Work procedure for waste water management from homes businesses and industries

Srinivasan

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Sep 7, 2017
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Work procedure for waste water management from homes businesses and industries

Purpose:
To manage water discharged from homes, businesses and industries to reduce the threat of water pollution.

Pre-treatment
Preliminary treatment, Primary treatment, Secondary treatment
Sludge (biosolids) disposal
Water discharged from homes, businesses, and industry enters sanitary sewers
Water from rainwater on streets.

Preliminary Treatment
removes large objects and non-degradable materials
protects pumps and equipment from damage
bar screen and grit chamber

Bar Screen
catches large objects that have gotten into sewer system such as bricks, bottles, pieces of wood, etc

Grit Chamber
removes rocks, gravel, broken glass, etc.

Mesh Screen
removes diapers, combs, towels, plastic bags, syringes, etc.

Measurement and sampling at the inlet structure
a flow meter continuously records the volume of water entering the treatment plant
water samples are taken for determination of suspended solids and DBO
Suspended Solids – the quantity of solid materials floating in the water column

BOD Biochemical Oxygen Demand
a measure of the amount of oxygen required to aerobically decompose organic matter in the water Measurements of Suspended Solids and B.O.D. indicate the effectiveness of treatment processes Both Suspended Solids and B.O.D. decrease as water moves through the wastewater treatment processes

Primary Treatment
a physical process
wastewater flow is slowed down and suspended solids settle to the bottom by gravity
the material that settles is called sludge or biosolids

Sludge from the primary sedimentation tanks is pumped to the sludge thickener. more settling occurs to concentrate the sludge prior to disposal
Primary treatment reduces the suspended solids and the B.O.D. of the wastewater.
From the primary treatment tanks water is pumped to the trickling filter for secondary treatment.
Secondary treatment will further reduce the suspended solids and B.O.D. of the wastewater

Secondary Treatment
Secondary treatment is a biological process Utilizes bacteria and algae to metabolize organic matter in the wastewater
water runs over a plastic media and organisms clinging to the media remove organic matter from the water
From secondary treatment on the trickling filter water flows to the final clarifiers for further removal of sludge.
The final clarifiers are another set of primary sedimentation tanks.
From the final clarifiers the water is discharged back to the River/designated location.
The final clarifiers remove additional sludge and further reduce suspended solids and B.O.D.

Disposal of Sludge or Biosolids
the sludge undergoes lime stabilization (pH is raised by addition of lime) to kill potential pathogens
the stabilized sludge is land applied by injection into agricultural fields

The wastewater plant lab conducts a number of measurements and tests on the water.
suspended solids
temperature
BOD
nitrogen
pH
phosphorus

In addition to test performed at the wastewater lab, an off-site contract lab performs additional tests
heavy metals
priority pollutants
WET (Whole Effluent Toxicity) tests
 
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