Effluent Treatment Plant

Screening: The raw waste will be first passed through a manual bar screen with 10mm spacing to remove floating suspended matters. The bar screen is cleaned manually by means of rakes. The screenings are disposed off suitably after they are dewatered.

CPI oil separator: After screening waste water enters an oil separator chamber at a particular rise rate. This makes oil float at the top surface which can be skimmed by a skimmer. Then the oil free waste water flows forward for the further treatment.

Waste water basin / Equalization tank: The waste will be then pumped in the equalization tank. The equalization tank is designed for a hydraulic retention time of around 12 hours.

PH correction: The effluent is then taken by gravity into the pH correction tank for neutralization. Acid / caustic is dosed for neutralizing the pH. The pH correction tank is designed for hydraulic retention time of around 720 minutes and is provided with agitator for thorough mixing of waste with alkali.

Solid Contact Clarification: The equalized waste is then transferred to the clarifier by gravity. The waste passed through the draft tube section of the clarifier. In the clarifier Ferrous Sulphate (FeSO4) or Alum as coagulant and Polymer as flocculant are dosed to aid in the precipitation process. In the Solids contact clarifier, chemicals and large quantities of recirculating precipitates are thoroughly mixed and are retained in intimate contact for a prolonged period of time in the draft tube and cone sections of the Solids contact clarifier. The intimate contact between the waste, chemicals and previously formed precipitates cause the chemical reactions to proceed at a rapid rate with a minimum of treating chemicals.   Furthermore, by contacting the water with the great volumes of precipitates in circulation, maximum clarification of the waste can be obtained by the adsorptive -properties of the precipitates, or flocs formed. The sludge scraper in operation continuously moves the precipitates settling on the floor of the Solids contact clarifier, to the central sump where they are concentrated and blown off to waste. The sludge formed in the clarifier is taken for sludge treatment while the overflow is taken for further treatment.

Final PH correction: The clarified effluent is then taken by gravity into the final pH correction tank for neutralization. Acid / caustic is dosed for neutralizing the pH. The pH correction tank is designed for hydraulic retention time of around 720 minutes and is provided with agitator for thorough mixing of waste with alkali. After final pH correction effluent is corrected in the treated water basin and from there as required it can be pumped for the disposal in to the sewer or for further treatment or recycled to the waste water basin.

Sludge Treatment: The underflow from the clarifier having a sludge consistency of around 3 % is then pumped into the thickener and then to the sludge drying bed for dewatering.

Sludge Handling: The sludge from the clarifier shall be collected into the sludge basin by gravity. Sludge Feed Pumps further pump sludge to the sludge thickener. The flocculant solution will be added to facilitate the sludge dewatering. In the thickener sludge consistency of around 6% can be achieved. Thickened sludge is then further transferred to the sludge drying bed. Here the sludge will get dewatered. The dried sludge Cake shall be transferred periodically for Disposal / Landfill 

The over flow filtrate from the thickener will be taken to the Drain Pit and then returned to the waste water basin.