The document discusses trickling filters, which are used in sewage treatment to remove suspended solids and dissolved organic loads from wastewater. Trickling filters use microbial populations attached to a filter media to break down organic matter. They consist of a rotating arm that sprays wastewater over a rock or plastic media, with wastewater collected below for further treatment. Trickling filters can be designed as low or high rate systems, with high rate filters having greater organic loading, hydraulic loading, and recirculation ratios compared to low rate filters. Operational issues include ponding, odors, and fly nuisance that can occur if the filters become anaerobic or clogged.

1. TRICKLING FILTER
SHILPA PATIL

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)

6. TRICKLING FILTERS

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)

17. ANY
QUESTIONS ?
THANK YOU