the effluent for a
fraction of about 90%.
All in all, the attractive advantages and interesting engineering characteristics of
membrane bioreactor (MBR) have great potential to play a vital role in wastewater
treatment for sustainable development and green tomorrow.
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REFERENCES
1. Gale, T., Pharmaceutical Industry, in International Encyclopedia of the Social
Sciences. 2008.
2. PMLiVE. Top 25 Pharma Companies by Global Sales. 2015 [cited 2015 November
14]; Available from:http://www.pmlive.com/top_pharma_list/global_revenues#.
3. C, G., et al., Pharmaceutical industry wastewater: Review of the technologies for
water treatement and reuse.Industrial & Engineering Chemistry Research, 2014. 53:
p. 11571-11592.
4. Deschamps, E., et al., Managemennt of effluents and waste from pharmaceutical
industry in Minas Gerais, Brazil.Brazilian Journal of Pharmaceutical Sciences, 2012.
48(4): p. 727-736.
5. Kavitha, R.V., V.K. Makam, and K.a. Asith, Physio-Chemical analysis of effluents
from pharmaceutical industry and its efficiency study. International Journal of
Engineering Research and Applications (IJERA), 2012. 2(2): p. 103-110.
6. Adebayo, G.B., et al., Assessment and biological treatment of effluent from a
pharmaceutical industry.Scholars Research Library, 2014. 1(4): p. 28-33.
7. HyCa Technologies PVT LTD. 2015, HyCa Technologies PVT LTD.
8. Rana, R.S., et al.,A review on characterization and bioremediation of pharmaceutical
industries' wastewater: an Indian perspective.Applied Water Science, 2014.
9. Zaerpour, M., Design, Cost & Benefit Analysis of a Membrane Bioreactor. 2013-
2014, Department of Environmental and Geomatic Engineering.
10. J, R., Membrane Bioreactor ( MBR ) as an Advanced Wastewater Treatment
Technology.2008. 5: p. 37-101.
11. Zaerpour, M., Design, cost & benefit analysis of a membrane bioreactor. 2014,
Department of Environmental and Geomatic Enginering, Politecnico di Milano:
Milano.
http://www.pmlive.com/top_pharma_list/global_revenueshttp://www.pmlive.com/top_pharma_list/global_revenues -
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12. H., N.C., et al., Green technology in wastewater treatment technologies: Integration
of membrane bioreactor with various wastewater treatment systems,. Chemical
Engineering Journal, 2015. 283: p. 582-594.
13. K, G.S. and H. Y, 5 Treatment of Pharmaceutical Wastes.Waste Treat. Process Ind,
2006: p. 167-233.