SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN

BACHELOR OF QUANTITY SURVEYING (HONOURS)

BUILDING SERVICES 1 (BLD60403)

SUSTAINABLE WASTEWATER TREATMENT

GROUP MEMBERS:

NAME STUDENT ID1. ADAM WONG 0322520

2. CHLOE SIM TIING ERN 03229323. KOK KA SHING 0323553

4. PUI CHUN SHIAN 03234705. YEONG POH LING 0323590

6. ZACHARY OOI CHENG EN 0323120

LECUTURER: LIM TZE SHWA

Table of Content

TITLE PAGE1. Introduction 3-8

2. Installation Process 9-163. Management system 17-23

4. Advantages and Disadvantages 24-255. Case Study: Finding and Explanation 26-36

6. Possible Problems to the System 37-387. Recommendation for Future Improvement 39-42

8. Learning Outcomes 439. References 44

Introduction

Sustainable Wastewater Treatment

According to the USGS Water Science School, it is said that about 71% of the Earth’s

surface is covered by water. However, the ocean holds 97% of the Earth’s water and the

remaining 3% is freshwater found in different forms. 2% of the water is in the form of frozen

fresh water which is not usable and only 1% is in the form of freshwater. It may seem like water

is abundant but the fact that only 1% is suitable for consumption, it requires us to reuse and

recycle water by having a sustainable wastewater treatment to protect our constant freshwater

supply.

The main objective of a wastewater treatment is to produce clean water of high quality

effluent, which can be safely distributed to the environment and to be reused. A wastewater

treatment plant is used to separate the solid wastes and water by three different treatment

processes namely primary, secondary and tertiary. Sewage treatment methods are classified

into 3 different operations which include the physical, chemical and biological processes. Each

of them has different applications and methods of cleaning the water from pollutants.

A sustainable wastewater treatment can be defined as a sewage system that are

effective, simple to operate and low cost in terms of the technologies. It has to be

environmentally-friendly as well so that they consume less energy and therefore have positive

impacts on the environment. Also, a sustainable treatment uses biological processes that will

not cause environmental nuisance. For example, they produce lower amounts of excess sludge

and the smell problems can be controlled easily and more effectively.

The objectives of a sustainable wastewater treatment aims to protect the health of

humans and the environment. It does not adversely impact the health of humans and other

species. Besides that, a sustainable treatment must be able to preserve and protect the

environmental quality of ecological systems by making sure it does not produce any means of

pollution that will harm the environment and human. Sustainable also means that the

wastewater treatment need to have the ability to recover energy and nutrients present in waste.

Last but not least, a sustainable wastewater treatment needs to be able to utilize the resources

efficiently especially the resources that are running out and are non-renewable.

Wastewater Treatment Methods

Wastewater treatment can be organized and categorized into 3 different treatment

methods. The treatment methods are physical unit operations, chemical and biological unit

processes. Physical unit operations are known as treatment methods that use the application of

physical forces to treat sewage. There is no changes in chemical or biological as only physical

phenomena are present to treat the wastewater. Physical operations include screening, mixing,

flocculation, sedimentation, filtration and flotation.

On the other hand, chemical treatment involves using chemical reactions to improve the

water quality, in which the removal or conversion of pollutants are done by the addition of

chemicals. Chemical unit processes include precipitation, adsorption, disinfection and

chlorination. The most commonly used chemical process is probably chlorination.

Lastly, biological treatment is a method which removes pollutants by biological activity.

Microorganisms such as bacteria is used in the biochemical decomposition of wastewater to

stable end products. In general, biological treatment methods can be divided into aerobic and

anaerobic methods, based on availability of dissolved oxygen. Biodegradable organic

substances are converted into gases that escape to the atmosphere and cell tissue is removed

by settling.

Wastewater Treatment Processes

The wastewater undergoes several stages in its treatment process which can be

classified into 3 different stages.

The first stage of wastewater treatment process is called the primary treatment. This

stage mainly involves removing solids and some organic materials. Most of the solids are

removed or separated from wastewater by a physical process called sedimentation. The organic

solids sink to the bottom and form a sludge and fats rise to the surface to form a scum. The

purpose of primary treatment is to reduce the velocity of wastewater sufficiently to permit solids

to settle and floatable material to surface.

Moving onto the second stage, also known as Secondary stage, biological treatment is

used to remove organic and suspended solid waste. This treatment uses biological activity to

catch the dissolved organic matter missed in primary treatment. Activated sludge will consume

Primary

Secondary

Tertiary

the organic matter as food, converting it to carbon dioxide and other energy. The main purpose

of secondary treatment is to reduce BOD (Biochemical Oxygen Demand). The wastewater is

cleaned by the microorganisms called “activated sludge” through digesting organic materials

and other contaminants. Secondary treatment includes biological treatment to remove organic

and suspended solids.

The last stage is the tertiary treatment whereby water is thoroughly cleaned by using

more advance treatment systems. Chemicals such as disinfection are poured into to treat the

waste water to reduce nitrogen and phosphates. Nitrogen and phosphates act as fertilizers and

can cause serious problems when they are being streamed into lakes or rivers. It will cause

algae blooms which results in eutrophication. In this tertiary treatment, bacteria is used to

denitrify nitrates present in water producing nitrogen gas which is then released into the

atmosphere. Unlike secondary treatment, tertiary treatment includes both biological and

chemical treatments to remove nutrients and pathogens.

Types of Wastewater Treatment

In Malaysia, there are mainly 2 types of wastewater treatment systems. The premises’

wastewater systems are either connected to a public sewage treatment plant or have an

individual septic tank. The most commonly used type of sewerage system in Malaysia is the

Individual Septic Tank (IST).

Individual Septic Tank (IST)

Individual Septic Tank (IST) is more commonly used in Malaysia. A proper set-up of IST

is usually located outside the premises compound either at the side, rear of front. A septic tank

is a multi-chamber storage tank that separates the liquid between the solid waste. The liquid is

allowed to flow out of the tank and be disposed off separately. Only a part of the sewage that

flows into it can be treated inside the septic tank and it needs to be serviced over time to ensure

that it works efficiently. A septic tank can only partially treat sewage and the treated sewage is

usually of low quality and has bad smell. They usually do not full treat sewage as the maximum

amount of sludge that a septic tank can store is approximately one third of its total volume.

Individual septic tank works by allowing raw sewage to flow into the tank whereby the

solid waste or sludge settles at the bottom of the tank and the oil or grease from the sewage

floats to the top, forming a layer of scum. Scum acts as an exhibitor to prevent oxygen from

dissolving and it will result in anaerobic digestion taking place. Raw sewage has to be retained

for at least 24 hours for anaerobic digestion to completely breakdown the solid matter.

Connected Sewage System

A connected sewerage system allows its customers to have sewage outlets that

are directly linked to a sewage treatment plant via an underground network of sewer pipes. A

sewage treatment plant is a combined plant that converts raw sewage into effluent and solid

waste. There are different shapes and sizes for these treatment plants but they serve the same

function which is treating the waste by combining oxygen and organic waste to speed up a

natural biological breakdown.

Connected sewerage systems comprise a network of underground sewer pipes,

pump stations, sewage treatment plants and sludge treatment facilities. They generally operate

by gravity. As a result, sewage treatment plants are usually located at drainage catchment

outlets so that all the sewage can be captured easily without spending a large amount of money

on pumping.

Installation Process

First of all, a survey has to be conducted by the authorities and the Government to have

a fair estimation on the number of population before installing the treatment plant. The

wastewater treatment plant will operate 24 hours continuously once it started operating and it is

measured by m3 per day. The population estimation is very crucial because it can prevent

overflow of the treatment plant due to unable to support the wastewater discharge by the

people. Wastewater flushing from the toilets, bathing, washing sinks and general cleaning goes

down the drain and into a pipe, which joins a larger sewer pipe under the road. The larger pipe

also joins a major pipe that leads to the treatment center.

What is a Water Treatment Plant Operator?

A water treatment plant operator works in water treatment plants. Water is pumped from wells,

rivers, streams, and reservoirs to water treatment plants, where it is treated and distributed to

customers. A water treatment plant operator runs the equipment, control the processes, and

monitor the plants that treat the water.

What does a Water Treatment Plant Operator do?

Water treatment plant operators typically do the following :

Add chemicals such as ammonia, chlorine or lime, to clear water

Inspect equipment on a regular basis

Monitor operating conditions, meters, and gauges

Collect and test water and sewage samples

Record meter and gauge readings

Operate equipment to purify and clarify water

To process or dispose of sewage

Clean and maintain equipment, tanks, filter beds, and other work areas

Stay current on environmental laws and regulations

To ensure safety standards

Other than that, it takes a lot of work to get water from natural sources (reservoirs, streams,

and groundwater) into our taps. Similarly, it is a complicated process to convert the wastewater

in our drains and sewers into a form that is safe to release into the environment. Moreover, the

specific duties of water treatment plant operators depend on the type and size of the plant. In a

small plant, one operator may be responsible for maintaining all of the systems. In the large

plants, multiple operators work the same shifts and are more specialized in their duties, often

relying on computerized systems to help them monitor plant processes.

Wastewater Treatment Process

STAGE 1: SCREENING

First, screening is the first stage of the wastewater treatment process. Screening removes large

objects for example like diapers, nappies, sanitary items, cotton buds, face wipes and even

broken bottles, bottle tops, plastics and rags that may block or damage equipment. Moreover,

the special equipment is also used to remove grit that gets washed into the sewer.

STAGE 2: PRIMARY TREATMENT

This involves the separation of organic solid matter or human waste from the wastewater. This

is done by putting the wastewater into large settlement tanks for the solids to sink to the bottom

of the tank. The settled solids are called ‘sludge’. At the bottom of these circular tanks, large

scrapers continuously scrape the floor of the tank and push the sludge towards the center

where it is pumped away for further treatment. Furthermore, the rest of the water is then moved

to the Secondary treatment.

STAGE 3: SECONDARY TREATMENT

At this stage, the water is then put into a large rectangular tanks and these are called aeration

lanes. Next, air is pumped into the water to encourage bacteria to break down the tiny bits of

sludge that escaped the sludge scraping process.

STAGE 4: FINAL TREATMENT

After that, the treated wastewater is then passed through a settlement tank. Here, more sludge

is formed at the bottom of the tank from the settling of the bacterial action. The sludge is

scraped and collected for treatment again. The water at this stage is almost free from harmful

substances and chemicals and is allowed to flow over a wall where it is filtered through a bed of

sand to remove any additional particles.

Primary (mechanical) treatment is intended to expel gross, suspended and skimming solids

from crude sewage. It consists screening to trap strong items and sedimentation by gravity to

expel suspended solids. "Mechanical treatment" level is now and then alluded, chemicals are

mostly applied to quicken the sedimentation process. Primary treatment can slow down the

process of BOD of the approaching wastewater by 20-30% and the aggregate suspended solids

by some 50-60%. Primary treatment is generally the principal phase of wastewater treatment.

Numerous propelled wastewater treatment plants in industrialized nations have begun with the

primary treatment, and have then included other treatment stages as wastewater burden has

developed, as the requirement for treatment has expanded, and as assets have gotten to be

accessible. Moreover, Sludge also removed from the bottom and the water from top enters

secondary treatment.

Secondary (biological) treatment expels the broke down organic matter that departures from

primary treatment. This is accomplished by microorganisms devouring the organic matter as

nourishment, and changing over it to carbon dioxide, water, and vitality for their own particular

development and generation. The organic process is then trailed by extra settling tanks to expel

a greater amount of the suspended solids. Around 85% of the suspended solids and BOD can

be expelled by a well running plant with secondary treatment. Then, Secondary treatment

advances consists the secondary initiated sludge process, the variations of lake and built

wetland frameworks, streaming channels and different types of treatment which use biological

activity to separate organic matter.

Tertiary treatment can expel more than 99 percent of the considerable number of pollutants

from sewage, creating an emanating of just about drinking-water quality. The related innovation

can be exceptionally costly, requiring an abnormal state of specialized expertise and all around

prepared treatment plant administrators, a relentless vitality supply, and chemicals and

particular hardware which may not be promptly accessible. A case of a run of the mill tertiary

treatment procedure is the adjustment of an ordinary secondary treatment plant to expel extra

phosphorus and nitrogen.

Sludge treatment is the strong waste that are isolated from the liquid waste through

wastewater treatment. Through sewage treatment process, whether from the begin of the

process until the end of the process, can create huge measures of sludge that require further

treatment and put to alternative use. Untreated sludge is a significant environmental and

general health risk. Along these lines, sludge must be controlled before being arranged off in an

environmentally safe way.

Here are the functions:

1) Sump and pump house:-wastewater is used to collect in the sump and pump to a

higher tank treatment.

2) Approach Channel- allow the sewage to flow by gravity to the succeeding units of the

treatment plants.

3) Bar screen- catches large objects that have gotten into sewer system such as

bricks , bottles , pieces of woods.

4) Grit Chamber- to remove remaining solid materials.

5) Skin chamber- to remove oil from wastewater.

Sludge Treatment

A sludge treatment is a process that manages and disposes off sewage sludge. Sludge

production from wastewater treatment process is high and the disposal of excess sludge will be

forbidden in a near future, thus increased attention has been turned to look into potential

technology for sludge reduction. A study has been attempted to review alternative sludge

disposal methods, including anaerobic digestion, aerobic digestion and landfills. In these sludge

processes, up to 100% of excess sludge can be reduced without significant effect on process

efficiency and stability. Other than that, sludge contains essential nutrients which are

phosphorus and nitrogen. These nutrients are potential benefits for plants as fertilizers. Last but

not least, the organic carbon in the sludge also desirable as a soil conditioner because it

provides improved soil structure for the plant roots.

Introduction of Wastewater Management System

Wastewater treatment is a process used to convert wastewater which is water no longer

needed or suitable for its most recent use. Water are used for many purpose in our daily life

which is not limited for drinking water only and it is being used by homes, business, factories,

hospitality and many more. The extent of damage depend upon type pf pollutant present in

effluent. Non bio-degradable pollutant like mercury are most deadly as they accumulate in

aquatic organism which lead to Bio magnifications.

Large quantity of biodegradable waste can affect living organism in the water bodies in

which waste are discharged area is necessary to treat effluent or waste water before

discharging in water body. This lead to high demand of water due to the growth of human

population and economic development. Therefore, the groundwater is being over-exploited in

order to satisfy the demand. So, a sustainable wastewater management is required to manage

the contaminants in the wastewater.

Reuse and Recycling of Wastewater

Water can be recycled as well. Water recycling is reusing treated wastewater for

beneficial purposes such as agricultural and landscape irrigation, industrial processes, toilet

flushing, and replenishing a ground water basin. Water recycling offers resource and financial

savings. The water due to the high demand of the groundwater, water recycling is the best

solution to overcome this problem as it helps to secure and reduce the excessive amount of

groundwater used by the region. Wastewater treatment can be tailored to meet the water quality

requirements of a planned reuse.

Recycled water for landscape irrigation requires less treatment than recycled water for

drinking water. No documented cases of human health problems due to contact with recycled

water that has been treated to standards, criteria, and regulations have been reported. Recycled

water can satisfy most water demands, as long as it is adequately treated to ensure water

quality appropriate for the use. In uses where there is a greater chance of human exposure to

the water, more treatment is required. As for any water source that is not properly treated,

health problems could arise from drinking or being exposed to recycled water if it contains

disease-causing organisms or other contaminants. The water then can be reused over and over

again for various purpose such as for drinking water or agriculture as this sector consumes a

large percentage of water.

Reuse water quality

The quality of reused water depends on the treatment system, the water’s previous use and the

chemicals used in the home. A number of things can simplify treatment requirements.

Collection of Wastewater

Waste water collection systems gather the used water from our homes, businesses and

industries and convey it to a wastewater treatment plant. It known as a storm water collection

system conveys water resulting from runoff of rain and snow from buildings and paved and

unpaved areas to a natural watercourse or body of water, usually without treatment. Waste

water collection and treatment systems vary from community to community depending on the

population size and local needs. Such systems may separate the storm and sanitary flows, or

have a combined sewer system, or both. Wastewater collection and treatment systems are

responsible for collecting and treating residential, commercial and industrial wastewater. There

are two ways can be used to collect wastewater which are through centralized systems or

decentralized systems.

1. Centralized Systems

public sewer systems

serve established towns and cities

provide treatment and disposal services for neighboring sewer districts

large-scale system

gather wastewater from many users for treatment at one or few sites

economical, allow for greater control, require fewer people

produce only one discharge to monitor instead of several.

2.

Decentralized Systems

Many of decentralized system failure cases happened because lack of improper maintenance.

This problem can be overcome by providing the person in charge of maintaining the system with

enough skills and practices to ensure the system are well- managed.

do not connect to a public sewer system

may be treated on site (most common) or discharged to a private treatment plant

require well trained staffs and high cost of maintenance

Awareness of Wastewater

Pollution prevention is not producing waste in the first place. It means doing what we can

to reduce the amount and toxicity of waste we generate. Reducing, reusing or recycling wastes

helps minimize the need to treat and dispose of it. Pollution prevention can be as simple as

encouraging water conservation, or as complex as designing an operation to use treated

wastewater as a substitute for traditional sources of water. The World Bank Group hold onto the

principle that water is everyone’s business. This means that everyone in this world has their

own portion and responsible in managing the water and wastewater sources. First and

foremost, in order to lessen the amount of wastewater that we need to deal with currently, the

responsible authorities should take part by enforcing the laws and policies regarding wastewater

consumed by citizens. Apart from that, citizens also play a big role in consuming the

wastewater. Hence, every person in community regarding their ages should be educated with

awareness campaign to encourage them in the reduction of the excessive amount of

wastewater production. This in return will makes them better in managing the wastewater.

Treatment of wastewater

The principal objective of wastewater treatment is generally to allow human and

industrial effluents to be disposed of without danger to human health or unacceptable damage

to the natural environment. Irrigation with wastewater is both disposal and utilization and indeed

is an effective form of wastewater disposal as in slow-rate land treatment. The main objective of

wastewater treatment is to reduce the level of pollutants in the wastewater before it is being

discharged into the environment without causing harm to the human health or to the natural

environment. The wastewater can be naturally treated by the sun, vegetation, soils and

microorganisms if the volumes of wastewater discharged into the environment is very small.

However due to the growth of the human population, millions gallon of wastewater are produced

makes it impossible for the nature to deal with it. So, an appropriate and relevant technology is

needed to treat wastewater before discharging it into the environment. Wastewater includes

substances such as human waste, oils, chemicals and many more that is contributed by homes,

business and factories.

Storm water also a part of wastewater although many thinks that it is clean. Urban storm

water flowing over lawns, rooftops, and paved surfaces are polluted by lawn chemicals, oil and

gasoline spills on streets, plus other substances that become entrained in them as they make

their way to a stream, river, or lake. These flows must also be subjected to some form of

treatment to make them less harmful to the environment. Restoration of water quality is

accomplished through the use of a variety of pollution control methods. Harmful substances

such as chemicals that contains on the street can contaminate the rainwater that runs down it

and may harm the quality and ecosystem in the rivers or lakes. Improper treated wastewater

has a significant impact towards human health and ecosystem.

Advantages & Disadvantages of Wastewater Treatment

Advantages

Wastewater could be any liquid waste which may contain animal, vegetable or chemical

waste in solution form. Wastewater treatment processes are needed to remove a variety of

contaminants that may or may not be harmful to make it usable again.

The benefits of wastewater treatment may vary depending on the nature of the

contaminants in the water and the end use of the water treated. First of all, every living thing on

Earth needs water to live and that is why we need clean water. However, only about 3% of the

Earth’s water is safe to drink. Water is a renewable resource as it can be purified, treated or

filtered in many different ways and treatments. One of the advantages of wastewater treatment

is to provide clean water that is potable and to maintain clean water for reuse. Besides that,

wastewater may contain disease-causing microorganisms that need to be filtered. Through

wastewater treatment processes, there is a filtering system that will block these potential

disease-causing microorganisms to be blocked and also a further treatment that destroys

harmful organisms. This treatment helps in purifying the water and prevents potential disease

and bacteria that will harm the health of people from entering other water sources.

Actually, wastewater treatment also helps in the economic side for the country. Many job

opportunities are made available from wastewater treatment research and processing. For

instance, people are needed to maintain these facilities and also for treatment researches. Also,

clean water environment attracts tourists from all around the world and it encourages tourism

too.

Wastewater treatment processes are ever-changing as researches strive to develop new

treatment techniques. Development of new processes allow these wastewater treatments to

save more time, energy and resources. This makes it an advantage so that these resources will

be made available for other needs.

Disadvantage

Reusing wastewater is not riskless as it can have negative impacts too. Although there are

advantages of having wastewater treatment as mentioned previously, it may have negative

effect on human and the environment around.

One of the main reasons why the wastewater treatment is a hassle and is a disadvantage is

the cost and financing of it. Using wastewater treatments to process used water also means

increased costs for infrastructure which includes facilities, pipes, tanks and the water treatment

plant itself. Maintenance fee is also high as continuous operations and maintenance are needed

to ensure the treatment is working fine to supply enough clean water. Different infrastructures

are needed to separate the fresh water from flushed water in a building which require higher

costs. The Malaysian government has to spend large sum of money each year on wastewater

treatment to supply clean water to the country.

In addition, the wastewater treatment has also triggered a few health concerns among the

public. Water that undergoes thorough treatment for drinking purposes is safe but somehow not

treated to a high enough standard to make it safe for drinking. There might still be pathogens

present in the water but they might not necessary be the ones that will make you sick. We might

not know if the drinking water could affect health risks in spite of the bacteria contained in the

water. In some cases, certain nutrients, organics and heavy metals in wastewater are

contaminants that will bring harm to the human’s health if not treated in a proper way. There are

also unknown impacts that wastewater treatment will bring to the surrounding ecosystem.

Case Study 1: Malaysia

Malaysia is the home to a total of 30 million people and its population is still rapidly

expanding. Malaysia’s entire population has access to improve water source and 96% had

access to improved sanitation in 2008 according to the United Nation’s Joint Monitoring

Program for Water Supply and Sanitation. Malaysia’s water availability depends on the weather

and what are the current water levels in the dams across the west peninsular. If it’s the rainy

season the water levels in the dams would be high and it would be adequate for most of the

residences living in the peninsular. But it is during the dry season where most Malaysians would

be subjected to water rationing or a complete cut off of their water supply as there is not enough

water in the dams to be supplied to everyone at once.

1. Water catchment areas

A water catchment area Ulu Langat Park – An important water catchment area for states

such as Selangor and Kuala Lumpur

A water catchment area is defined as an area which surface runoff water is collected which

is carried by a drainage system like a river and its tributaries. Most of the area of land where the

surface water from rain or other water sources converges to a single point and it is usually the

exit of the catchment basin. This is where the water joins another waterbody such as a lake,

wetlands, reservoir and etc. In closed drainage basins the water converges to a single point

inside of the basin known as a sink which may be a permanent lake. The drainage basin also

includes both rivers and streams that convey water to is as well as the land surfaces which

water drain into those places and is separated from adjacent basins by a drainage divide.

Malaysia receives most of it’s water from rivers but water catchment areas are also

important to us as that is also where most of our water that we use in our household comes

from a water catchment area. Malaysia has a total of 189 river basins and 89 of them are found

in the West peninsular, 78 of them are in Sabah and 22 are in Sarawak. The main water

catchment area which is one of the most important water catchment areas for the entire west

Malaysia is “Banjaran Titiwangsa”.

2. Dams

Another source of water for Malaysians are dams and they are as important as water

catchment areas. There are a total of 34 dams in the entire Malaysia that its function is to supply

water. Important dams like the Sg. Selangor dam, Batu and Klang Gates dam and the Langat

and Semenyih dams provide an estimate of 98% of all the water supply to major cities in the

west peninsular which includes Kuala Lumpur, Selangor and Putrajaya.

But these dams are not perfect also. The dams can only store so much water for a short

period of time that if the dry season hits Malaysia which is quite often and this causes a major

problem to the dam as they rely on the rain or the water catchment areas to fill up the dams to

supply water to people. So during the dry season most of the dams would run out of water

which in turn causes a water shortage and force most of the household to be subjected to water

rationing. This is probably the only fatal flaw of using a dam to supply water other than all the

damage to surrounding ecosystem.

How a dam works Klang Gate Water Dam

3. Indah Water Konsortium

The Malaysian wastewater company “Indah Water Konsortium Sdn Bhd” is a wholly owned

government company and it is tasked with processing all the raw sewerage from every

household in the entire west Malaysia but excluding the state of Kelantan and Johor. The

company was founded in the year 1994 which makes it a relatively new company and its

headquarters is based in Kuala Lumpur. The current CEO of the company is Mr. Abdul Kadir

Mohd Din.

Indah Water’s logo

The company also has a green initiative program called “Biosolids”. The purpose of this

program is to reuse the solid waste from the sewerage treatment process and turn it into a

fertilizer and soil conditioner that contains much organic nutrients.

Process for making Biosolids

Not only that but the company also have another program which they use wastewater as

another water source after filtration and the program is called “Bioeffuent”. This program uses

filtered wastewater to be supplied to a few sectors which is the urban, agriculture, industrial and

enviroment. The process uses previous technology like reverse osmosis, sand filtering, ultra

filtration and micro filtration to turn wastewater into clean water and supply it to the few sectors

mentioned above.

Bioeffluent treatment process

Case study 2: Singapore

Water shortage is a growing problem in resource-scarce Singapore. Increased water

demand due to population growth, environmental needs, climate change and water resource

contamination are obstacles in finding sustainable water resources. Therefore, new legislation is

required, especially in promoting reuse of wastewater. Singapore is a Southeast Asian island

country, with an estimated population of 5.5 million living on less than 750 square kilometers of

The benefits of the Bioeffluent reuse program

are:

- Efficient pollution control

- Allows for a more sustaniable water

resource

- Reduce pressure on natural water

resources

land. Singapore is known for its robust economy but is insufficient in one of the world’s most

important daily resources, water.

Water has always been Singapore’s first national priority. Lee Kuan Yew, Singapore’s

first prime minister, pushed to develop a self-sufficient water supply of Singapore in response to

the shortage of water in the 1960s and ‘70s. Over the last 50 years, Singapore has built a robust

and diversified supply of water known as the “Four National Taps”.

1. Water from Local Catchment

This represents one of the pillars of Singapore’s sustainable water supply. Since 2011, the

water catchment area has been increased from half to two-thirds of Singapore’s land surface

with the completion of the Marina, Punggol and Serangoon Reservoir. In the long run, the water

catchment area will increase from two-thirds to 90% of Singapore’s land area. Most of this will

be made up of unprotected catchments which consists of land where development is allowed,

for example, for residential, commercial and non-pollutive industrial purposes.

Marina Barrage, Singapore’s 15th reservoir, the Marina Reservoir

2. Imported water

However, Singapore by itself is only able to supply half the nation’s water supply. Another

50% of the nation’s supplies are imported from its neighboring country, Malaysia. The contract

between Singapore and Malaysia is due to expire in 2061 and Chief Executive of the Public

Utilities Board stated that, “We are preparing for the day that should the water agreement

expire, we should be ready to fulfill our own needs”. Furthermore, George Madhavan, the

spokesperson of Public Utilities Board mentioned that “Without secure and reliable access to

water in Singapore, business will not come”.

3. NEWater

NEWater is Singapore’s success story and the pillar of its nation’s water sustainability.

NEWater is a high-grade reclaimed water treatment plant using domestic wastewater which is

then further purified using advanced membrane technology and ultra-violet disinfection, which

makes it ultra-clean and drinkable.

Currently, Singapore’s four NEWater plants are able to contribute 30% of the nation’s

current water needs. It is foreseen that by 2060, NEWater will be able to meet up to 50% of

Singapore’s future water needs.

History of NEWater

- NEWater was first introduced by PUB (Public Utilities Board) in the 1970s

- In 1998, a NEWater study was successfully conducted to determine the suitability of

using NEWater as a source of raw water to supplement Singapore’s water supply

- In May 2000, the first NEWater plant was constructed

Location of NEWater Visitor Centre in Singapore

NEWater Technology Treatment Process ( Step I – Step IV )

I. Microfiltration (MF)

The first stage of the process is called Microfiltration where the treated utilized water is

passed through a membrane. Suspended solids, colloidal particles, disease-causing microbes,

and protozoan cysts are filtered out and retained on the membrane surface. The filtrate contains

only water, dissolved salts and organic molecules.

II. Reverse Osmosis

The second stage of the NEWater production process is known as Reverse Osmosis (RO)

in which a semi-permeable membrane is used. The semi-permeable membrane has very small

pores, allowing only very small molecules like water molecules to pass through. Consequently,

undesirable contaminants such as bacteria, viruses, heavy metals, nitrate, chloride, sulphate,

disinfection by-products, aromatic hydrocarbons, pesticides and others cannot pass through the

membrane. Hence, the processed water is free from viruses, bacteria and contains negligible

amount of salts and organic matters.

III. UV Disinfection

At this stage, the water is already of a high grade water quality. This stage of the NEWater

production process acts as a further safety back-up to the RO. In this stage, ultraviolet or UV

disinfection is used to ensure that all microorganisms are inactivated and the purity of the

product water guaranteed.

IV. Before Storing

Before Storing NEWater in Water Tanks, the pH value of the NEWater is to be are balanced

with the addition of some alkaline chemicals to restore the acid-alkali or pH balance. After the

pH balance has been achieved, the NEWater is now ready to be piped off to its wide range of

applications.

Quality of NEWater

Color

Suspended Particles

Level of Organic Substances

NUS Laboratory has been directing extremely thorough

examinations of NEWater to guarantee that the water

quality is up to standards. 20,000 examinations in the

course of the recent two years have been directed and

these have determined that NEWater is cleaner than

(Public Utilities Board) PUB water. Physically, NEWater

is clear and shining. The river sources and reservoir

water has more color as they contain more minerals and

natural substances.

The river sources and reservoir water also contain more

suspended particles. These particles are washed into

rivers and reservoirs by rainfall running off the ground.

NEWater then again is clearer, much clearer than PUB

water.

Bacteria Count

4. Desalinated Water

The organic substance of NEWater is less than one-tenth

of PUB water causing industry users to find NEWater to

be appealing. For example, currently, the wafer

fabrication plants take the PUB water and process it to

reduce the organic substance to a level that is

acceptable for their operations. Starting from next year,

the wafer fabrication plants in Singapore will utilize

NEWater instead of PUB water because NEWater is

cleaner than PUB water, and is more appropriate for their

operations.

The bacteriological quality of water is a very important

variable for consumable use. Pathogenic bacteria are

harmful to health and are found in animal waste and soil.

Rain that falls onto the ground will carry the bacteria into

the rivers and the reservoirs. Bacteriological quality of

NEWater is as good as PUB water due to the fact that

presence of bacteria and virus is not detectable, thereby

meeting the World Health Organization's Standards

Treating seawater is the most energy-intensive and most expensive source of water to

produce among the treatment methods. Two desalination plants with a combined capacity of

100mgd can now meet 25% of water needs in Singapore. It is anticipated that desalinated water

can meet up approximately 30% of Singapore’s future water needs.

Possible problems to the system

In our times, our waste water treatment may be very advanced now but that does not

mean that the system is perfect. There are also many problems relating to the waste water

treatment system that are currently operational in our country. Some of the problems with

wastewater treatment plants are listed below.

1. Bad odour coming from sewage treatment plants

One of the more notable problems concerning sewage treatment plants are the pungent

odour coming from them. This is the problem affecting those that are living near a sewage

treatment plant. The main cause of odour problems is primary due to the presence of hydrogen

sulphide which is a colourless gas that smells similar to rotten eggs. This happens when the

solids from the wastewater accumulates at the bottom and sides of the tank which leads to

bacterial growth which produces odour. All these could lead to treatment deficiencies and also

cause the staffs that are working there to have an unhappy working environment.

Solution:

A solution to this is to increase the oxygen supply to the water treatment process as increasing

the oxygen supply ensures that the aerobic bacteria have sufficient oxygen they need to digest

all the organic material in the sewage thus leading to lesser odour release. Another solution is to

ensure the wastewater is circulating effectively and also efficiently to ensure dissolved oxygen is

penetrating to the very bottom of the aeration basin as it is where the odour-causing anaerobic

digestion occurs. By circulating wastewater effectively, it can equally spread dissolved oxygen

throughout the aeration basin and in return will promote odour-free aerobic digestion.

2. Insufficient space for new water treatment plants

This problem is related more to places like Singapore where land is scarce. With the

population of Singapore growing larger and larger, the older waste treatment plant will have a

hard time to deal with all the new extra volume of waste coming in. Not only that, but they also

do not have the space necessary to build another new waste treatment plant as their country is

very small and most of the land has been used up. They would need to find a way to retrofit

their existing waste treatment plant with newer technology to deal with more wastewater in the

near future.

3. Aging infrastructure

This problem happens more frequent in still developing countries. This is a real treat to the

system as it could lead to a shutdown of the entire system if most of the waste treatment plants

fail at a certain point due to their age. An example would be the walls of an old aeration tank

that’s starting to crack due to its age and if it’s not repaired in time it would lead to the wall

crumbling and breaking apart due to the stress caused by all the wastewater putting pressure

against the wall. But it is not their age that really matters but the maintenance cost that is the

real problem in aging infrastructure. As the water treatment plants get older the higher it is going

to cost the government to constantly maintain it and as a result, more of taxpayer’s money goes

to repairing and maintaining old waste treatment plants when they could be using the money to

do other things.

Recommendation for Future Improvement of Wastewater Treatment

Water contamination can have serious harmful impacts on surrounding communities and

ecosystems. Its effects are mostly ignored until physical evidence can be seen. This causes the

problem to worsen to a critical stage, after which recovery can be difficult or near impossible.

Dumping untreated waste into rivers, lakes and oceans causes global widespread damage.

Over the course of the 20th century, an estimated 123 aquatic species went extinct due to water

contamination in North America alone. Likewise, water contamination causes many health

problems for humans and contributes to the spread of diseases such as dysentery,

salmonellosis, cryptosporidium, and hepatitis. One of the most common causes of water

contamination is through the uncontrollable discharge of wastewater. Our Earth is heading

towards an unsustainable future. Therefore, future improvement and planning on wastewater

treatment is essential to withstand or overcome future problems. Below are the few suggested

improvements that can be applied in wastewater treatment in the future:

1. Using New/Improved Technologies Membrane Bioreactor (MBR)

Membrane systems have been critical to the development of advanced water-

reclamation systems. The development of new and improved systems is likewise

expected to continue. Immersed micro- and ultra-filtration membranes provide

excellent pre-treatment for Reverse Osmosis (RO), which can remove a variety of

dissolved constituents. Furthermore, the development of membrane filtration

systems has led to the development of both advanced water-treatment technology

and Membrane Bioreactor (MBR), which is fast becoming the workhorse of the

water-reclamation industry.

With MBRs, biological-solids retention time increases, making possible more

complete biological treatment and the retention of pathogens including infections.

Treatment with MBR produces a highly clarified effluent that can be more effectively

purified. Thus, treatment with MBR is ideal for producing non-consumable water. For

the reclamation of potable water, MBR must be followed by RO and UV treatment.

Natural Treatment Systems (NTSs)Our fundamental understanding and characterization of processes in natural

treatment systems is also developing, enabling us to exploit natural processes to

enhance water quality. In NTSs, a variety of physical, chemical, and biological

processes function simultaneously to expel an expansion scope of contaminants.

Natural Treatment Systems are progressively being utilized to capture, retain, and

treat storm water, thereby converting this “disturbance” into an important source of

water. These natural systems have the advantage of being able to remove a wide

assortment of contaminants, including nutrients, pathogens, and micro-constituents

such as pharmaceuticals and endocrine-disrupting chemicals. Long proven effective

for treatment of potable water, NTSs are increasingly being used for water

reclamation.

Nanotechnology

Further dramatic improvements are feasible in the near future. Ideas involving

nanotechnology are being researched for higher performing membranes with less

fouling qualities, improved hydraulic conductivity, and more specific transport

qualities. Advances in Reverse Osmosis technology include improved membranes

and configurations, more efficient pumping and energy-recovery systems, and the

development of process technology, such as membrane distillation.

Microbial Fuel CellsWith microbial fuel cells, a potential breakthrough technology, electrical energy can

be extracted directly from organic matter present in the waste stream by utilizing

electron exchange to capture the energy produced by microorganisms for metabolic

processes. First, microorganisms are developed as a biofilm on a cathode; the

electron giver is isolated from the electron acceptor by a proton exchange

membrane, which establishes an electrical current. Electrical energy is then

generated through the oxidation of organic matter.

Although this technology is still in the early phases of improvement and significant

advances in process efficiency and financial aspects will be essential, it has the

potential to produce electrical energy directly from organic matter in the waste

stream.

2. Urine-Separating Toilets

The development of urine-separating toilets and technologies for treating urine to

produce hygienic fertilizer products is a key to managing nutrients with minimal requirements for

outside resources, such as additional energy. Urine-separating toilets have already been

developed and continue to be refined, and research on utilizing them for waste management is

ongoing. Struvite precipitation and other processes are already available for producing usable

fertilizer products from separated urine, and efforts are ongoing to enhance the set-up

methodologies. As shown in the diagram above, it can be seen that 3 different tanks are

constructed, which makes the process of waste treatment much easier and efficient.

Learning Outcomes

In completing this assignment, we were all able to learn the importance of wastewater

treatment.

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