LIQUID WASTE MANAGEMENT
Sewage Treatment Plant
Sewage Treatment Plant (STP) is the unit where waste water is treated and processed for the purpose of safe discharge of water into water bodies.Sewage treatment consists of various physical, chemical, and biological processes that are used to remove contaminants and produce treated wastewater (or treated effluent) that is safe enough for release into the aquatic environment.
Sewage Treatment Plant of JK Paper Mills
COLLECTING SEWAGE WATER
Waste water is collected in four Pits 1 km away from each other.
Pit No. 1- Chandili
Pit No. 2- B-Type quarters
Pit No. 3- Airtel Tower
Pit No. 4- E.S.I Hospital
Sewage Water is pumped from the pits to the Sewage Treatment Plant through Automatic pumps.
Sewage water collected from pits
PROCESSING OF SEWAGE WATER
1. Separation of large objects
Screening is the first stage of water treatment process. Screening removes large objects like nappies, sanitary items, cotton buds, broken bottles, plastics and rags that may block or damage equipment.The water is made to pass through bar screens which removes the large objects.
2. Oil and grease removal
Water is collected in the Oil and Grease Chamber after screening. The water is left undisturbed for some time so that oil and grease floats on the surface and the water accumulated at the bottom is collected in another tank i.e. equalisation tank.
In equalisation tank air is pumped through air blowers to form a homogeneous mixture. The capacity of equalisation tank is 735 cubic metres.
Then water is transferred to anoxic tank where the process of de- nitrification is done by agitators. De- nitrification is done to decompose oxygen from oxides of nitrogen (NO2 , NO3 ) to reduce the growth of bacteria present in the water. The capacity of anoxic tank is 630 cubic metres.
Then the water is moved to the aeration tank having a capacity of 1350 cubic metres .In this tank air is given through air blowers for micro biological growth of bacteria which degrade waste water contaminants and maintain BOD (Biological Oxygen Demand) and COD (Chemical Oxygen Demand) of the water.
Flocculation refers to the process in which fine particles are caused to clump together to form floc. In the process lime, alum and polyelectrolyte are added. Polyelectrolyte helps in formation of floc while lime is used to maintain the pH of water to 7+. This process is done in flocculation chamber with a capacity of 46.5 cubic metres .
7. Tube settler
In the tube settler tank the sludge in the form of floc settles down at the bottom and the water on the top is made to flow to the next tank through drain wall. The capacity of tube settler tank is 338 cubic metres .
Sludge used as manure
The sludge which is left at the bottom is moved to Sludge holding tank and then Centrifuged to separate moisture from it. The solid sludge is then used as natural manure in the gardens.
Chlorination is done by Using Sodium Hypochlorite (NaOCl) as it is more effective than Chlorine gas. Sodium hypochlorite produces residual disinfectant and kills all the germs in the water.
9. Filter feed tank
The clarified water is passed to the filter feed tank with a capacity of 178 cubic metres . From here the treated water is pumped to the carbon and sand filters, where the suspended solids, colour and odour will be removed.
10. Dual Media filter and Activated Carbon Filter
The treated water is pumped from filter feed tank to carbon and sand filters. In this chamber the suspended impurities and odour is removed. The treated water will be passed to the UV sterilizer or Ozone for disinfection process.
11. Treated water Tank
From this tank the Treated water is Supplied to JK Paper Mills for make-up of fresh water consumption and also discharged into the river.
In this water:
PH: 7.2 - 8.0
TSS : <20 ppm (Parts Per Million)
COD : <50 ppm (Parts Per Million)