Electronic Industry Waste Water

1
CHAPTER 1
INTRODUCTION
1.1 GENERAL
Wastewater treatment is a process to convert wastewater which is water no longer needed or
suitable that can be either returned to the water cycle with minimal environmental issues or
reused. The principal objective of wastewater treatment processes is generally to allow
human and industrial effluents to be disposed of without danger to human health or to the
natural environment. Wastewater treatment is closely related to the standards and/or
expectations set for the effluent quality. Such treatment processes are designed to achieve
improvements in the quality of the wastewater after making use of different processes. By-
products from wastewater treatment plants, such as screenings, grit and sewage sludge may
also be treated in a wastewater treatment plant. If the wastewater is predominantly from
municipal sources (households and small industries) it is called sewage and its treatment is
called sewage treatment and if it is from the manufacturing plant or other facilities in the
form of effluent then it is called as effluent treatment. Wastewater treatment plants may be
distinguished by the type of wastewater to be treated, i.e. whether it is sewage, industrial
wastewater, agricultural wastewater or leachate.
Conventional wastewater treatment consists of a combination of physical, chemical, and
biological processes and operations to remove solids, organic matter and, sometimes,
nutrients from wastewater. General terms used to describe different degrees of treatment, in
order of increasing treatment level, are preliminary, primary, secondary, and tertiary and/or
advanced wastewater treatment.
Industrial effluent is any wastewater generated by an industrial activity. Such an
industrial activity is any process that involves the creation of any object or service for profit.
This process involves various steps of manufacturing which further make use of water. The
wastewater generated from such facilities comes in the form of effluent wastewater. Because
of the increase of the demand, industrial output is forced to increase day by day. This further
led to a substantial increase in the demand of water. However, for the sustainability of the

2
manufacturing processes wastewater produced is now widely being treated before
discharged in to the stream.
The electronics industry, especially meaning consumer electronics, emerged in the 20th
century and has now become a global industry worth billions of dollars. Contemporary
society uses all manner of electronic devices built in automated or semi-automated factories
operated by the industry. The size of the industry and the use of toxic materials, as well as
the difficulty of recycling has led to a series of problems with electronic waste. International
regulation and environmental legislation has been developed in an attempt to address the
issues.
1.2 Electronics Industry in India
Indian Electronics industry dates back to the early 1960's. Electronics was one industry
initially restricted to the development and maintenance of fundamental communication
systems including radiobroadcasting, telephonic and telegraphic communication, and
augmentation of defense capabilities. Until 1984, the electronics Industry was primarily
government owned and then in 1980s witnessed a rapid growth of the electronics industry
due to sweeping economic changes, resulting in the liberalization and globalization of the
economy. In the year 2005 India's electronic consumption was around 1.8 %. It is likely to
touch 5.5 % in 2010. According to a study conducted by ISA and Frost Sullivan, India's
semiconductor market would grow by 2.5 times. The end user products of semiconductor
would include mobile handsets, desktop and notebooks, PCs, etc.
(Source: Indian Mirror)
The electronics market of India is one of the largest in the world and is anticipated to reach
US$ 400 billion in 2022 from US$ 69.6 billion in 2012. The market is projected to grow at a
compound annual growth rate (CAGR) of 24.4 per cent during 2012-2020. Total production
of electronics hardware goods in India is estimated to reach US$ 104 billion by 2020. The
communication and broadcasting equipment segment constituted 31 per cent, which is the
highest share of total production of electronic goods in India in FY13, followed by consumer
electronics at 23 per cent. The growing customer base and the increased penetration in

3
consumer durables segment have provided enough scope for the growth of the Indian
electronics sector. Also, digitization of cable could lead to increased broadband penetration
in the country and open up new avenues for companies in the electronics industry.
(Source: India Brand Equity Foundation - IBEF)
1.3 Wastewater from Electronics Industry
Great quantities of harmful wastewater are produced during the production processes of
electronic products and components. If factories were to discharge wastewater into rivers or
arbitrarily into the streams, it would cause the serious harm to ecological resources in the
surroundings which can be very fatal. Wastewater treatment systems not only change
poisoned substances into non-poisoned substances, but also recycle water resources so they
can be used again. Because of the many chemicals used in the electronics industry for
numerous processes, wastewater generation is quite high in this industry. Waste may
include- organic and inorganic wastes, acids and alkalis, heavy metals, oil and grease,
biological wastes, etc. Organic waste is collected separately from wastewater systems.
Acids and alkalis are sent to onsite wastewater treatment facilities for neutralization after
segregation of heavy metal bearing streams. Treatment steps for electronics industry
wastewater may include precipitation, coagulation, sludge dewatering, sedimentation,
skimming, activated sludge process, filtering or membrane separation depending upon
wastewater streams, softening, demineralization, activated carbon process, cooling towers,
ultra filtration process and reverse osmosis, etc.
Heavy metals are also found in the wastewater from industrial discharges. Semiconductor
industries may contribute heavy metals like Selenium, Cadmium, etc. in the wastewater
streams. These are too harmful if not disposed properly and their treatment should be in the
line with standards. Electroplating industry also produces large amount of heavy metals in
various processes. There have been many incidents reported where wastewater from the
electronics industry caused serious problems to both humans as well as environment in the
surrounding. Therefore, wastewater from the electronics industry should be treated
efficiently and industries should try to make reuse of water generated from the various
manufacturing processes.

4
1.4 Objective of the Study
The main objective of the study is to calculate the design parameters which affect the
efficiency of the wastewater treatment systems in the electronics industry. Working of these
parameters will point out the environment management system to be adopted for the
treatment of waste.
The specific aims of the study are to:
• To experimentally check the adequacy and efficacy of various treatment processes by
calculating design parameters at different points.
1.5 Scope of the Study
This study focuses on types of treatment processes used by the concerned electronic Industry
in treating the effluent wastewater. The efficiency of these processes needs to be known for
better management and disposal of waste. Study aims to suggest positive changes, if any, in
the processes for attaining the maximum efficiency.
Area of the Study- An effluent treatment plant of a reputed MNC in the field of electronics
manufacturing is chosen. This company is in electronics manufacturing field in India since
90s. A wide variety of electrical and electronics components are being manufactured in this
plant facility. Due to various products and processes involved in the manufacturing at this
plant facility it is found to be good for our experimental work. For the treatment of
wastewater this plant has 2 treatment facilities-
 Effluent Treatment Plant (ETP)
 Sewerage Treatment Plant (STP)
For our experimental study ETP is chosen as it would contain the wastewater from the
manufacturing units involving wide variety of waste materials.
Unit Processes in the Effluent Treatment Plant: Various unit processes involved in the
treatment plant are as follows:

5
 Skimming Tank
 Primary Clarification
 Equalization
 Activated Sludge Process
 Secondary Clarification
 pH Correction
 Filtration
Parameters considered in the experimental study: Various Parameters calculated in this
study are as follows:
 pH
 Conductivity
 Total Dissolved Solids
 Total Suspended Solids
 Dissolved Oxygen
 Biological Oxygen Demand
 Chemical Oxygen Demand
 Ammonical Nitrogen
 Phosphate
 Oil and Grease
 Heavy Metals
These parameters are calculated at different stages of treatment plants.

6
CHAPTER 2
LITERATURE REVIEW
Wastewater treatment can be defined by physical, chemical, and biological processes. Physical
parameters include color, odor, temperature, solids (residues), turbidity, oil, and grease.
Chemical parameters associated with the organic content of waste water include the biochemical
oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), and total
oxygen demand (TOD). Inorganic chemical parameters include salinity, hardness, pH, acidity,
alkalinity, iron, manganese, chlorides, sulfates, sulfides, heavy metals (lead, chromium, copper,
and zinc), nitrogen (organic, ammonia, nitrite, and nitrate), and phosphorus whereas the
bacteriological parameters include coliforms, fecal coliforms, specific pathogens, and viruses.
Electronics Industry Waste
The wastewater from electronics industries varies so greatly in both flow and pollution strength.
So, it is impossible to assign fixed values to their constituents. In general, wastewaters may
contain suspended, colloidal and dissolved (mineral and organic) solids. In addition, they may be
either excessively acid or alkaline and may contain high or low concentrations of colored matter.
Abdulrzzak Alturkmani (2013) has found that heavy metals like nickel, zinc, chromium and
cadmium are commonly found in the industries manufacturing electronics components.
According to World Bank group (2007) the electronics industry includes the manufacture of
passive components (resistors, capacitors, inductors); semiconductor components (discrete,
integrated circuits); printed circuit boards (single and multilayer boards); and printed wiring
assemblies. They also found that Effluents from the manufacture of semiconductors may have a
low pH from hydrofluoric, hydrochloric, and sulfuric acids (the major contributors to low pH)
and may contain organic solvents, phosphorous oxychloride (which decomposes in water to form
phosphoric and hydrochloric acids), acetate, metals, and fluorides. Effluents from the
manufacture of printed circuit boards may contain organic solvents, vinyl polymers; stannic
oxide; metals such as copper, nickel, iron, chromium, tin, lead, palladium, and gold; cyanides
(because some metals may be complexed with chelating agents); sulfates; fluorides and

7
fluoroborates; ammonia; and acids. Effluents from printed wiring assemblies may contain acids,
alkalis, fluxes, metals, organic solvents, and, where electroplating is involved, metals, fluorides,
cyanides, and sulfates.
Impact of electronics industries on the downstream of a river:
Electronics industries located near to the river poses greater damage to aquatic life as well as
human life. Heavy metals from these industries become life threatening to the aquatic species
and severely affect the quality of wastewater. Angela Yu-Chen Lin*, Sri Chandana
Panchangam, Chao-Chun Lo (2008) conducted study on the influence of the semiconductor
and electronics industries on per fluorinated chemicals (PFCs) contamination in receiving rivers.
The distribution of PFCs in the receiving rivers was greatly impacted by industrial sources. Their
results suggest that these manufacturing facilities, located directly upstream of our sampling
spots, are the primary causes of PFC contamination in the Keya, Touchien, and Xiaoli rivers.
The Keya River in particular was found to be polluted with PFCs derived from effluents out of
Hsinchu Science Park (HSP). A plausible risk to human and aquatic life exists, as demonstrated
directly by the quantity of PFCs detected in these rivers and indirectly by the many drinking
water intake sites situated downstream of our sampling points.
Important parameters in the effluent treatment plant
There are many parameters which affects the efficiency of a treatment plant. A study conducted
by Megha S.Kamdi1, Isha.P.Khedikar ², R.R.Shrivastava (2012) in which they have determined
the physical and chemical parameters of the waste water or the effluent, at inlet and outlet of the
effluent treatment plant. Under this study the various parameters such as temperature, pH,
chemical oxygen demand(COD), suspended solids(SS), total dissolved solids(TDS), phosphorus
and heavy metals are determined by taking samples at inlet and outlet of effluent treatment plant
and compared with the Indian standards for effluent discharge into river. The variation in the
parameters at inlet observed to be, 7.4-7.9 for pH, 40-90 for COD and 180-70 for SS and at
outlet it is 7.1-7.5 for pH, 32- 68 for COD and 42-95 for SS. The average performance efficiency
of the plant is calculated for the period of study & observed to be 26.85% for COD, 26.69% for
TDS, 15.51% for Phosphate, and 22.81% copper.

8
In a book series written by Mohidus Samad Khan, Jerry Knapp, Alexandra Clemett,
Matthew Chadwick, Mahbub Mahmood and Moinul Islam Sharif, it is mentioned the
importance of the evaluation of ETPs and their monitoring. They said that by law factories must
monitor the quality of their wastewater and stay within national limits for pollution. The
Environment Conservation Rules should provide national standards for the quality of industrial
wastewater being discharged into certain places including open water bodies, public sewers and
irrigated land. They should also provide specific discharge quality standards for key parameters
from certain industries. It is also necessary and useful to monitor these parameters in the
wastewater entering the ETP and at several stages in the ETP process. This enables the ETP
manager to optimize the ETP process by adjusting chemical inputs, retention time and other
factors. This can reduce costs by preventing excess chemicals from being used and will result in
a more efficient plant that produces effluent that complies with national standards. Good ETP
management therefore requires a certain level of understanding of the overall function of the
ETP, how individual units work, how to monitor their functioning, and how to diagnose and
address problems. And the parameters to be checked are BOD, COD, DO, TDS, TSS, etc.
Performance evaluation of common effluent treatment plants:
Anju Singh, Richa Gautam and Swagat Kishore Mishra (2010) conducted a study on the
performance of a CETP treating 3405 m3 day-1 wastewater from 450 synthetic textile mills.
Four criteria viz. design, operation, maintenance and administration was deployed to evaluate the
overall performance of CETP. Design data was collected from each unit operation of the CETP
and adequacy of design was assessed using a scoring method. They have suggested some
improvements like better mixing in equalization tank, modifications in HRT, SOR etc. in the
clariflocculator, increasing HRT in aeration tank, can be achieved by changing operational
parameters. The Lime and FeSO4 tanks have inadequate capacity and mixing which therefore
needs improvement. Existing sludge drying beds are only 27% of the area required and therefore
need further construction. The COD and BOD in the outlet exceeded the standards for effluents
from textile industries. The two aeration tanks need to improve in terms of performance. This
can be achieved by improving the biomass in the aeration tanks I and II and increasing the HRT.

9
Other standards were met by the treated effluents. These parameters are important in the
calculation of efficiency of the treatment plant.
In an another study conducted by Gautam, S.P, Bundela, P.S. Kapoor, A. Awasthi, M.K.
Sarsaiya, S (2010). They identified the sources of wastewater generation and their approximate
quantities were estimated. Representative wastewater samples were collected from different
location of effluent treatment and brought to the laboratory for analysis of various environmental
parameters such as pH, BOD, COD, TSS, YDS and oil and Greece as per the standard methods.
The performance of ETP was evaluated by assessing the performance of each component based
on the pollution load, the required treatment efficiency and the monitoring results. The
characteristics of treated wastewater at final outlet of ETP are compared with discharge standard.
The characteristics of treated wastewater at final outlet of plant are compared with desired
characteristics of treated waste to be used in the process. Based on the pollution load on ETP and
required capacity of its each component adequacy of respective component of existing ETP has
been assessed. Further, the wastewater samples were collected and analyzed for inlet outlet of all
the ETP components to assess its efficacy. In the results, ETP failed to comply with the standards
and didn’t find efficient.
DIPALI H. CHAIUDHARI and R.M. DHOBLE (2010) have conducted a study on the
performance evaluation of effluent treatment plant of dairy industry. They have collected
samples from forth points; Raw effluent [P-1], Equalization tank [P-2], Aeration tank [P-3],
Oxidation ditch [P-4] to evaluate the performance of ETP. Parameters analyzed for evaluation of
performance of ETP are pH, COD, BOD at 27° C, TSS. The COD, BOD and TSS removal
efficiency of ETP was observed to be 94%, 95% and 93% respectively in spite of the fact that
raw sewage. BOD: COD ratio was 0.5. The performance of ETP is in terms of average change
(%) in the pollution parameters. % efficiency is given in average efficiency of aeration tank and
oxidation ditch. Efficiency of units (Aeration tank and oxidation ditch) is found out in terms of
percentage. The BOD/COD ratio of the industrial effluent is more than 0.6, it is biologically
treatable. If the BOD/COD ratio is less than 0.3 biological treatments is not necessary. Biological
treatment methods is used in this plant i.e. Oxidation Ditch.

10
Heavy metals in wastewater:
The most commonly encountered toxic heavy metals in wastewater: Arsenic, Lead, Mercury,
Cadmium, Chromium, Copper, Nickel, and Zinc. Their source varies from Industrial sources
like Printed board manufacturing, metal finishing and plating, semiconductor manufacturing,
textile dyes, etc. Many heavy metals are essential trace elements for humans, animals and plants
in small amounts. In larger amounts they can cause acute and chronic toxicity. Heavy metals
have inhibitory effects on the biological treatment process at the wastewater treatment plants.
Activated sludge process does not remove most of the heavy metals efficiently. Heavy metals do
not disappear nor react – they are either in the water or in the sludge.
Asli Baysal, Nil Ozbek and Suleyman Akman determined the Trace Metals in Waste Water and
Their Removal Processes. They have described the Atomic Absorption Spectrometry as an
analytical method for quantification of over 70 different elements in solution or directly.
Procedure depends on atomization of elements by different atomization techniques like flame
(FAAS), electrothermal (ETAAS), hydride or cold vapor. According to them precipitation is the
most common method for removing toxic heavy metals up to parts per million (ppm) levels from
water. Since some metal salts are insoluble in water and which get precipitated when correct
anion is added. Ion exchange is another method used successfully in the industry for the removal
of heavy metals from effluents. Though it is relatively expensive as compared to the other
methods, it has the ability to achieve ppb levels of clean up while handling a relatively large
volume.
Rafiquel Islam, Jannat Al Foisal, Hasanuzzaman, Musrat Rahman, Laisa Ahmed Lisa and
Dipak Kumar Paul on their study on Pollution assessment and heavy metal determination by
AAS in waste water collected from Kushtia industrial zone in Bangladesh analyzed the Pb, Cd,
Cr, Cu and Mn heavy metals. The results indicate that the concentration of Mn (0.68 to 0.72
ppm) exceeded the standards, although Pb and Cu were found within the standard limit at 0.0045
to 0.0085 and 1.33 to 1.58 ppm, respectively. Interestingly, contamination of Cd and Cr

11
identified were below detective level. This study points out the health risk status of waste water
for residents and aquatic living being, an ultimate concern for their survival in the region.
Mass balance concept in the treatment plant:
A mass balance is an accounting of a material for a specific system boundary. In other words, we
are keeping track of all sources of the material that enter the system, all sinks of the material that
leave the system, and all storage of the material within the system. A mass balance can be done
for four scenarios or combinations of those scenarios as follows:
 Dynamic (flows change over time)
 Steady State (flows do not change over time; the system is in equilibrium)
 Conservative pollutants (the pollutant does not change form over time; no reactions)
 Non-conservative pollutant (the pollutant changes form over time due to chemical,
physical, or biological reactions)
In a study conducted by Athar Hussain, Pradeep Kumar, Indu Mehrotra (2009) titled Nitrogen
biotransformation in anaerobic treatment of phenolic wastewater a nutrient mass balance was
done. The change in feed N is reflected proportionately in the effluent-N. The stoichiometric
nitrogen requirement for growing cells has been reported to range from 6 to 12%. The anaerobic
microbial cells (C5H7O3N) contain 11% N and 2.2% P; the experimental determinations are
close to the cell formulation reported by Rittman and McCarty. They have found that additional
nitrogen might be coming from cell-lyses or cell. Decay of cells is expected to release 11% of
nitrogen. A decay rate of 6.5 × 10−3 d−1 gives nitrogen which accounts for (i) 80% of nitrogen
in the effluent and (ii) nitrogen required for is 3.5% cell yield.
In an another study conducted by N. Gans, S. Mobini and X. N. Zhang named Mass and Energy
Balances at the Gaobeidian Wastewater Treatment Plant in Beijing, China, mass and energy
balances are carried out for the Gaobeidian wastewater treatment plant in Beijing, China, in order
to identify the needs for process optimization and energy conservation. The mass balance over
the sludge treatment was carried out both on theoretical values and based on measured values.
Due to a lack of information it was only calculated for SS. Mass balances are valuable tools for

12
investigating the general performance of a wastewater treatment plant and an effective method to
assess the reliability of the available data. In the case of the Gaobeidian WWTP, the mass
balance calculations based on measured values suggest that there might be problems with the
measurements. From the mass balance over the Gaobeidian WWTP it could be concluded that
the present nutrient removal is not optimal and the sludge treatment seems to be overloaded.
Methods for the optimisation of the plant should therefore focus on these problems.

13
CHAPTER 3
TREATMENT PLANT DESCRIPTION
3.1 Design Basis
The following characteristics have been considered for the design of the inlet and outlet
parameters of the Effluent Treatment Plant:
Sr. No. Parameter Inlet Outlet
1 Flow (m3
/hr) 10 10
2 pH 7-8 7-8
3 Fe (ppm) 32.11 <3
4 Zn (ppm) 277.2 <5
5 Mn (ppm) 6.2 <2
6 Pb (ppm) 3 <0.1
7 Cu (ppm) 0.3 <3
(Table: 3.1 Design basis parameters)

14
3.2 Flow Diagram of the treatment Plant
C BUILDING
COLLECTION
TANK
SKIMMING
TANK
AERATION
TANK
REACTION
TANK
PRIMARY
CLARIFIER
HOLDING
TANK
EQUALIZATION
TANK
MULTI GRADE
FILTER
pH
CORRECTION
TANK
SECONDARY
CLARIFIER
OUTLET
Sludge

15
(Figure: 3.1 effluent treatment plant)
(Figure: 3.2 way to secondary clarifier in the ETP)

16
3.3 Technical Data
Technical Data of the treatment plant is summarized below in a table:
Sr. No. Description Size/Capacity Quantity Make
1 Collection cum oil removal
tank
4.2m x 0.5m x 1.0m 1 No. RCC
2 Equalization tank 4.5m x 4.0m x 3.5m 1 No. RCC
3 pH tank 3.5m x 1.0m x 1.8m 1 No. RCC
4 Sludge sump 2.5m x 2.5m x 1.6m 1 No. RCC
5 Lime dosing tank 1.4m x 1.5m x 1.6m 2 No. RCC
6 Oil collection tank 1 m3
1 No. MS
7 Fume absorber - 1 No. MSRL
8 Sludge transfer Pumps 5 m3
/ hour @10 MWC 2 No. CI
9 Reaction tank 2.0 m x 1.8m x 1.6m 1 No. RCC
10 Multi grade filter 1.0 dia x 23 m H.O.S 1 No. MS
11 Pipe oil skimmer 80 NB x 500 mm long 1 No. MSEP
12 High rate solids contact
clarifier grade mechanism
Suitable for 4.0 m dia 2 No. MSEP
13 Air compressor 0.25 m3
/ hr 2 No. CI
14 Coagulant dosing pumps 0-50 lph 2 No. PP
15 Centrifuge 5 m3
/ hr 1 No. CI
(Table: 3.2 Technical data of the treatment plant)

17
CHAPTER 4
MATERIALS AND METHODS
4.1 Sampling and Sample Preservation-
During our experimental work different experiments were performed to calculate various
parameters which affect the efficiency of the effluent treatment plant. All the experiments
were performed according to the standard procedure established by the regulatory bodies.
Instruments used in the experiments were from the reputed companies and comply with the
necessary standards. All necessary precautions were taken while performing the experiments.
Grab sampling has been done at different points of the treatment plant. One litre new PVC
bottles were used for all samples taken. Sample bottles were securely sealed following
sampling and stored securely. The wastewater sample preserved to about 4 degrees Celsius.
This refrigeration maintains the biochemical oxygen demand. Samples were protected from
direct heat and sunlight so as to reduce as the interferences as much as possible.
4.2 Materials and Methods used in the determination of various parameters-
List of various parameters and their determination methodology is given below-
4.2.1 pH-
In simple words, pH is a logarithmic measurement of hydrogen ion concentration. pH has
direct influence on wastewater treatability — no matter which treatment it is physical,
chemical or biological. A very low pH value requires less contact time as compared to a
higher pH value. Different chemicals have different reaction times, which further have a
major effect on pH. To minimize corrosion, optimum pH levels of the pH should be
maintained.
Method: Electrometric Method

18
Instrument: Hach Portable Meter Package with pH electrode
Materials Required: pH Probe, Beaker, Measuring Cylinder, Tissue Paper
4.2.2 Electrical Conductivity
Electrical Conductivity (EC) is the measure of the ability with which water conducts
electricity in the wastewater. Different salts in water have a different capacity to conduct
electricity. This is due to the differences in charge and size and mobility of the different
ions. Electrical conductivity also gives an indication of the total dissolved salt (TDS)
content of the water. This is because EC is a measure of the ionic activity of a solution in
term of its ability to transmit current. In most of the dilute solution, TDS and EC are
comparable.
Method: Direct Conductivity Method
Instrument: Hach Portable Meter Package
Materials Required: EC Probe, Beaker, Measuring Cylinder, Tissue Paper
4.2.3 Dissolved Oxygen (DO)
Dissolved oxygen is a molecule of oxygen that is dissolved into the wastewater. It is
affected by the temperature. If the temperature of the water is high, DO concentration
will be less. And also if the plants population is high in the stream then also DO levels
will be lower. Various scientific studies suggested that 4-5 parts per million (ppm) of DO
is the minimum amount that should be present. In the activated sludge process a
minimum level of 6 ppm of DO should be present for the microorganisms.
Method: Direct DO Probe Method
Materials Required: DO Probe, Beaker, Measuring Cylinder, Tissue Paper

19
4.2.4 Total Dissolved Solids (TDS)
Total Dissolved Solids is the amount of charged ions (minerals salts or metals) dissolved
in a given volume of water sample. It is directly related to the purity of water and quality
of purification systems. In general, the total dissolved solids are the sum of cations and
ions in any wastewater sample. Total dissolved solids are based on the electrical
conductivity of water. Pure water has almost zero conductivity. Some dissolved solids
come from organic sources; other comes from runoff at the streets. Solids also come from
inorganic materials such as rocks. Salts usually dissolve in water forming ions that can be
negative or positive.
Method: Direct TDS Method
Materials Required: TDS Probe, Beaker, Measuring Cylinder, Tissue Paper
(Figure: 4.1 Hach Portable Meter)

20
4.2.5 Total Suspended Solids (TSS)
Total Suspended solids are solid materials that are suspended in the water. High
concentrations of these suspended solids can lower the water quality by absorbing more
light. Suspended solids can result from surface runoff, bank erosion, algae growth.
Method: Filter Paper Method
Materials Required: Beakers, Measuring Cylinder, Weighing Balance, Oven, Glass Filter
paper, and Desiccator.
Procedure:
 Initially dry the filter in oven at 103-105 degree Celsius for 1 hour.
 Place Filtration apparatus with weighed filter in filter disk.
 Mix sample well and pour into a cylinder up to a known volume.
 Pour the known volume in the filter flask.
 Draw sample into the flask through the filter.
 Rinse the cylinder with successive 10 ml portions and continue suction after the
last rinsing.
 Dry filter in oven at 103-105 degree Celsius for 1 hour.
 Cool the filter paper in the desiccator and weigh.
Total suspended solids (mg/L) = (A-B) X 1000/sample volume, mL
where:
A = weight of filter + dried residue (mg)
B = weight of filter (mg)
4.2.6 Mixed Liquor Suspended Solids (MLSS)
Mixed liquor in the treatment plant is a combination of sludge and water from the
clarifier in the treatment process. It is reintroduced into an earlier phase of the treatment
process. The mixed liquor contains microorganisms which digest the wastes in the raw
wastewater.
Mixed Liquor Suspended Solids is a test for the TDS in a sample of mixed liquor.
Method: Filter Paper Method

21
Materials Required: Beakers, Measuring Cylinder, Weighing Balance, Oven, Glass Filter
paper, and Desiccator.
Procedure: This test is essentially the same as the test we performed for TSS in the last
step except for the use of mixed liquor as the water sample.
4.2.7 Oil and Grease
Oil and grease causes ecology damages for aquatic organisms and equally, mutagenic and
carcinogenic for human being. They discharge from different sources to form a layer on
the water surface that decreases DO. This layer reduces biological activities in the
treatment processes. This lead to decrease dissolved oxygen levels in the water. Also due
to this oxygen molecules are difficult to be oxidative for microbial on hydrocarbon
molecules. The conventional techniques of removal make use of skimming tanks and oil
and grease traps in treatment plants but their efficiency of removal is quite low.
Materials Required: Beakers, Measuring Cylinder, Weighing Balance, n- Hexane,
Hydrochloric acid, Filter paper, Desiccator, Water bath.
Procedure:
Transfer the sample to a separating funnel. Carefully rinse the sample bottle with 30 ml
of n-Hexane and add the solvent washings to the separating funnel. Shake for 2 minutes.
Let the layers separate. Drain the solvent layer through a funnel containing solvent
moistened filter paper into a clean distillation flask. Extract two more times with 30 ml of
solvent each time, but first rinse the sample container with the solvent. Collect the
extracts in a clean distillation flask and wash filter paper with an additional 10 to 20 ml of
the solvent. Distil solvent from distillation flask over a water bath at 70°C. Quantitatively
transfer the residue using a minimum quantity of solvent into a clean, dried beaker. Place
the beaker on water bath for 15 minutes at 70°C and evaporate off all the solvents. Cool
the beaker in a desiccator for 30 minutes and weigh.
Oil and Grease (mg/l) = (M / V) x 1000
where,

22
M= Mass in mg of the residue
V = Volume of the sample
(Figure: 4.2 Oil and Grease determination)
4.2.8 Sludge Volume Index
Sludge Volume Index (SVI) is a very important indicator that determines your control or
rate of de-sludging and it is calculated by considering the volume, in milliliters, of 1 gram
of suspended solids after 30 minutes of settling. It actually serves as a very important
measurement that can be used as a guide to maintain sufficient concentration of activated
sludge in the aeration tank whereby too much or too little can be considered problematic
to the system’s overall health.
Materials Required: Beakers, Graduated Measuring Cylinder of 1L capacity.

23
Procedure:
 Obtain sample of mixed liquor and fill it to a 1 liter graduated measuring cylinder
until the 1.0 liter marking.
 Allow it to settle for 30 minutes.
 After the time period, read the marking to determine the volume occupied by the
settled sludge.
 The reading of the settled sludge is expressed in terms of mL/L. This is known as
SV value.
SVI = (SV / MLSS) x 1000
4.2.9 Biological Oxygen Demand (BOD)
BOD determination is an empirical test in which relative oxygen demand is determined
over a period of five days at 20 degree Celsius. Another method is to determine BOD for
a period of 3 days at 27 degree Celsius. In general, it is the amount of dissolved oxygen
demanded by aerobic organisms to break down organic material present in a given
wastewater sample. BOD directly affects the amount of Do in rivers and streams. The
rate of oxygen consumption is affected by a number of factors like temperature, pH and
the presence of certain kinds of microorganisms. The greater the BOD, the more rapidly
oxygen is depleted in the stream.
Apparatus and Reagents:
 Incubation bottles or BOD bottles
 Incubator
 Deionized water
 Hach Glucose And Glutamic Acid solution
 Nutrient buffers

24
Procedure:
 To ensure proper biological activity during the BOD test, a wastewater sample:
o Must be free of chlorine. If chlorine is present in the sample, a chlorination
chemical (sodium sulfite) must be added prior to testing.
o Needs to be in the pH range of 6.5-7.5.
 Add approximately 30 mL of deionized water to a 200 mL graduated cylinder.
 A seed solution of bacteria is added along with an essential nutrient buffer solution
that ensures bacteria population vitality.
 Dilute to the sample to 160 mL using deionized water wash bottle.
 Specialized 300 mL BOD bottles designed to allow full filling. At least one bottle is
filled only with dilution water as a control or blank.
 Measure the initial DO content in the BOD bottles.
 Each bottle in then placed into a dark incubator at 20°C for five days.
 After five the DO meter is used again to measure a final dissolved oxygen
concentration (mg/L).
 The final DO reading is then subtracted from the initial DO reading and the result is
the BOD concentration (mg/L). If the wastewater sample required dilution, the BOD
concentration reading is multiplied by the dilution factor.
Dilution factor = Bottle volume (300 ml) / Sample Volume
BOD (mg/L) = DO (Initial – Final) x dilution factor

25
(Figure: 4.3 Seeds and BOD bottles in the Incubator)
4.2.10 Chemical Oxygen Demand (COD)
COD is a measure of the capacity of water to consume oxygen during
the decomposition of organic matter and the oxidation of inorganic chemicals such
as ammonia and nitrite. It is the amount of oxygen equivalent of dichromate, a specified
oxidant that reacts with the sample under controlled conditions. A commonly used
oxidant in COD assays is potassium dichromate (K2Cr2O7) which is used in combination
with boiling sulphuric acid.
 Borosilicate culture tubes with screw caps
 Block Heater
 Spectrophotometer for use at 600 nm.
 Digestion Solution (0.1 K2Cr2O7 + H2SO4)
 H2SO4 Reagent

26
 Potassium Hydrogen phthalate: Dissolve 425 mg in 1 L DW
Procedure:
 Prepare standards of COD ranging from 100-500 µg/ml.
 Transfer 2.5 mL of sample and standards to culture tubes.
 Add 1.5 mL digestion solution and 3.5 mL H2SO4 Reagent.
 Place cultural tubes in block digester preheated at 150 degree and reflux for 2
hours.
 Cool sample and standards to room temperature slowly.
 Measure absorbance of sample and standards at 600 nm.
(Figure: 4.4 COD Block heater and spectrophotometer)
4.2.11 Ammonical Nitrogen
Ammonical nitrogen (NH3-N), is a measure for the amount of ammonia, a
toxic pollutant often found in the wastewater. The values of ammonical nitrogen in water
or waste liquids are measured in milligram per liter and are used for specifying water

27
treatment systems and facilities. It can also be used as a measure of the health of water in
natural bodies such as rivers or lakes, or in man-made water reservoirs.
 Spectrophotometer at 410 nm.
 Beakers, Volumetric Flask
 Standard Ammonical Solution
 Nessler Reagent (mercury iodide + potassium iodide)
 EDTA
Procedure:
 Standard solution of 1,2,3,4,5 and 6 mg/L are prepared in 50 mL of Nessler tube.
 50 mL sample is taken in Nessler tube.
 2 mL of Nessler reagent was added into standard and sample both.
 2 or 3 drops of EDTA indicator is added.
 Leave the sample for 30 minutes for color development.
 Absorbance was taken at wavelength 410 nm.
4.2.12 Phosphate
Phosphorous occurs in natural waters as orthophosphate, condensed phosphates and
organic bound phosphates. They occur in solution, in particles or bodies of aquatic
organisms. They are used in treatment of boiler feed waters. They are found in sewage or
wastewater due to body wastes and food residues.
 Spectrophotometer at 690 nm.

28
 Beakers, Volumetric Flasks.
 Strong acid solution
 Ammonium molybdate solution
 Stannous chloride solution
 Standard phosphate solution
Procedure:
 Take 6 tubes and add standard phosphate. Add distilled water to make upto 100
mL. Take 100 mL of the sample or a portion of it and dilute it with distilled water
to 100 mL.
 Add 4 mL ammonium molybdate solution, 10 drops of stannous chloride solution
and mix well.
 Leave for 10 minutes and record the absorbance at 690 nm.
4.2.13 Heavy Metals
Due to the discharge of large amounts of industries wastewater, metals such as Cd, Cr,
Cu, Ni, As, Pb, and Zn, are found in the water. Because of their high solubility in the
aqueous environments, heavy metals can be absorbed by living organisms too. They can
cause serious health issues if enters our food chain. Heavy metal removal from inorganic
effluent can be achieved by conventional treatment processes such as chemical
precipitation, ion exchange, and electrochemical removal.
In our experimental study we have determined five heavy metals – Arsenic, Selenium,
Lead, Iron and Chromium from atomic absorption spectroscopy.
Instrument and Reagents:
 Atomic absorption spectroscopy
 Volumetric flasks, Beakers
 3% HCL

29
 Standard solutions of Arsenic, Selenium, Lead, Iron and Chromium
Procedure:
 Standard solutions of all heavy metals are made in the range of 0ppm, 0.5ppm,
1.0ppm, 3.0ppm and 5.0ppm
 Each heavy is found out using flame technology.
 Blank correction is applied at the initial stage and at the end of the standards.
 Data is recorded and calibration curve is plotted.
 Actual concentration of the heavy metals is calculated.
(Figure: 4.5 Atomic Absorption Spectroscopy)

30
8.89
7.34 7.27
6.82
5
6
7
8
9
Inlet Equalization Tank Secondary Clarifier Outlet
pH
Sampling Point
CHAPTER 5
RESULTS & DISCUSSIONS
5.1 Determination of parameters at different locations:
Different parameters were calculated at four locations: Inlet, Equalization Tank, Secondary
Clarifier and Outlet. Readings were depicted below at all the locations.
5.1.1 pH
Sr. No. Sampling Point Method Observed Value
1 Inlet Electrometric method 8.89
2 Equalization Tank Electrometric method 7.34
3 Secondary Clarifier Electrometric method 7.27
4 Outlet Electrometric method 6.82
(Table 5.1.1: pH)
(Figure 5.1.1: pH values)

31
5.1.2 Electrical Conductivity
Sr. No. Sampling Point Method Observed Value
(µS/cm)
1 Inlet Direct Method 1189
2 Equalization Tank Direct Method 1136
3 Secondary Clarifier Direct Method 1132
4 Outlet Direct Method 955
(Table 5.1.2: Electrical Conductivity)
(Figure 5.1.2: Electric Conductivity values)
1189
1136
1032
955
950
1000
1050
1100
1150
1200
EC(µS/cm)
Sampling Point

32
5.1.3 Dissolved Oxygen
Sr. No. Sampling Point Method Observed Value (mg/L)
1 Inlet DO Meter 5.48
2 Equalization Tank DO Meter 4.66
3 Secondary Clarifier DO Meter 7.38
4 Outlet DO Meter 7.57
(Table 5.1.3: Dissolved Oxygen)
(Figure 5.1.3: Dissolved Oxygen values)
5.48
4.66
7.38 7.57
0
1
2
3
4
5
6
7
8
DO(mg/L)
Sampling Point

33
5.1.4 Total Dissolved Solids
1 Inlet Direct Method-TDS Meter 589
2 Equalization Tank Direct Method-TDS Meter 449
3 Secondary Clarifier Direct Method-TDS Meter 271
4 Outlet Direct Method-TDS Meter 188
(Table 5.1.4: Total Dissolved Solids)
(Figure 5.1.4: Total Dissolved Solids values)
589
449
271
188
100
150
200
250
300
350
400
450
500
550
600
TDS(mg/L)
Sampling Point

34
5.1.5 Total Suspended Solids
Total suspended solids (mg/L) = (A-B) X 1000/sample volume
where:
A = weight of filter + dried residue (mg)
1 Inlet Filter paper Method 239
2 Equalization Tank Filter paper Method 216
3 Secondary Clarifier Filter paper Method 156
4 Outlet Filter paper Method 89
(Table 5.1.5: Total Suspended Solids)
(Figure 5.1.5: Total Suspended Solids values)
239
216
156
89
50
70
90
110
130
150
170
190
210
230
250
TSS(mg/L)
Sampling Point

35
5.1.6 Biological Oxygen Demand
BOD (mg/L) = DO (Initial – Final - Blank) x dilution factor
1 Inlet Respirometric Method 160.44
2 Equalization Tank Respirometric Method 132.91
3 Secondary Clarifier Respirometric Method 79.38
4 Outlet Respirometric Method 38.65
(Table 5.1.6: BOD values)
(Figure 5.1.7: BOD values)
160.44
132.91
79.38
38.6530
50
70
90
110
130
150
170
BOD(mg/L)
Sampling Points

36
5.1.7 Chemical Oxygen Demand
1 Inlet UV Spectrophotometer 267.33
2 Equalization Tank UV Spectrophotometer 201.05
3 Secondary Clarifier UV Spectrophotometer 148.68
4 Outlet UV Spectrophotometer 72.31
(Table 5.1.7: COD values)
(Figure 5.1.7: COD values)
267.33
201.5
148.6
72.3
50
100
150
200
250
300
COD(mg/L)
Sampling Point

37
5.1.8 Ammonical Nitrogen
(Table 5.1.8: Ammonical Nitrogen values)
(Figure 5.1.8: Ammonical Nitrogen values)
1
0.735
0.249
0.127
0
0.2
0.4
0.6
0.8
1
1.2
Am.Nitrogen
(mg/L)
Sampling Point

38
5.1.9 Phosphate
(Table 5.1.9: Phosphate values)
(Figure 5.1.9: PO4 values)
0.775
0.624
0.349
0.201
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
PO4(mg/L)
Sampling Point

39
5.1.10 Oil and Grease
Oil and Grease (mg/l) = (M / V) x 1000
where,
M= Mass in mg of the residue
V = Volume of the sample
1 Inlet n-Hexane Method 7.289
2 Outlet n-Hexane Method 1.251
(Table 5.1.10: O&G values)
(Figure 5.1.9: O&G values)
7.289
1.251
0
1
2
3
4
5
6
7
8
Inlet Outlet
O&G(mg/L)
Sampling Point

40
5.1.11 Heavy Metals
a. Arsenic
Sr. No. Sampling Point Method Observed Value (ppm)
1 Inlet AAS – Flame 0.423
2 Outlet AAS - Flame 0.264
(Table 5.1.11.a: Arsenic values)
(Figure 5.1.11.a.: Arsenic values)
b. Lead
(Table 5.1.11.b: Lead values)
0.423
0.264
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Inlet Outlet
Ar(ppm)
Sampling Point

41
(Figure 5.1.11.b.: Lead values)
c. Iron
(Table 5.1.11.c: Iron values)
(Figure 5.1.11.c.: Iron values)
0.321
0.205
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Inlet Outlet
Pb(ppm)
Sampling Point
3.074
0.417
0
0.5
1
1.5
2
2.5
3
3.5
Inlet Outlet
Fe(ppm)
Sampling Point

42
d. Selenium
1 Inlet AAS – Flame Not detected
2 Outlet AAS - Flame Not detected
(Table 5.1.11.d.: Selenium values)
e. Chromium
(Table 5.1.11.e.: Chromium values)
(Figure 5.1.11.e.: Chromium values)
0.253
0.003
0
0.05
0.1
0.15
0.2
0.25
0.3
Category 1 Category 2
Cr(ppm)
Sampling Point

43
5.2 Determination of various design parameters involved in the Activated
Sludge Process:
5.2.1 Mixed Liquor Suspended Solids
It is given by-
MLSS (mg/L) = (A-B) X 1000,000/sample volume (L)
where:
A = weight of filter + dried residue after muffle furnace (mg)
MLSS = 0.00314 x 106
= 3140 mg/L
1
Also, MLVSS = 0.75 x MLSS = 2355 mg/L
5.2.2 Sludge Volume Index
It is given by-
SVI = (SV / MLSS) x 1000
SVI = 402 x1000 / 3140 = 128 (mL/g)
5.2.3 Yield Coefficient
Yield coefficient (Y) Y = 0.1 g VSS g = 0.1 x 60 = 0.492
BOD removed (121.79)
5.2.4 Substrate concentration
S = 1 (1/qc + kd)
qY

44
= 1 (1/5 + 0.07) = 14.50 mg/ L
(0.038 x 0.492)
5.2.5 Volume of the Aeration Tank:
VX = YQqc(SO - S)
1+ kdqc
where, X = 0.8(3140) = 2512 mg/l
2512 V = (0.49)(5)(240)(112-14.5)
[1 + (0.07)(5)]
V = 78 m3
5.2.6 F/M:
F/M = QSO / XV
= (112-14.5) x 240 = 0.101 kg BOD5 per kg MLSS per day
3140 x 78
5.2.7 Detention Period: t = 78 x 24 = 7.2 h
240
5.2.8 Return Sludge Pumping:
R = MLSS = 0.45
(10000)-MLSS
Qr = 0.45 x 240 = 108 m3
/d

45
5.3 Removal Efficiency of the treatment plant:
5.3.1 BOD Removal Efficiency
It is given by –
BOD (inlet) – BOD (Outlet) x 100 = (160.44- 38.65) x100
BOD (inlet) 160.44
= 75.90%
BOD removal efficiency of primary clarifier = 160.44 – 120.21 x100 = 25.4 %
160.44
BOD removal efficiency of primary clarifier = 110.01 – 79.38 x100 = 31.8 %
110.01
5.3.2 COD Removal Efficiency
It is given by –
COD (inlet) – COD (Outlet) x 100 = (267.33- 72.31) x100
COD (inlet) 267.33
= 72.95%
5.3.3 TDS Removal Efficiency
It is given by –
TDS (inlet) – TDS (Outlet) x 100 = (589- 188) x100
TDS (inlet) 589
= 68.08%

46
5.3.4 TSS Removal Efficiency
It is given by –
TSS (inlet) – TSS (Outlet) x 100 = (239- 89) x100
TSS (inlet) 239
= 62.76%
5.3.5 Oil and Grease Removal Efficiency
It is given by –
O&G (inlet) – O&G (Outlet) x 100 = (7.289- 1.25) x100
O&G (inlet) 7.289
= 82.85%
5.3.6 Ammonical Nitrogen Removal Efficiency
It is given by –
N (inlet) – N (Outlet) x 100 = (1.00- 0.127) x100
N (inlet) 1
= 87.30%
5.3.7 Orthophosphate Removal Efficiency
It is given by –
P (inlet) – P (Outlet) x 100 = (0.775-0.20) x100
P (inlet) 0.775
= 74.19%

47
5.4 Comparison of effluent discharge quality with the standards prescribed:
5.4.1 BOD & COD
(Figure 5.5.1: COD & BOD discharge quality characteristics)
5.4.2 Oil and Grease & TSS
(Figure 5.5.2: O&G and TSS discharge quality characteristics)
38.65
72.31
30
250
0
50
100
150
200
250
300
BOD COD
Standard(mg/L)
Parameters
Observed Values (Outlet)
CPCB Standard
1.25
89
10
100
0
20
40
60
80
100
120
O&G TSS
Standard(mg/L)
Parameters
Observed Value (Outlet)
CPCB Standard

48
5.4.3 Ammonical Nitrogen & Phosphate
(Figure 5.5.3: Nitrogen & Phosphate discharge quality characteristics)
5.4.4 Heavy Metals
(Figure 5.5.4: Heavy Metals discharge quality characteristics)
0.264
0.417
0.205
0.003
0.2
4.4
0.1 0.1
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Arsenic Iron Lead Chromium
Standard(mg/L)
Parameters
CPCB Standard
0.127 0.2
50
4.4
0
10
20
30
40
50
60
Ammonical Nitrogen Phosphate
Standard(mg/L)
Parameters
CPCB Standard

49
CHAPTER 6
CONCLUSION
Results from the present study Adequacy and Efficacy of Treatment Plant Treating Electronics
Industry Wastewater has been discussed below-
 BOD removal efficiency of Primary clarifier is 25% which is less than normal observed
efficiency (30%) and for the secondary clarifier it is 32%.
 Treatment plant is efficient in removing heavy metals like Iron and Chromium as the
effluent values are below CPCB standards. But plant is not efficiently removing heavy
metals like Arsenic and Lead (effluent values found above CPCB standards).
 BOD and COD removal efficiency of the treatment plant found to be 75.09% and 72.95%
respectively.
 Treatment plant is capable of removing oil and grease, ammonical nitrogen and
phosphate efficiently.
 Important design parameters of aeration tank MLSS and SVI are found in the acceptable
limit.
 Volume of the Aeration tank required for the suspended growth process is less than the
design volume of the tank.
FUTURE SCOPE AND RECOMMENDATIONS:
In the concerned Effluent treatment plant volume of the aeration tank is not adequate to meet the
suspended growth process; therefore, its capacity should be increased for better efficiency.
Arsenic and lead content is beyond the acceptable limits which should be treated with tertiary
treatment processes. There should also a policy to be formed for better management and
operation of the unit processes.

Electronic Industry Waste Water

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (9)

Similar to Electronic Industry Waste Water

Similar to Electronic Industry Waste Water (20)

Recently uploaded

Recently uploaded (20)

Electronic Industry Waste Water