TAN KAI SIN
TAN CHUU YEE
LOW CHEE YING
WONG YUN SHI
CHEONG KHA MAN
ELEY CHONG SHU
used water or liquid that contains impurities or pollutants in the
form of solids, liquids or gases or their combinations.
generated by human due to various activities (daily activities,
commercial activities, industrial activities).
The final discharge of wastewater will normally onto the land
(receiving bodies of water may be ponds, lakes, streams, rivers,
It is harmful and will affect people health if wastewater being
disposed into the environment without any treatment processes.
Wastewaters can be classified
- aka municipal/sanitary wastewater, simply sewage.
- used water which has been discharged from the
residential, commercial and industrial area of a city,
and collected through sewage system.
- generally is 99.9% water and contains only 0.1% of
organic and inorganic solids and also microorganism(bacteria).
- generated by large & medium scale industries.
- manufacturing industries produce a large volume of high
partial reduction or complete removal of
excessive impurities contain in wastewater.
Usually wastewater treatment is mean the
reduction or removal of the solids from
wastewater since impurities are generally due to
the presence of solids in wastewater.
Wastewater treatment methods classified into:
i) physical unit operations
ii)chemical unit processes
iii)biological unit processes
The treatment units are designed to carry out particular
functions on the principles of either one or a combination
of the means employed.
Based on the means used, treatment methods have been
broadly classified as unit operations and unit processes.
- treatment in which the application of physical forces to treat
- Physical unit operation includes screening, mixing, flocculation,
sedimentation, floatation, elutriation, vacuum filtration, heat
transfer and drying.
- treatment in which the removal of pollutants by the
addition of chemicals or the use of biological mass or microbial
- Based on the type of agent used, unit processes can be further
classified as chemical unit process and biological unit process.
Chemical unit process
treatment method in which reduction or removal is brought about by
chemical reaction (adding chemical).
- chemical neutralization: to control or adjust the system pH
- chemical coagulation : to remove colloidal particles by chemical
destabilization and flocculation
- chemical precipitation: to enhance the removal of suspended
solids, phosphorous, heavy metals and Biochemical Oxygen
Demand in specific system conditions
- chemical oxidation: to remove grease, ammonia, Biochemical
Oxygen Demand, Chemical Oxygen Demand and for odor
control in particular requirement
- chemical disinfection: to kill pathogens in influent and treated
Chemical unit process
- expensive due to cost of chemicals that are used and
expenses that arise in handling the large volume of
sludge generated by chemical precipitation.
- if the treatment system is designed to reuse the treated
wastewater, the increase in concentration of particular
constituent requires due attention.
- chemical processes are generally not provided in
conventional treatment of domestic wastewater.
Biological unit process
method which removes pollutants by biological activity
Biodegradable organic substances converted into gases that
escape to the atmosphere and cell tissue are removed by the
Suspended growth process: Activated Sludge Process,
Aerated Lagoon, Oxidation Pond, Aerobic and Anaerobic
Attached growth process: Trickling Filter, Rotating Biological
Contactors, Bio Towers, Up-flow Filters, etc.
the type of combination used from the available unit
operations and processes for treatment of a particular
Normally, a wastewater treatment plant is designed for
either Preliminary Treatment System,
Primary Treatment System,
Secondary Treatment System, or
Tertiary Treatment System.
Preliminary Treatment System
is mainly selected to remove floating materials and large inorganic
particulate matters of wastewater that usually cause maintenance or
operational problems in primary and secondary wastewater treatments.
aka pretreatment in common treatment system.
sump and pump unit: town wastewater is usually collected in a sump
or holding tank and is pumped to the higher levels of treatment units
approach channel: to convey and dampen the flow of wastewater
pumped to treatment plant units
screen chamber: to remove large size of floating materials
grit chamber: to remove suspended settleable solids
skimming tank: to remove excessive oil and grease from the
Primary Treatment System
remove solids and some organic materials.
In this treatment system,
-screen chamber will remove most of the large floating materials
-grit chamber will separate most of the heavy suspended solids
-primary sedimentation/settling tank will reduce 60%-70% of fine settleable
In a conventional treatment plant, settleable suspended organic
matter is removed by primary treatment system in primary
sedimentation or settling tank (PST). Colloidal and soluble
organic content of wastewater is removed in secondary treatment
Secondary Treatment System
aka biological treatment, because biological processes take
place in this treatment.
using microorganism, primary bacteria to convert
biodegradable organic matter contained in wastewater into
simple substances and additional biomass.
The oxygen level in the wastewater will be changed in order
to produce aerobic and anaerobic environment.
About 85% of the suspended solids and BOD can be
removed by a well running plant with secondary
(BOD is used for microorganism to measure the quantities of oxygen in
the oxidation process. The higher BOD of a source of sewage
represents the higher the polluting power of that wastewater.)
There are many types of treatment plants are used to
carry out secondary wastewater treatment. The common
types in our country is oxidation pond. However, the
trend is moving towards to Extended Aeration (EA),
Oxidation Ditch (OD), Rotating Biological Contactors
(RBC), Sequenced Batch Reactors (SBR) and Trickling
Oxidation ponds, aka lagoons/stabilization ponds,
-large & shallow ponds designed to treat wastewater through the interaction
of sunlight, bacteria, and algae.
-consists of two ponds.
-oxidation pond is commonly used in the small communities in our country
due to low operating and construction cost & the temperature in Malaysia is
suitable for the aerobic bacteria as the bacteria can only survive in warm
Extended aeration system used in Malaysia is Fine
Bubble Diffused Air Extended Aeration Systems
FBDAEA will be the trend of wastewater treatment plant in
Malaysia because it does not require a large place and it
is efficience as the sludge is recycled for the further
treatment. Nevertheless, its maintenance cost is
expensive and need technical skill to be maintained and
Tertiary Treatment System
aka Advanced Treatment System
further treatment to reduce and remove the
concentrations of residual impurities in the wastewater
from the secondary treatment system.
The major purpose of tertiary treatment system is to
reduce nitrogen and phosphates which can cause
serious problems when they get into water body by
enhancing the growth of algae blooms.
The tertiary treatment system is normally provided when:
1.the quality of standard treated wastewater (secondary
effluent) is inappropriate for the final disposal requirement.
2.the concentration of leftover organic materials or suspended
solids require further removal for specific reuse of
wastewater after the secondary treatment.
3.the concentration of leftover nutrients is high for final
disposal or reuse of wastewater.
Tertiary treatment is high-priced, so it is normally employed for
treatment of industrial wastewater.
Also known as green technology that the
development and application of products,
equipment and systems used to conserve the
natural environment and resources, which
minimizes and reduces the negative impact of
• efficient for generations to have a good
Reduce effluents and gain the opportunity to re-build soil
with valuable organic matter.
Prevent diseases and retain the high environmental
quality to let people gain a healthy life.
Environment-friendly, consume less energy, cause less
Produces lower amounts of excess sludge.
Able to control their odor problems effectively.
Allows people to become less dependent on groundwater and
surface water sources around the earth, can decrease the
diversion of water from sensitive ecosystems.
Water resource can be reuse to reduce the impact of water
scarcity and pollution.
Reduce the nutrient loads from wastewater discharges into
waterways, reduce and prevent the eutrophication of the
waterways(lakes and streams).
Reduce the pathogens in groundwater and surface water to
improve human health.
In wetland treatment, natural forces (chemical, physical
and solar) act together to purify the wastewater, thereby
achieving wastewater treatment. A series of shallow
ponds act as stabilization lagoons, while water hyacinth or
duckweed acts to accumulate heavy metals. Multiple
forms of bacteria, plankton and algae act to further purify
Advantages of wetland treatment
It is mechanized treatment systems.
Allows for total resource recovery.
Considered as a low-cost technology if sufficient, non-arable
land is available.
Disadvantages of wetland treatment
Affected by the climate.
Some locations may make it unsustainable.
Mechanical problems may include clogging with sprinkler
and drip irrigation systems.
High demand for large area of arable, flat land.
Existing significant odor problems.
Anaerobic bacteria degrade organic materials in the
absence of oxygen and produce methane and carbon
dioxide. The methane can be reused as an alternative
energy source (biogas).
Advantages of Anaerobic Digestion
No, or very low energy demand.
Production of valuable energy in the form of methane.
Low investment costs and low space requirement.
Applicable at small as well as large scale.
Disadvantages Advantages of
Low production of excess sludge.
Low nitrogen and phosphorus requirements.
High treatment efficiencies.
Effluents contain valuable fertilizers (ammonium salts).
Soil Aquifer Treatment
SAT (soil aquifer treatment) is a geo purification system
where partially treated sewage effluent artificially recharges
the aquifers and then withdrawn for future use. By
recharging through unsaturated soil layers, the effluent
achieves additional purification before it is mixed with the
Advantages of Soil Aquifer
Cost is lower.
Remove pathogen efficiently
Operation is not highly technical
Breaks the pipe-to-pipe connection of directly reusing
treated wastewater from a treatment plant.
Disadvantages of Soil Aquifer
Can change the soil and groundwater hydrological
Requires a big area for the infiltration basin.
• capital city of Finland
• contains more than half a million
residents and located at Baltic Sea.
• generate a total of 100 million cubic
metres of wastewater per year
• all the wastewater will be treated by
one wastewater treatment plant which
largest WWTP in the Nordic
treats about 270 000 cubic
meters of daily flow of
an average of 100 millions
cubic meters of wastewater
was taken into use in year
1994 and it has been updated
year 2004, tertiary filter was
Physical Process actived sludge
Biological + Chemical Process
• 95% of phosphorous, 90% nitrogen are removed
• 10 millions m³/y biogas 16 GWh electricity , 26 GWh thermal energy
• 55% self-sufficient in terms of electricity
• 60,000 tonnes of dried waste sludge per year
Low Normal High
≥ Training must be provided to all employees such as operators
≥ Benefits for workers must be provided
≥ Seminars and workshops can be organized and encourage
generation to participate
≥ General knowledge about green technology must be promoted
≥ Recycled resources and renewable materials can be used for
renovation and reconstruction
≥Normal operation of wastewater treatment
≥Installation of ultra-violet treatment facility
≥Complement of CHP engine
≥By using solar energy