SEWAGE WATER TREATMENT.docx

SEWAGE WATER TREATMENT IWK PUTRAJAYA

Introduction Water pollution are caused by various activities ranging from construction activities, factory manufacturing process, agricultural activities and daily human house hold activities. Therefore, sewages are waste that has been contaminated by daily human activities which includes using the bathroom, toilet, washing clothes and the sink in kitchen. This waste water contains harmful substances that may cause harm to the aquatic lives and even humans that may use them. Substances in the waste water may include hair, plastics, debris, clothes, and disease carrying bacteria. Unit Un it op oper erat atio ions ns have have been been grou groupe pedd toge togeth ther er to achi achiev evee vari variou ouss leve levels ls of treat treatme ment nt.. Preliminary or Primary Treatment refers to physical unit operations and is the first stage of  treatment applied to any sewage. Secondary Treatment refers to biological and chemical unit  processes, while while Tertiary Tertiary refers to combinations of all all three.

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Preliminary Sewage Treatment Preliminary sewage treatment is defined as the removal of sewage constituents that may cause maintenance or operational problems with the treatment operations. This includes screening and grinding for the removal of debris and rags, grit removal by sedimentation and flotation for the removal of ecess oil and grease.

Primary Sewage Treatment !n primary treatment screening and sedimentation remove some of the suspended solids and organic matter. The effluent from primary treatment will contain high amounts or organic matter. The treatment flow process is summarised in the flow chart below. INFLUENT

INLET PUMP

SCREEN CHAMBER

"eturn activated sludge

Surplus activated sludge

SLUDGE HOLDING TANK 

EFFLUENT

BELT PRESS

DRYER

#$% dried sludge cake Unit operation 2

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Pump sump Screen chamber  &rit chamber (eration tank  Secondary clarifiers Sludge treatment )io scrubber 

Pum !um The incoming sewer pump by * duty and $ standby pump direct into primary and secondary screen chamber. These pumps are connected to scada systems and monitored $*hrs by plant operators.

Screen c"am#er The raw sewage is distributed between two screen channel for primary and secondary screening. The separated screening then conveyed by screw conveyor into collection bin at disposal area. The screened sewage flows through grit channels for further removal of sand and heavy  particles.

Grit c"am#er &rit removes large settable particles. &rit are separated from water here. The settled grit removed by airlift system and transferred to grit classifier for separation and storage. (fter  the grit channels, the sewage overflows to aeration tank.

Aeration tan$  !n the aeration tanks organic materials are oidised by micro+organisms into non+harmful material. (ir is supplied to cultivate micro+organisms for respiration and digestion with fine  bubble diffused aeration. icro+organisms are suspended with uplift bubbles and the organic substances are oidised to reduce )-. /ine bubbles air diffusers are installed at the bottom of the aeration tanks to provide homogeo!" m#$#g %& %e'%(#o)

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Secondary clari%er The treated water is flowed to clarifier for clarification, where micro+organisms cells are settled and separated from treated water. The treated effluent is overflowed through weir plates and discharged to the nearby river. Sludge settled to the bottom of clarifier and is collected by mechanical scrapper and pumped  back to the aerated tanks for continuous operation.

Sludge treatment The surplus activated sludge in the aeration tanks is wasted by $ numbers of S(S pumps directly to sludge dewatering area. The wasted sludge is flocculated by polymer to form a larger particle for easier thickening and dewatering processes. The dewatering sludge is 0$+ 01% dried. The dewatered sludge than further dried for #$% dry solids by dryer and ready for  disposal.

&io !cru##er The main source of odour is at pump, screenings connection and sludge treatment. (ir is collected and channelled to bio scrubber together by forced ventilated air ducting. The collected odour gas flows through wetted bio media for bio treatment and release to the air.

'onclu!ion /inal effluent must comply to standard (, 2nvironmental 3uality (ct 4Sewage and !ndustrial 2ffluents5 before being sent to the river ecept for the following6+ a.  b. c. d.

)iological oygen demand within range of $7 o8 for 9 days must be less than 07mg:l. Suspended solids must be less than 97mg:l. -il and grease 8hemical oygen demand must be less than 97mg:l.

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(A)AR*+US WASTE Introduction ;a