TYPE OF SEWAGE WATER TREATMENT PLANTS
- activated sludge plant (ASP)
- sequencing batch reactor (SBR)
- submerged aerated filter (SAF)
- suspended media filter (SMF)
- non electric filter
- tricking filter
Activated Sludge Plant (ASP):-
- the activated sludge process is a sewage treatment process in which air or oxygen blown in to raw unsettled sewage to smash the solids develop a biological soup .
- which digest the organic content and pollutants in the sewage.
- these plant does not have a primary settlement chamber.
- in all activated sludge plants once the sewage have been bubbled long enough,excess sewage liquor is discharged into a clarification chamber.
- where live bacteria settle to the bottom, dead bacteria rise to the top and from a crust with a clear liquid in the middle.
- this clean water is then discharged into soak away .
- the activated bacterial sludge are returned to the digestion chamber to re-send the new raw sewage.
Sequencing Batch Reactor (SBR) :-
In this type of technology we take the sewage water from residential drainage . For this we make the chamber for various areas and then it collect in to the pump of certain capacity.
The sewage water from the pump house is pump to the inlet chamber of plant for starting it's process:-
- The sewage water first go through the primary treatment. Which contain fine screen and grit unit
- The fine screen screening up to 6 mm garbage. So first fine screen remove the garbage or solid waste from sewage water .
- which come from pump house then it send to the grit unit or sedimentation unit.
- Where the suspended solid will remove from sewage water.
- This grit unit consist of three mechanism organic pump, grit scraper and rack classifier.
- After this removal of suspended solid raw sewage send to the selector zone through the inlet gates, where anoxic-mix conditions are maintained.
- Also a part of the treated effluent along with activated sludge from aeration zone is recycled here using Return Activated sludge (RAS) Pump.
- As the microorganisms meet high BOD and low DO condition in selector zone, natural selection of predominantly floc forming microorganisms takes place.
- This is very effective in containing all of the known low Bulking microorganisms, which eliminates problem of sludge bulking and sludge foaming.
- This process ensure excellent settling characteristics of the biological sludge also, due to the anoxic/ anaerobic conditions in the selector zone, De- nitrification and phosphorus removal occurs.
- After this process sewage enter into basin . these basins work in sequence and influent flow is distributed using automatic gate provided at the inlet chamber of basin.
- The basins are equipped with air blowers, diffusers, return activated sludge (RAS) pumps, surplus activated sludge (SAS) Pumps, Decanter, Auto valves, programmable logic controller PLC etc.
- All the cycle will be automatically controller with using plc.
- The complete biological treatment is divided into cycle of 3 hrs duration.
- During which all treatment steps take place.
- A basic cycle contain the following phases which take place independently in sequence and then gets repeated:-
- Filling / aeration
- Settling
- Decanting
1.Filling/ aeration :-
- In this process the sewage water fill into basin and simultaneously aerate with air through blower and diffuser.
- Aeration can be regulated to maximize co- current nitrification de- nitrification that takes place and to insure the aerobic uptake of phosphorus previously released during anaerobic operation.
2.Settling:-
- In this process The air blower is turned off and influent to the reactor basin is stopped.
- At this time gentle bio- flocculation initially take place, a solid - liquid interface forms under partial settling conditions.
- Raising sludge does not occur.
3.Decanting:-
- In decanting process decanter remove the treated water from only surface level water.
- the clear supernatant is removed from the basin using a stainless steel decanter.
- during decanter there is no inflow to the basin.
- The movies weir decanter is motor driven and travels slowly from its " park " Position to the designated bottom water level.
- Variable frequency drives are provided to control the rate of movement of the decanter.
- This allow optimum removal over the decant depth without entertainment of settled solid or floating debris.
- After completion of supernatant liquid removal sequence, decanter return to the home position.
- After that all process repeated again.
- Excess sludge at a consistency level of approx 0.8% will be pumped intermittently from SAS pump to sludge sump.
- The sludge from sludge sump is taken for dewatering and finally for its ultimate disposal.
Great Helpfully information.
ReplyDelete