The document discusses sewage systems and sewage treatment processes. It begins by defining sewage and explaining why sewage systems are necessary to collect and transport wastewater from residential and commercial areas to treatment plants. It then describes the multi-step treatment process, including primary treatment to remove solids, secondary biological treatment to remove organic matter using microorganisms, and tertiary treatment for disinfection and removal of additional contaminants. The document provides details on various treatment methods and system components, such as screens, sedimentation tanks, aerators, lagoons, and sludge treatment. Case studies from Japan and the Philippines are also presented to compare sewage treatment approaches.

1. Sewage System
Introduction
Sewage is the mixture of water and whatever wastes that contains some ions, solid wastes or harmful
bacteria from the domestic and industry wastes. Sewage system are built in order to collect and transport
wastewater from residential and commercial areas , which typically has a relatively high concentration of
biodegradable organic and inorganic compounds that can be easily utilized by microorganisms for cells
growth and life maintenance . All the sewage or wastewater from the buildings must be treated before
released back to the waterways such as the lake, sea or river. There are no holidays for wastewater
treatment, and most plants operate 24 hours per day every day along the year. Wastewater treatment
plants operate at a critical point of the water cycle, helping nature to prevent water from excessive
pollution.
Figure 1 Sewage from the building flows through the underground sewer pipelines into the public
sewage treatment plant for treatment before released back into the waterways.

2. Installation Process
1. Population Estimation (PE)
First is to estimate the population and capacity flow of the people’s wastewater of the stated area. It is
counted in m3/day at 24 hours operation. As this is to prevent underestimation where the size of the
treatment plant is not able to support the wastewater discharge.
2. Design the size of the treatment tanks and electrical functions
To design and provide the necessary drawing for the proposed treatment system. This is done by the
civil and structure engineers. Whereas mechanical and electrical engineer will be in charge for
electronic connection.
(Example)

3. 3. Design Basis
The treatment plant design must design based on the following raw sewage influent and is able to comply
with the required standards mentioned below:
(Example)

4. * Influent - current wastewater treated result
* Effluent Discharge - Malaysia industrial regulation standard (must be followed)
4. Test-run of the whole treatment plant
To undertake the testing and commissioning works. This is to ensure the performance of the treatment
is guaranteed to comply with discharge specification.
(Example-Biomass Monitoring)

6. Most treatment plants have Primary Treatment, Secondary Treatment and Tertiary Treatment.
Primary treatment is to remove solid and some organic materials. It consists of:
1. Screening: to remove large material such as stone or rubbish, that could block the tank inlets.
2. Grit Chamber: to remove the grit
3. Sedimentation: sludge settles down and will be pump away, while oil floats on top and are skim
off
Secondary treatment uses biological process to remove the dissolved organic matter that could not be
screen in the primary treatment. These biological options include:
1. * Activated Sludge
2. * Trickling Filters
3. * Lagoons
After passing through primary and secondary treatment, wastewater is disinfected using chlorine ,UV
light or other disinfecting compounds. Tertiary treatment includes the process of removing nutrients
such as nitrogen, phosphates, and carbon absorption to remove chemicals. These process consist of
physical, chemical or biological method.
After completing the primary and secondary treatment, the end product will be called as sludge. It will go
through further treatment which is sludge treatment to reduce the water content in it. As this may save lots
of space during storage and easy transportation.

7. *Activated Sludge: Use microorganisms to break down organic matter with aeration and then
allows solids to settle out. Bacteria that contained “activated sludge” are continually recirculated
back to the aeration basin to increase the rate of organic decomposition.
*Trickling Filters: A biological process that uses coarse media contained in a tank that serves as
a surface on which microbiological growth occurs. Wastewater trickles over the media and
microorganisms remove the pollutants. Trickling filters are followed by settling tanks to remove
microorganisms that wash off or pass through the trickling filter media.
*Lagoon: A wastewater treatment that uses ponds to treat water. They rely on the interaction of
sunlight, algae, microorganisms, and oxygen to break down the organic matter.

8. Sewage Treatment Process
Sewage treatment process is divided into three phases: Primary treatment, Secondary treatment and
Tertiary treatment.
A – Taking the wastewater away.
B - Screening - To remove floating objects, large solids (those with a diameter more than
2cm ) and grit (heavy solids ) that may damage the equipments.
C – Primary Treatment - Wastewater will than transfer into a large settlement tank called clarifier.
- In this circular tank, a large arm will slowly move around the tank and
bubbles will be released and rise to the surface of water carrying the
suspended solids. The sludge will be floated on the top surface of water and
will be collected by sludge spiral scoop for removal from the unit.We called it
“Sludge Treatment”.
- The sludge will then transferred to the sludge holding tank and further
dewatering.
-The clarified wastewater will overflow to the next tank for biological
treatment for next stage of the treatment process.

9. D – Secondary Treatment - In this treatment it uses biological unit process to remove dissolved organic
matter.
- The wastewater is transferred into rectangular tanks called ‘aeration lanes’.
- Oxygen is introduce into the system to encourage the bacteria to digest the
organic matter.
E – Final Treatment / - After the sludge settles to the bottom of the tank, the treated wastewater will

10. Tertiary Treatment be transferred to the final settlement tank.
- Later on, chemicals are also added to remove nutrients and toxic substances
that contains heavy metals. This also includes balancing the pH level to the
required state.
- Effluent discharge from the tertiary treatment are of high standard and are
suitable for reuse.
F – Sludge Treatment - The sludge that has been collected from the beginning of the process will
then go through thickening process, dewatering process and lastly drying
process.
- The final product of the sludge is called as sludge cake.
- Most of it is recycled for agricultural fertilizer usage or it can also be used to
generate energy.
- Other than that it is mostly used as a landfill material.
G – Treated clean water are sent back to the river.

11. Sewage Treatment Methods
A) Physical Unit Operation
• To remove inorganic and organic solid from the wastewater.
• It implies solid-liquid separation process and also called as sedimentation.
• They uses the concept of gravity to aid sedimentation for the solid-liquid separation
process.
• So they uses the physics’ law for designing a system to remove solids from liquids. For
example, sedimentation tank.
• Gas transfer is also an important physical unit operation for the removal of iron,
manganese, sense of taste and odor by using the aeration way.
• Example: Sedimentation, screening, aeration, filtration, flotation, skimming, de-
gasification, equalization and so on.
B) Chemical Unit Process
• It consists of using chemical reaction to improve the quality and purification of water.
• Including chemical coagulation, chemical precipitation, chemical oxidation, chemical
adsorption, disinfection so on and so forth.
Physical & Chemical Biological
-Screens & grit removal
-Sedimentation
-Sludge Thickeners
-Sludge dewatering
devices
-Ion-exchange
-Multimedia filtration
-Adsorption
-Reverse osmosis
-Ultrafiltration
-Membrane bioreactors
Aerobic Anaerobic
-Contact Beds
-UASBs
-Sludge digesters
-Anaerobic Ponds
Suspended Growth Attached Growth
-Activated sludge
-Extended aeration
-Aerated lagoons
-Waste stabilization
-Ponds
-Trickling filters
-Rotating bio discs
-Land treatment
-Constructed wetlands
-Vermiculture

12. • Examples of type of chemical used:
Name of chemical Usage
• Poly Aluminum Chloride (PAC) • Act as a coagulant
• Sodium Hydroxide (NaOH) • To control the pH level
• Urea • Act as a food for the bacteria
• Sodium Chloride (NaCI) • Chlorine, kills harmful bacteria
• Polymer • Act as flocculant
C) Biological Unit Process
• Mostly used at the secondary treatment. It is because most of the solid are organic. So
biological unit process is the most cost effective and efficient to be used.
• BOD and COD are organic matters that are excreted from the human body which
normally comes from the food that they have consumed or food waste.
• The organic matter that is present in the sewage water is highly degradable. Where BOD
and COD ratio is very high. Hence by using biological process it is more efficient to
dissolve them.
• Microorganisms, mostly bacteria assists biochemical decomposition of wastewaters to
remove pollutants and produces stable end products.
• Biological unit process can be divided into two, which are aerobic and anaerobic, they
reacts based on the availability of dissolved oxygen.
• Oxygen is introduced into the wastewater where it supplies oxygen to the
microorganisms and the microorganism feeds on the organic matter and then produces
carbon dioxide.
• During this period aeration continues until complete biodegradation of BOD and at this
stage some microorganisms will die because lack of food and will help reduce the
volume of settling sludge.
• After the sludge concentration is reached, the aerators are shut off and the settling
period begins.
• Later on solid separation takes place, leaving clear treated effluent above the sludge
blanket.

13. • Example:
- Aerobic : Activated sludge treatment, trickling filtration, oxidation pond, lagoons,
aerobic digestion.
- Anaerobic : Anaerobic digestion, septic tank, lagoon.
Flow Chart between Sewage Treatment Process and the Sewage Treatment Methods
Preliminary
Treatment
dd
Primary
Treatment
dd
Secondary
Treatment
dd
Tertiary
Treatment
dd
Physical Unit
Operation
Physical Unit
Operation
*Biological /
Physical Unit
Process
*Chemical /
Biological
Unit Process
Removal of solid rubbish, grease, oil
and also removal of settleable solids
and floatable matters.
Removal of solid rubbish, grease, oil
and also removal of settleable solids
and floatable matters.
To remove
organic
matters.
To remove
organic
matters.
To remove
nutrients
and
pathogens.
To remove
nutrients
and
pathogens.
*Mainly used.

14. Sludge Treatment System (In Details)

15. Figure 2 Sludge Treatment Process
Sludge is the solid waste that are separated from the liquid waste through wastewater treatment.
Through sewage treatment process, whether from the start of the process until the end of the
process, can produce significant amounts of sludge that require further treatment and put to good
use. Untreated sludge is a significant environmental and public health hazard. So, sludge must be
treated before being disposed off in an environmentally safe manner.
A Thickening Process -Gravity thickener uses gravity to thickened the primary sludge from the
primary clarifier and then the thickened sludge is stabilized in the
anaerobic digester.
-Mechanical thickener uses a polymer to thicken the secondary sludge
before being stabilized in the digester.
B Digesting Process -Treats the sludge using a process called “Anaerobic Digester”.
-This is where the sludge is heated to encourage the bacteria to eat it and
creates biogas that we then burn to create heat, which in turn creates
electricity.
-The gas produces from this process is collected and flared.
-The anaerobic digester further stabilizes the thickened sludge.
C Dewatering Process
(Thermal Destruction)
-The stabilized sludge is dewatered in a screw press or belt press.
- A polymer is added to dry the sludge cake.
D Sludge Storage Area -Treated sludge is temporarily stored in the sludge hopper or yard before
disposal.
E Treated Sludge is
transported for
disposal
-Treated sludge maybe used for land reclamation, in agricultural or
reforestation.
- It may also use as the top soil cover at landfill sites.

16. SLUDGE TREATMENT
1. Sludge Pre Thickener

18. Sewage Treatment Plant
1. Screening.
2. Settling Tank.
3. Aeration
Sedimentation

19. 4.Treatment Lagoon / Pond
4. Aeration System

20. 5. Oxidation Ditch

21. 6. Oxidation Pond
Case Study 1
Fuji Clean Co. Ltd provides domestic and commercial wastewater treatment system using
modern Japanese technology replacing old style septic tanks and sewage treatment
systems. Reliable, transportable sewerage systems producing high quality recyclable
wastewater which can be easily customized for various commercial application.
Name of Company Fuji Clean Co. Ltd
Origin Japan
Main Business Manufacturing, sales and maintenance of on-site wastewater
treatment systems; 1-360m3/day and air pump; 30L-200L/min

23. Process
1. Sedimentation Chamber
Separation of solid waste and removal of greese and oil.
2. Anaerobic Filtration Chamber
Organisms are introduced to digest waste
3. Aerobic Filtration Chamber
Stimulates aerobic bacteria to consume BOD into sludge
4. Storage chamber

24. Act as a room for the bacteria to break down the BOD and with the help of the air-lift
pump to produce oxygen for the bacteria to stay alive.
4. Disinfection chamber
This is used to sterilize the wastewater , to kill harmful bacteria.
Feature
1. Reliable High Performance
Although it is small and compact, it's performance is extremely efficient and reliable and
it produces a very high quality effluent.
Peak-cut System which can effectively cope with shock loadings. The water level in the
system varies according to the presence of any inflow or not.
2. Lower Operational Cost
As Fuji Clean Co. Ltd also uses their own manufactured air blower, which is most energy
efficient. It uses just 52watts compared to 80watts of other blowers. This results in much
lower ongoing operational costs and makes the unit more environmentally friendly.
3. Compact And Easy To Install
This small, compact unit has been specifically designed using advanced Japanese
engineering tools and technology to achieve maximum operational efficiency without
leaving a large footprint on the environment.Due to its light weight and compact design it
is extremely easy to freight and install.

25. Comparison Between Malaysia and Japanese Sewage Treatment System

26. Japanese Malaysia

27. Conclusion
Japan’s sewage treatment system is more compact, as all the people knows that Japan’s
topography is consider as packed and space is limited to built a sewage treatment plant
that is similar as Malaysia’s. They have chosen to produce a small yet efficient sewage
treatment system that suits the needs of the people and assort to their country’s terrain.
Although it is small it can work effectively to purify the water and reuse the treated water
in many ways. We can also see that the steps of process used by Fuji Clean Company is
also similar to ours. In conclusion, our country may learn from them and try to transform
and develop with the aim of space savey concept of sewage treatment system.

28. Case Study 2
Septage management initiatives
Manila, Philippines
a) About Metropolitan Waterworks and Sewerage System (MWSS)
The Metropolitan Waterworks and Sewage System (MWSS) is a government
corporation mandated to provide water supply, sewage, and sanitation services within
Metro Manila and some cities within the province. MWSS is
one of the oldest and most formidable government organizations in the Philippines.
The main aim of this company is to provide a better water services to the citizens.
b) Brief introduction about Manila Water Company, Inc. (MWCI) East Zone
Manila Water Company, Inc. is a Philippine company that holds the exclusive right to
provide water and wastewater services to the eastern side (“East Zone”) of Metro Manila,
under a Agreement between the company and Metropolitan Waterworks and Sewerage
System ("MWSS").
Manila Water has achieved the following in terms of wastewater or “used water”
management. They had initiated the sanitation or septic tank desludging program in the
country with 50 desludging trucks and two septage treatment plants in operation, which
both are the largest septage treatment facility in Asia treatment plant and Asia Leading
sewerage operator. Also with 39 sewage treatment plants that consistently comply with
the effluent standards and regulatory requirements of the Department of Environment .
i) Water treatment applied by Manila Water Company, Inc.
Water Treatment in consists of four processes, which include
coagulation/flocculation, sedimentation, filtration and disinfection.

29. In the first process which is coagulation, flocculation, coagulants and coagulant aids
are mixed uniformly with water to be treated allowing bridging or adhesion of individual
particles into flocs that settle more easily. This is accomplished by a slow, extended
mixing process that converts minute particles into discrete, suspended particles. Balara
Treatment Plant No. 1 has 12 vertical-type, motor-driven flocculators per basin while
Balara Treatment Plant No. 2 has nine flocculators per basin. Detention time is 20
minutes. Balara Treatment Plant No. 2 has 12 basins, each of which has a capacity of 120
MLD. Balara Treatment Plant No. 1, meanwhile, has two basins with a capacity of 140
MLD per basin. Determination of coagulant/coagulant aid dosage to be adopted for plant
use is obtained by conducting a jar test.
The flocs are then made to settle down in the sedimentation basin which is the
second process. This is accomplished by enlarging the area of the basin to reduce the
velocity of the water and adopting a chemical dosage which has a greater settling rate
than the designed overflow rate of the basin.
Detention time is about two hours. After the sedimentation process, third process,
which is filtration will be carried out where water to be treated is passed through a media
consisting of several layers of graded sand and anthracite to screen out all foreign
particles which did not settle down in the sedimentation basin. Detention time is around
20 minutes.
The last process is disinfection where the Balara Treatment Plant uses the chlorination
method of disinfecting water. Chlorine is applied at three points: pre, intermediate and
post-chlorination. Pre-chlorination is applied for taste and odor removal and is usually 0.3
mgl. Intermediate chlorination is for filter aid while post-chlorination is for disinfection
purposes, having dosages of 0.3 and 1.2 mgl, respectively. Finally, water is then sent to

30. distribution by gravity and by pumping.
The rest of Manila Water's concession area that is not connected to a sewerage system
disposes its wastewater into septic tanks. Because septic tanks provide only primary
treatment, they eventually leak out pollution into the groundwater or into municipal
drainage systems, eventually finding its way into our rivers.
Hauled septage from septic tanks are then brought to a Septage Treatment Plant. The
byproducts of septage treatment are treated wastewater (effluent) which are recycled or
discharged safely, and biosolids (organic sludge). The residue is then shipped to Central
Luzon for use as fertilizer, ensuring a natural means of disposal.
c) Brief introduction about Maynilad Water Services Inc. (MWSI) West Zone
Maynilad provides services covering the area of potable water with piped-in water
supply that is safe to be consumed and used for daily life activities. Maynilad will
provide the whole West Zone with 24-hour supply at a minimum pressure of 7 psi
(pounds per square inch) as well as sewerage services for covered areas.
Magallanes Village in Makati and parts of Muntinlupa. Septage treatment system is
provided for the areas not covered under the sewerage services where the wastewater is
disposed through their own septic tanks or sewerage treatment facilities for big
commercial and industrial customers. While, Residential and semi-business customers
who are located outside sewered areas and maintain their own septic tanks may avail of
Maynilad’s septic tank cleaning (desludging).
i) Water treatment plants operated by Maynilad
Maynilad maintains and operates three world-class water treatment plants which are
La Mesa Treatment Plant 1, La Mesa Treatment Plant 2 and Putatan Treatment Plant
which meet the Philippine National Standards for Drinking Water (PNSDW) of the
Department of Health (DOH).
La Mesa Treatment Plant 1 is a conventional-type plant with a maximum design
capacity of 1500 million liters per day (MLD). It was designed by American company
Camp, Dresser and Mckee.
La Mesa Treatment Plant 2 is a pulsator-type plant that has a design capacity of 900
MLD. It was designed by Degrémont, a French company recognized as a world specialist
in water treatment plants.
Putatan Treatment Plant is the largest membrane-based water treatment plant in the
Philippines, and is also the first type used in Philippines to use large-scale microfiltration
and reverse osmosis.

31. ii) Wastewater management of Maynilad Water Services Inc.
Maynilad maintains and operates 20 wastewater treatment plants that process
wastewater and sludge collected from customers. This is to prevent the pollution of
waterways and bodies of water.

32. Septage management process for Manila Water Company, Inc. & Maynilad Water
Services Inc.
Process Manila Water Company, Inc. Maynilad Water Services Inc.
Collection
and
transport
• 91 various sizes of vacuum
tanks
• 25 vacuum tankers and seven mobile
dewatering units (MDUs)
Treatment
and reuse.
• Operates two septage treatment
plants (in Taguig & San Mateo,
Rizal)
• The treatment processes
include:
(i) Primary treatment:
screening, grit & scum
removal
• Operates two septage treatment
plants
(I) In North western part of
metropolis, Dagat-Dagatan
septage treatment plant is a semi-
mechanized treatment system.
Wastewater is treated in waste
stabilization lagoons and

33. (ii) secondary treatment:
• Coagulant-assisted mechanical
dewatering: add polymers &
screw presses the sludge
• Mechanical compaction:
stabilization & reduction of
volume
• The filtrate (liquid component)
is treated further in a
conventional sewage treatment
facility.
• The biosolids are processed to
yield higher value soil
conditioners and then brought
to lahar-affected areas in Tarlac
and Pampanga provinces
(Central Luzon) for composting
and inoculation.
• Treated biosolids are given or
sold to corn, sugarcane and
mango producers in these areas.
wetlands.
(II) In Project 7, Quezon City, the
septage dewatering is done using
screw press with chemical
coagulation to achieve dried
solids with up to 20% moisture
content other than using
sequential batch reactor.
• Another private company collects
and hauls the biosolids to a fertilizer
production facility in Alaminos,
Laguna (Southern Luzon).
• Currently constructing its third
septage treatment plant in the
southern part of Metro Manila.

34. Conclusion for Manila Water Company, Inc. & Maynilad Water Services Inc.
Although both companies in charge of different zones, but still the main source are

35. linked together which come from the 3 dams, Ipo Dam, Angat reservoir and Umiray
river. After all the water sources are gathered, it will be send to the big settling basin
where then only separate and delivered to 2 zones which are West and East zone.
Both of the companies have the same mission and vision which are to provide better
services of potable water, sewerage and sanitation, hoping the citizens can use the best
quality, safe and clean water for drinking and daily usage while at the same time, to
maintain the balance of the environment life cycle and also always relate to the concept
of sustainable development.

36. Possible Problem Faced By The System
1. Size of Domestic
Individual Septic
Tank
This septic tank is
usually located
outside the premises
compound and comprise of two chambers.
De-sludging will be carried out every year to make sure that it is able to function well.
The amount of sludge in septic tank should not exceed the maximum sludge level, it
usually ables to store only third of its total volume.
If the sludge in the storage is surpass the maximum level, sewage retention time will
decrease result in the solid matter is not breakdown completely and released into the
drain when this happen water pollution will occur. Not only that it may also threaten
human health due to the untreated sewage contains virus that will cause diseases.
2. Underestimate Size of Sewage Treatment System
Most of the time developers may want to save cost in sewage treatment system hence
they may require the engineers to built according the estimated population of the area
stated. In the end it may cause sewage treatment disorder and even the wastewater is not
screen properly and thoroughly. Normally professionals may suggest to built bigger and
estimate more that the estimated population to prevent future problems.

37. 2. Broken
Connected
Services
Underground
sewer pipes
comprise two
types of pipe
which is private
connection pipe
and public sewer pipe. Underground pipeline enables every household’s private
connection pipe links to the public sewer pipe.
Blockages in sewer pipe occurs when disposal of object into the toilet or any inlets .
When this happen it will cause blockage in the toilet, between pipes and even manholes
hence overflow will occur.
Other than that broken pipes is also a common problem. This usually occurs when the
quality of the pipe has worn-off over the years and it may also caused by the surrounding
environment.
Recommendation For Future Improvement
1. Encourage 3R
3R consist of reduce, recycle and reuse. For future improvement to sustainable
wastewater treatment is to carry out the concept of 3R. By reducing the use of clean
water we can reuse the treated water for irrigation, agriculture, toilet flushing and also
public parks, by doing this will help to conserve water.
The gas that has been discharged during the sewage treatment process can be used
efficiently. As it contains about 70% methane that can be converted into electricity.
Biogas is produced during anaerobic digestion. One of the benefit is that it can replace
fossil based electricity.
Sludge can be converted into organic fertilizer, there are many advantages of using
organic fertilizer such as greater resistance to disease and insect attack, reduce the
amount of chemical fertilizer used and also increase water holding capacity. Moreover
sludge can be manufactured into bricks and coal, by doing this it saves cost and
encourage environment friendly.

38. 2. Compact Sewage
Treatment System
While nowadays land are
very limited, space savey sewage treatment systems are required to cope with this issue.
A compatible yet efficient sewage treatment is needed, simultaneously this type of
science and technology has been going on in the overseas quite sometime. Hence we
hope that we get to learn from it and transformed our common sewage treatment system
in Malaysia.

39. Learning Outcome
From this project, we have learned how much importance is sewage treatment system is
to us. It is a total miracle to see how sewage is transformed slowly into clean water. They
not only uses the genius physics theories and also magical chemistry equations to help the
process of sewage treatment faster and efficient. Moreover, bacteria are used to break
down the BOD into sludge effectively before sending it to be sterilize. The process
starting from sedimentation, flocculation, chemical treatment, biological treatment,
aeration and settlement are wisely used to give full support during the sewage treatment
process. All the process are so on point where it also reduces unnecessary energy usage
and eliminates the waste of time.
All in all, have you ever thought that what if this type of sewage treatment system has
never exist, it may be human’s worst nightmare. As sewage that are created are not able
to be solved and more and more is produce endlessly. Hence we must be grateful to what
have been invented for us and we must not waste natural resources unnecessarily. From
this we can realise that water has been such a wonderful helper if we have it with us and
without it we will be so in trouble. On top of that our country are encourage to learn more
from overseas countries of how amazing they can treat sewage with different ways
effectively. While upgrading our style of wastewater treatment is also not a bad thing to
do.
Let us be grateful and live a better tomorrow.
Thank you.

40. Reference
http://mwss.gov.ph/?page_id=232
http://www.mayniladwater.com.oh/
http://www.manilawater.com/Pages/Home.aspx
http://watsanexp.ning.com/profiles/blogs/the-separate-/management-system-of-the
baliwagwater-district
http://www.mayniladwater.com.ph/facilities-wastewater.php
http://www.mayniladwater.com.ph/facilities-wastewater.php
http://www.iwk.com.my/do-you-know/sewage-treatment-objectives
http://www.iwk.com.my/do-you-know/sewage-treatment-methods
http://www.fujiclean.co.jp/fujiclean/english/index.html
http://www.fujiclean.com.au/Default.aspx
http://arkitrek.com/http:/arkitrek.com/in-the-shit-a-septic-tank-guide/
http://www.bem.org.my/publication/march-may2005/ENVIRO(IWK3).pdf
http://www.theprospectgroup.com/indah-water-ceo-ir-abdul-kadir-on-wastewater
management-and-sustainability-in-malaysia-81314/