Trickling filter ppt
- 2. OVERVIEW OF SEWAGE TREATMENT PLANT Preliminary treatment Primary treatment Secondary treatment Tertiary treatment
- 3. TYPES OF FILTERS • CONTACT BEDS • INTERMITTENT SAND FILTERS • TRICKLING SAND FILTERS • IT IS USED TO REMOVE THE SUSPENDED SOLIDS & THE DISSOLVED ORGANIC LOAD FROM THE WW BY USING MICROBIAL POPULATIONS. THE MICROORGANISMS ARE RESPONSIBLE FOR DEGRADATION OF THE ORGANIC MATTER
- 4. BIOLOGICAL PROCESSES• SUSPENDED GROWTH PROCESS • IF THE MICRO-ORGANISMS ARE SUSPENDED IN THE WW DURING BIOLOGICAL OPERATION THEN PROCESS IS KNOWN AS SUSPENDED GROWTH PROCESSES • ATTACHED GROWTH PROCESS • PROCESS IN WHICH THE MICRO-ORGANISMS THAT ARE ATTACHED TO A SURFACE OVER WHICH THEY GROW IS KNOWN AS ATTACHED GROWTH PROCESSES • COMBINE PROCESS • THESE CONSISTS OF BOTH ATTACHED GROWTH AS WELL AS SUSPENDED GROWTH PROCESSES Bio-film Or Slime layer Bacteria Liquid Supporting medium (Stones)
- 5. TRICKLING FILTER THEORY • Purification by aerobic decomposition of organic matter •A biological film is formed around filtering media by micro-organisms •Outer portion of this film is called as Slime layer •As thickness of slime layer increases •It creates anaerobic environment near to the surface of filtering media •Micro-organisms goes into endogenous phase of growth and loose their ability to cling to media surface •Shearing action of sewage •Sloughing (the break up of biomass from slime layer)
- 7. TRICKLING FILTER COMPONENTSTF CONSISTS OF MAINLY FOLLOWING PARTS/COMPONENTS: •A rotating arm that sprays wastewater over a filter medium by spray nozzels •Filter media: rocks, plastic, aggregates or other materials are used. size of material (25 mm to 75 mm) •Under drainage system: The water is collected at the bottom of the filter for further treatment.
- 8. TRICKLING FILTERS Effluent Influent •Filter walls: Walls are made honeycombed to circulate the air. Some times ventilation duct is provided •Depth: Depth of media is 1.8 to 2.4m •Honeycomb structured wall is provided for circulation of air.
- 9. TYPES OF TRICKLING FILTER Two Stage High Rate Trickling Filter Recirculation flow Alternate return A part of effluent recirculated Single Stage High Rate Trickling Filter intermediate1st 2nd effluent effluent Recirculation flow Recirculation flow Conventional or Low Rate Trickling Filter
- 10. TRICKLING FILTERS DESIGN CONSIDERATION • HYDRAULIC LOADING • IT IS RATIO OF DISCHARGE OR FLOW RATE TO THE SURFACE AREA • UNITS – CUBIC M/SQ. M/DAY • ORGANIC LOADING • IT IS RATIO OF BOD LOAD TO VOLUME OF FILTER MEDIA. • ORGANIC LOADING = (Q X BOD5)/V • THEREFORE , V = BOD5 X Q/ ORGANIC LOADING • UNITS- KG OR GM. OF BOD/ M3 OF VOLUME/D • EFFICIENCY Organic loading in kg/ha-m/day
- 11. V=FILTER VOLUME IN HECTARE-METER F=RECIRCULATION FACTOR TRICKLING FILTERS DESIGN CONSIDERATION • EFFICIENCY (HIGH RATE TRICKLING FILTER) N= EFFICIENCY IN % Y=TOTAL ORGANIC LOAD IN KG/DAY V=FILTER VOLUME IN HECTARE-METER F=RECIRCULATION FACTOR • RECIRCULATION FACTOR (HIGH RATE TRICKLING FILTER) R= VOLUME OF SEWAGE RECIRCULATED I= VOLUME OF RAW SEWAGE R/I =RECIRCULATION RATIO
- 12. OPERATIONAL TROUBLE IN TRICKLING FILTERS • PONDING:- • EXCESSIVE ORGANIC LOADING WITHOUT A CORRESPONDING HIGHER RECIRCULATION RATE • USE OF MEDIA WHICH IS TOO SMALL • CLOGGING OF UNDER DRAIN SYSTEM • NON-UNIFORM MEDIA SIZE OR BREAKING UP OF MEDIA • ASH OR DEBRIS IN FILTER VOIDS • PONDING CAN CAUSE ODORS AND DECREASE FILTER EFFICIENCY.
- 13. OPERATIONAL TROUBLE IN TRICKLING FILTERS • ODOUR NUISANCE:- • SINCE THE TRICKLING FILTER IS AN AEROBIC PROCESS, NO SERIOUS ODORS SHOULD EXIST. IF FOUL ODORS ARE PRESENT, ANAEROBIC CONDITIONS ARE THE MOST LIKELY CAUSE. • ANAEROBIC CONDITIONS USUALLY PREDOMINATE NEXT TO THE MEDIA SURFACE. IF THE SURFACE OF THE SLIME GROWTH IS AEROBIC, ODORS SHOULD BE MINIMAL. • IF ODORS ARE PRESENT, CORRECTIVE ACTION SHOULD BE TAKEN IMMEDIATELY OR THE CONDITION COULD GET WORSE. • HYDROGEN SULPHIDE GAS IS THE MAIN REASON OF ODOUR AND TO MINIMIZE IT SEWAGE SHOULD BE CHLORINATED.
- 14. OPERATIONAL TROUBLE IN TRICKLING FILTERS • FLY NUISANCE:- • THESE ARE TINY, GNAT-SIZE FLIES ARE CALLED PSYCHODA. THEY ARE OCCASIONALLY FOUND IN GREAT NUMBERS, PREFERRING AN ALTERNATE WET AND DRY ENVIRONMENT FOR DEVELOPMENT. • LAY THEIR EGGS IN PONDED WATER. THE FLIES ARE MOST FREQUENTLY FOUND IN LOW OR STANDARD RATE FILTERS WITH AN INTERMITTENT DOSING SYSTEM. • FLUSHING OR WASHING THE SIDE WALLS OF THE FILTER BY OPENING THE FLAP VALVE AT THE END OF THE DISTRIBUTOR ARM.
- 15. TRICKLING FILTER DESIGN VALUES PARAMETER LOW RATE TRICKLING FILTER HIGH RATE TRICKLING FILTER HYDRAULIC LOADING (CU. M/SQ. M/DAY) 1-4 10-40 ORGANIC LOADING (KG BOD/CU. M/DAY) 0.11-0.37 0.37-1.85 DEPTH (M) 1.5-3 1-2 RECIRCULATION RATIO 0 1-4 EFFLUENT QUALITY FULLY NITRIFIED NITRIFIED ONLY AT LOW LOADING
- 16. TYPES OF HIGH RATE TRICKLING FILTER BIO FILTERS (1.2M-1.5M DEPTH) ACCELO FILTERS (1.8M-2.4M DEPTH) AERO FILTERS (GREATER THAN 1.8M)