Fixed biofilm processes are used in the biological treatment of wastewater. Trickling filters are based on these processes.
A pump transports the wastewater from the supply unit to the upper end of the trickling filter. The wastewater drops down on the trickling filter using a rotary distributor. In the trickling filter there is a fixed bed consisting of special carrier material. On this carrier material there is a thin layer of microorganisms (biofilm). While the wastewater trickles through the fixed bed, the microorganisms clean the wastewater by biological processes. The degradation of organic substances preferably takes place in the upper region of the trickling filter. In the lower region on the other hand, the oxidation of ammonium to nitrate (nitrification) is the predominant process. Subsequently, the wastewater flows into a collecting tank. Two pumps deliver a portion of the collected wastewater to the rotary distributor again (recirculation).
Learning Objectives/Experiments
- Functional principle of a trickling filter
- Recording of concentration profiles
- Creation of a stable operating state
- IIdentification of the following influencing factors
- Flow rate of recirculation
- Volumetric loading of the trickling filter
- Surface loading of the trickling filter
- Comparison of various carrier materials
Specification
- Aerobic biofilm process for the degradation of organic substances and for nitrification
- Transparent trickling filter with rotary distributor
- Speed of the rotary distributor finely adjustable
- Aeration of the trickling filter by natural convection or with compressor
- Recording of concentration profiles is possible
- Secondary clarifier with pump for transporting the return sludge
- All relevant flow rates finely adjustable
- Separate supply unit with wastewater tank and two stirring machines
- Two different carrier materials made of HDPE
Technical data
- Trickling filter
- diameter: approx. 340mm
- height: approx. 1000mm
- capacity: approx. 90L
- Rotary distributor
- max. speed: approx. 2min-1
- Tanks
- wastewater tank: 300L
- collecting tank: 90L
- secondary clarifier: 30L
- Flow rates
- wastewater pump: max. 25L/h
- circulation pumps: 2x max. 25L/h
- return sludge pump: max. 25L/h
- compressor: max. 600L/h
- Carrier material
- specific surface: 180 or 300m2/m3
- Measuring ranges
- flow rate:
- 2…25L/h (wastewater)
- 5…65L/h (recirculation)
- 50…900L/h (aeration)
- 230V, 50Hz, 1 phase
- 230V, 60Hz, 1 phase
- 120V, 60Hz, 1 phase
