Waste water engineering

♦️ Trickling Filter

🔸 Trickling Filter works on the principle of attached culture system.

🔸 Detachment of attached biofilm from the surface is called Sloughing

🔸 BOD removal efficiency is 75 to 80%

🔸 Types of Trickling Filter

1. Conventional or Standard rate Trickling Filter :-

👉 Depth of filter media :- 1.2 to 2.4 m

👉 Size of media :- 25 to 75 mm

👉 Land required :- More

👉 Hydraulic loading :- 22 to 44 ML/hect/day

👉 Organic loading :- 900 to 1200 kg of BOD/hect-m.

👉 Recirculation system :- Not provided.

2. High rate Trickling Filter

👉 Depth of filter media :- 1.2 to 1.8 m

👉 Size of media :- 25 to 60 mm

👉 Land required :- Less

👉 Hydraulic loading :- 110 to 330 ML/hect/day

👉 Organic loading :- 6000 to 18000 kg of BOD/hect-m.

👉 Recirculation system :- always provided for Increase loading

🔸 operational problems

👉 Psychoda problems :- fly nuisance.

👉 Odour nuisance :- The remedy is Chlorination of sewage.

👉 Ponding problems :- Filters media gets clogged due to growth of alage and fungi and this is called Ponding.

~ Adding chlorine or copper sulphate to the sewage kills alage there by Ponding can be avoided

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