Effuelent Cum Sewage Treatment Plants
The individual units of the ETP are as follows:
Physical Treatment:
(a) Screen Chamber: Waste water generated should pass through a bar screen chamber for removal of floating matters.
(b) Collection & Equalization tank: From the screen chamber water should come in to the collection tank. Where it is equalized by air purging grid
system.
Chemical treatment:
(a) Chemical Reaction Tank
From the collection tank water should be pumped in the chemical reaction result with a minimum dose. Polyelectrolyte is also added in this tank to hasten the floc formation process. Mixing of chemicals is done with diffused aeration. Air is provided through diffuser pipes from air
blower.
(b) Primary Tube Settler:
The effluent from the reaction tank should be flows by gravity to the primary settling tank which is a tube settler. Most of the suspended solids & chemical floc settle down in the settling tank. The clear supernatant from the top overflows enters to the biological reactor tank. And chemical settled floc (Sludge) should be drain to the sludge drying beds.
Treatment Scheme of STP (Individual Units & Process):
The conventional method of treatment is physical treatment followed by biological treatment and tertiary treatment to filtration & adsorption
column. Sewage water enters to the screen chamber, screen chamber (manually cleaned removable type), should be provided to screen of large floating collection /equalization tank. The effluent from the equalization tank should be made to re-circulate the effluent to enable the content of the effluent screen, and equalization tank, the over ground STP comprises Bio Reactor and Tube Settler. The overflow from the over
ground Tube Settler flows by gravity into the Disinfection cum treated effluent holding chamber.
The individual units of the STP are as follows:
1. Screen Chamber: The waste water generated should be passed through a bar screen chamber for removal of floating matters.
2. Collection & Equalization Tank: From the screen chamber water should be come in the collection tank, where water will be
equalized by air purging grid system.
Common units and process of ETP cum STP
a) Biological Treatment: Effluent water from secondary tube settler and sewage water from sewage collection enters to the Bio Reactor
Tank. Fluidized Aerobic Bio Media (FAB): In this biological system, it has to be operated 24 hours. The effluent enters the aeration chamber to oxidize the organic to CO2 and H2O by aeration principle. Aeration tank is fitted with suitable capacity of air diffusers to provide a minimum of 2ppm of dissolved oxygen and Bio Media to maintain the perfect contact time for biological reaction and bacteria growth. Tube Settler: Then water should be come from the Bioreactor to secondary Tube Settler where Sludge settled. The settled sludge of the settling tank is moved to the sludge drying beds.
b) Dis – Infection Tank: The water from tube settler should be collected in to the disinfection tank, where shot dosing (1 PPM) of sodium Hypo chlorite is given.
c) Tertiary Treatment Units: Tertiary treatment units like filtration. In the multi grade filter column the TSS Level would be reduced 5-10% and in the activated carbon filter the odor & color of waste water.
Drying & Disposal of Sludge: The biological sludge is collected in sludge Holding Tank. The sludge from the Sludge holding tank is disposed off at outside area or it should be used as manure by further Treating and the filtrate from the sludge holding tank returns to the collection tank.