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1.0 Abstract

Water and wastewater treatment can be divided into three types of treatment

which are physical treatment, chemical treatment as well as biological treatment.

According to the United Nations, physical water treatment can divided into screening,

sedimentation, flotation, granular medium filtration. While for chemical water treatment

it is divided into chemical precipitation, adsorption, disinfection, chlorination, ion

exchange and other chemical applications. The biological treatments are by treating with

activated sludge process, aerated lagoon, trickling filters and biological nutrient removal.

Besides that, the methods such as coagulation-flocculation, electrochemical oxidation and

membrane filtration also can be used in order to treat the unwanted contaminants in

water. In this experiment, the waste water in run unto batch treatment tank as well as

aeration tank and its pH, total dissolved solid (TDS), and conductivity were recorded. In

the batch treatment tank the pH of the waste water were neutralized by using the

coagulant (acid) and caustic soda (basic). On the other hand, in the aeration tank, the

aerator was turned on to add oxygen to water to convert undesirable substances to a more

manageable form (oxidation) as well as to eliminated undesirable gases dissolved in the

water (degasification). Based on the result, it can be seen that the parameters we

measured are compliant with Standard A set by the Department of Environment Malaysia

(DOE).

A distributed control system (DCS) refers to a control system, in which the

controllerelements are not central in location but are distributed throughout the system

with each component sub-system controlled by one or more controllers. The entire

system of controllers is connected by networks for communication and monitoring. Inthis experiment, VMware player is used to simulate the DCS to study single loop PID

level control. In order to achieve that objective, five trial sets of PID tuning parameters is

input to the system and load disturbance is applied to that respective tuning. The process

response of that respective tuning is observed and commented. Based on the result, the

third trial set of PID tuning parameters give the best result where the process value

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remain at the steady state and equally adapt when load disturbance is applied to the

system. For the first and the fifth trial set of PID tuning parameters, the result is equally

the same where the process value did not achieved the steady state even after the load

disturbance is applied. For the second trial, the time interval taken for the process value

to reach steady state is fairly slow and lastly for the fourth trial, the time interval taken for

the process value to reach steady state is very slow. When the load disturbance is applied

to the both trials, the process value reach the steady state is slow pace. In conclusion, the

best PID tuning parameters which are (gain, reset and rate) to control the level in DCS is

5, 30 seconds and 0 second respectively.

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2.0 Introduction

Wastewater is created when water spent or used with dissolved or suspended

solids is discharged from communities, homes, industrial, homes, commercial

establishments, and farms. The water and wastewater need to be treated in order to

remove as much of the suspended solids, organic matter, nutrients, disease-causing

organisms as possible before the remaining water which is also called as effluent is

discharged back to the environment.

According to Sincero et all in their writing, wastewater is divided into two

categories which are sanitary and non-sanitary wastewater or called also as sanitary

sewage. The sanitary wastewaters are wastewaters that have been contaminated with

human wastes. Meanwhile, non-sanitary wastewater is usually waste products from the

industries. The industrial wastewaters are the wastewaters which produced in the process

of manufacturing. In addition to that, the other group is sewage which is the wastewaters

released by the residences, business and also industries in a community. Untreated

wastewater will contains high level of organic material, microorganisms, toxic

compounds as well as numerous pathogens and give the adverse effects to the

environment, humans or animals depending on the types and concentration of waste.

Water and wastewater treatment can be divided into three types of treatment which are

physical treatment, chemical treatment as well as biological treatment. According to

United Nations, the physical water treatment can divided into screening, sedimentation,

flotation, granular medium filtration. While for chemical water treatment it is divided into

chemical precipitation, adsorption, disinfection, dechlorination, ion exchange and other

chemical applications. The biological treatments are treating with activated sludge

process, aerated lagoon, trickling filters and biological nutrient removal. Besides that, the

methods such as coagulation-flocculation, electrochemical oxidation and membrane

filtration also can be used in order to treat the unwanted contaminants in water.Department of Environment Malaysia (DOE) has outlined the discharge limits of

the wastes as indicated below:

Parameters Units Standards

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A B

1. Temperature 0C < 40.00 < 40.00

2. pH pH 6.0 9.0 5.5 9.0

3. BOD5 at 200C mg/L < 20.00 < 50.00

4. COD mg/L < 50.00 < 100.00

5. Suspended Solids mg/L < 50.00 < 1006. Mercury mg/L < 0.005 < 0.05

7. Cadmium mg/L < 0.01 < 0.02

8. Chromium, hexavalent mg/L < 0.05 < 0.05

9. Arsenic mg/L < 0.05 < 0.10

10. Cyanide mg/L < 0.05 < 0.10

11. Lead mg/L < 0.10 < 0.50

12. Chromium, trivalent mg/L < 0.20 < 1.00

13. Copper mg/L < 0.20 < 1.00

14. Manganese mg/L < 0.20 < 1.00

15. Nickel mg/L < 0.20 < 1.00

16. Tin mg/L < 0.20 < 1.0017. Zinc mg/L < 2.00 < 2.00

18. Boron mg/L < 1.00 < 4.00

19. Iron mg/L < 1.00 < 5.00

20. Phenol mg/L < 0.001 < 1.00

21. Chlorine, Free mg/L < 1.00 < 2.00

22. Sulphide mg/L < 0.50 < 0.50

23. Oil & Grease mg/L Not Detectable 10.00

Table 1: Discharge Limit by DOE

In the water river, sewage as well as wastewater, there are several major

parameters that can be identified which are then divided into four parameters. For

instance, physical parameters such color, odor, temperature and turbidity, chemical

parameters that includes biological oxygen demand (BOD), chemical oxygen demand

(COD), total organic carbon (TOC) as well as total oxygen demand (TOD). In addition to

that, pH, acidity and alkalinity are falls into inorganic chemical parameters. Lastly are

bacteriological parameters such viruses, pathogens and others (United Nation, 2003).

In order to produce clear water, the wastewater needs to undergo treatment

process. The treatment process consists of preliminary treatment, primary treatment,

secondary treatment an advanced treatment (Prabu et all, 2011, Mancl). The primary,

secondary and tertiary treatments are the treatments that are carried out before the final

disposal.

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The preliminary treatment is a first step or called also as a screening process

where this process consists of physical unit operations. This treatment is done in order to

protect the pumping and other equipments in the treatment plant. This process is

conducted to screen out, grind out as well as separate and remove the debris. In addition

to that, the preliminary treatment also remove the sticks, rags, large food particles, sand,

rubbish, toys or other large materials, reduces or eliminates the non-favorable wastewater

characteristics such odors, organic loading. Besides that, there are other process belong

the preliminary treatment such equalization, flow equalization and neutralization (Prabu

et all, 2011).

After the screening step, the treatment is proceed with the primary treatment

which are involves the treatment and partial removal of suspended solids, organic matter

and greases from wastewater. This stage is acts as a precursor for the secondary

treatment. The aim of this process is to produce a liquid effluent for downstream

biological treatment and separate the solids as sludge. In this process, the wastewater is

left in a tank for several hours to allow the heavy particles to settle down at the bottom,

meanwhile the greases is float to the top. In order to enhance this primary treatment, the

pre-aeration or mechanical flocculation with chemical additions can be used in this

process.

After that, the clarified wastewater will flow on to the next stage which called as

secondary treatment or biological treatment. This treatment is to remove the soluble and

colloidal organics and suspended solids that escape the primary treatment. Besides that, it

is also to reduce the BOD and COD of wastewater. According to Mancl, in this process,

the bacteria or sewage organisms are cultivated and added in this wastewater, they absorb

the organic matter as their food supply. In order to achieve the secondary treatment, there

are three approaches are used such fixed film, suspended film and also lagoon systems.

Besides knowing as biological treatment, the treatment under trickling filtration, activated

sludge process, oxidation ditch and oxidation ponds are the some procedures belonging to

secondary treatment (Prabu et all, 2011).

Then, the wastewater treatment proceeds to the next treatment which is tertiary or

final treatment. This tertiary treatment is done for purification of wastewater and it

focuses on the removal of significant amounts of nitrogen, phosphorus, heavy metals,

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biodegradable organics, disease-causing organisms such bacteria and viruses. The treated

wastewater can be disinfected by adding chlorine or otherwise by using ultraviolet light

(Marcl). But, as a precaution step, the chlorine cannot be added in high quantities because

high levels of chlorine may be harmful to aquatic life and others. Besides that, the

treatment systems also often add a chlorine-neutralizing chemical to treat the wastewater

before it is discharged.

In conjunction with the water treatment, Marcl has stated that there are also

advanced treatment such coagulation process. The coagulation is needed in some

treatment in order to remove nutrients from the wastewater. Besides that, according to

Subramanian, there are several other methods to remove suspended solids (micro

staining, coagulation, filtration and flocculation), removal of dissolved solids (ion

exchange, reverse osmosis, electrodiallysis), removal of dissolved organic compounds

(adsorption, sludge treatment and disposal and disinfection). There is also other method

such membrane bioreactor (MBR) (Radjenovi et all, 2008)

Figure 1 below exhibit the typical process flow of wastewater treatment

. Figure 1: Typical Wastewater Treatment

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3.0 LITERATURE REVIEW

3.1 Wastewater

Wastewater is any water that has been adversely affected in quality by

anthropogenic influence. It comprises liquid waste discharged by domestic residences,

commercial properties, industry, and/or agriculture and can encompass a wide range of

potential contaminants and concentrations. In the most common usage, it refers to the

municipal wastewater that contains a broad spectrum of contaminants resulting from the

mixing of wastewaters from different sources. The objective doing waste water treatment

is to make sure that all human and industrial waste can be disposed without cause a

danger human health and damage natural environment. To remove solids, organic matter

and nutrients from wastewater, combination of physical, chemical and biological

treatment is need. In order to describe different step in wastewater treatment the term that

be used is preliminary, primary secondary, and tertiary or advanced wastewater

treatment. A generalized wastewater treatment is shown in Figure 2.

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Figure 2 Process in wastewater process

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3.2 Biological treatment

Biological treatment methods is the most effective and eco-friendly than any other

available treatment process cause them to dominate the secondary wastewater treatment

sector. The demand for biological wastewater treatment equipment is on growth path

which is catalysed by the need to meet obligatory wastewater treatment standards,

imposed by environmental legislation to municipalities and industries in the vast part of

developed countries.

The main advantages of biological wastewater treatment are as follows:

Low capital and operating costs compared to alternatives such as chemical-oxidation

processes

True destruction of organics, versus mere phase separation, such as with air stripping

or carbon adsorption

Oxidation of a wide variety of organic compounds

Removal of reduced inorganic compounds, such as sulphides and ammonia, and total

nitrogen removal possible through de-nitrification

Operational flexibility to handle a wide range of flows and wastewater characteristics

Reduction of aquatic toxicity

The purpose of biological treatment of wastewater is to reduce BOD content in the

water by using the bacteria which feed on the organic materials in the wastewater. The

principle in the biological process is the bacteria will eat all the organic material present

in the wastewater and using their metabolism it will change organic material into cellular

mass. This cellular is no longer in the solution but will be precipitated at the bottom of

settling tank. The water exiting the tank is much clearer before it entered the tank. Supply

of oxygen also needed in this process because cells or bacteria not only need organic

material as food but also oxygen to breathe just like human. Without the oxygen the

biological degradation of the waste is slowed down thereby requiring a longer residency

time of water in the system.

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4.0 OBJECTIVE

The main aim of this experiment is to treat the municipal or industrial wastewater influent

by using chemical and biological treatment. This treatment is used in order to produce

clean water before it is discharge because wastewater has a lot of contaminants that will

cause the adverse effects to environment. The chemical treatment process is done by

adding the chemical compound such coagulant, caustic soda and flocculants. Meanwhile,

the biological treatment is the treatment by using bacteria which the bacteria will absorb

the organic matter as the food supply.

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5.0 METHODOLOGY

5.1 Treatment of Water and Wastewater Using Chemical & Biological Process

At the plant, the bulky box tank is filled with raw water samples. Valves (V1, V2

& V4) were opened while valves V3 & VA were closed to fill wastewater at batch

treatment tank. The portable transfer pump, P1 was started to fill the tank at 250 L

marked on the tank. The pump was stopped and the mechanical agitator, M1 was started.

The speed of the agitator was controlled using the interval located inside the Aquatrend

Panel. The pH of the wastewater solution was checked by using conductivity meter. If the

solution in basic condition, the coagulant is added until achieved 8.5 meanwhile if the

solution in acid condition, the is added caustic soda until pH achieved 7. The value of the

waste water pH, total dissolved solid and the conductivity in the batch treatment tank

were recorded according to Table 4.1. The valves (VB & VC) were opened while valve

VA was closed. Batch treatment transfer pump, TP1 was started. The transfer pump will

stop automatically when the water level in batch treatment tank is low, which is detected

by a level sensor. Valve VE was opened on the Aeration Tank to blow the wastewater byusing compressed air. The value of the waste water pH, total dissolved solid and the

conductivity in the aeration tank were recorded according to Table 4.2. Overall, this

process can be described in Figure 3.1.

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Figure 3.1: Single capacity tank pressure PID control

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6.0 Result and Discussion

6.1 Results:

Parameter Value

pH 85

TDS 850 mg\L

Conductivity 1363 S\cm

Table 1: Batch Treatment Tank (BTT)

Parameter Value

pH 10.61

TDS 1324 mg\L

Conductivity 834 S\cm

Table 2: Aeration Tank (AT)

6.2 Discussion:

Sewage is the wastewater released by residences, businesses and industries in a

community. It is 99.94 percent water, with only 0.06 percent of the wastewater

containing dissolved and suspended solid material. The cloudiness of sewage is caused

by suspended particles.

In our experiment, we conducted treatment for the water using chemical and biological

processes. In this process, we controlled the pH of the waste water till it reached a pHbetween 7 and 8 which is the suitable range for drinking. We kept treating the waste

water till it matched the standards for the drinking water which is set up by the

Department of Environment Malaysia (DOE).

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This treatment is in two steps. First at the Batch Treatment Tank (BTT), chemicals

compounds such as caustic soda, coagulant and flocculants are used to treat the water,

where they separate suspended solids and greases from wastewater and also reduce

and/or increase the pH level. Waste-water is held in a quiet tank for several minutes. The

solids drawn off the bottom and skimmed off the top receive further treatment as sludge.

The clarified wastewater flows on to the next stage of wastewater treatment. Clarifiers

and septic tanks are usually used to provide in this step. Before transfer the water to the

next tank, we measured the parameters of the waste water. As we see from Table 1, the

pH value of the waste water matches the standard which has been set up by DOE in

standard A.

Then, we transferred the waste water to the Aeration Tank (AT). We couldnt get the

final result of this treatment due do the time constraint of our experiment. But referring to

our literature review, this step of treatment is a biological treatment process to remove

dissolved organic matter from wastewater. Sewage microorganisms are cultivated and

added to the wastewater. The microorganisms absorb organic matter from sewage as their

food supply. Three approaches are used to accomplish secondary treatment; fixed film,

suspended film and lagoon systems.

According to the theory, after finishing the above steps, we come to the final step. Final

treatment focuses on removal of disease-causing organisms from wastewater. Treated

wastewater can be disinfected by adding chlorine or by using ultraviolet light. High levels

of chlorine may be harmful to aquatic life in receiving streams. Treatment systems often

add a chlorine-neutralizing chemical to the treated wastewater before stream discharge.

There was no data available from the PC as the sensors in the automated system were not

functioning. Hence no BOD or COD values were taken. The other parameters were

measured by using other available instruments.

As we observed our data, table 1 and 2, we can see that our experiment ran correctly

because it matches with the standard set of data given by the DOE.

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Questions:

1. What is the purpose of adding caustic soda into the Batch Treatment Tank in the

Chemical & Biological Treatment Unit?

Caustic soda is sodium hydroxide and is used to lower the alkalinity of the

waste water. The common factors for selecting caustic soda are its stronger

basicity and easier storage and handling.

2. What is the name of processes occurred in the Batch Treatment Tank after adding

caustic soda, alum & polymer?

The process is flocculation

3. What is the purpose of aeration inside the Aeration Tank?

In industrial water conditioning, one of the major objectives of aeration is to

remove carbon dioxide. Aeration is also used to oxidize soluble iron and

manganese (found in many well waters) to insoluble precipitates. Aeration is

often used to reduce the carbon dioxide liberated by a treatment process. For

example, acid may be fed to the effluent of sodium zeolite softeners for boiler

alkalinity control. Carbon dioxide is produced as a result of the acid

treatment, and aeration is employed to rid the water of this corrosive gas.

Similarly, when the effluents of hydrogen and sodium zeolite units are

blended, the carbon dioxide formed is removed by aeration. Others purposes

are for the removal of volatile organic substances, hydrogen sulfide,

ammonia, and volatile organic compounds.

4. Why level sensors are used on the system?

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Level sensors detect the level of substances that flow, including liquids,

slurries, granular materials, and powders.Water treatment applications

place high demands on pressure and level measuring instruments.

5. What is the function of diammonium phosphate in Chemical & Biological

Treatment Unit?

Diammonium phosphate is a water-soluble salt. It enhances the growth of

the bacteria which is used in the water treatment.

6. Compare your results with EQA Standard?

The pH values obtained in our experiment comply with EQA Standard A.

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7.0 Conclusion and Recommendation

7.1 Conclusion

In this experiment, the objective was to treat the waste water using chemical & biological

process. Due to the time constraint, we could only treat the water using the chemical

process. In this part of experiment, we achieved our objectives and could manage to reach

the Standard A as given by the DOE.

In the other hand, we couldnt treat the waste water using a biological process due to

equipment problems and a lack of time. But we could get the clear idea of that process

form the articles which we referred to for this experiment.

From this experiment, we learned that waste water must be treated before being released

back to the environment for industrial or residential usage to remove the suspended solids

and other microorganisms which may have harmful effects to consumers. The kind of

treatment utilized in this experiment is suitable to treat the waste water as the chemical

and biological process helps to remove the suspended solids and microorganisms in the

water.

7.2 Recommendation

The first recommendation is for a longer time period to conduct the experiment as the

bacterias used need a few days to reach optimum growth levels.

The second is to ensure that all the equipments and tanks in the water treatment plant are

maintained well in order to ensure that accurate readings can be taken during the

experiment.

The equipments used in measuring the parameters must also be properly calibrated to

ensure that accurate results are obtained.

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8.0 References

1. Sincero, A. P., & Sincero, G. A. (2003). Physical-chemical treatment of water and

wastewater. IWA Publishing.

2. United Nation Economics and Social Commission for Western Asia (2003).

Waste-water treatment technologies : A general review. Available online at

3. http://www.igemportal.org/Resim/Wastewater%20Treatment%20Technologies

%20A%20general%20review.pdf

4. Prabu, S. L., Suriyaprakash, T. N. K., & Kumar, J. A. (2011). Wastewater

treatment technologies: A review.Pharma Times, 43(5), 1-5

5. Mancl, K. Wastewater treatment principles and regulations. Available online at

http://ohioline.osu.edu/aex-fact/0768.html

6. Subramanian, M. S. Advanced Waste Water Treatment. Module 1.5.

environmental Chemistry and Analysis. Available online at

7. http://nptel.iitm.ac.in/courses/IITMADRAS/Enivironmental_Chemistry_Analysis/

Pdfs/1_5.pdf

8. http://engineering.dartmouth.edu/~cushman/courses/engs37/biotreatmenttypes.pdf

9. http://water.me.vccs.edu/courses/ENV149/methods.htm

10.http://www.fao.org/docrep/t0551e/t0551e05.htm#3.2.1%20preliminary

%20treatment

11.Radjenovi, J., Matoi, M., Mihatovi, I., Petrovi, M., & Barcel, D. (2008).

Membrane reactor (MBR) as an advanced wastewater treatment technology. Hdb

Env Chem, 5(S/2), 37-101.

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