Changes

<small{|style="float: left;"|{{Language-title />box|english_link=Trickling_Filter|french_link=Lit_bactérien|spanish_link=Filtro_Percolador|hindi_link=coming soon|malayalam_link=coming soon|tamil_link=coming soon | korean_link=coming soon | chinese_link=Coming soon | indonesian_link=Coming soon | japanese_link=Coming soon}}<!-- table at top of page with logo, picture, Application level, Management level, and input-output tables -->|}

sys2=[[Blackwater Treatment System with Infiltration|56]]|sys3=[[Blackwater Treatment System with SewerageEffluent Transport|67]]|sys4=[[Blackwater Transport to (Semi-) Centralized Treatment System |78]]|sys5=[[Sewerage System with Urine Diversion |89]]|

Input1=Blackwater|Input2=Greywater |Input3= Brownwater | Input4= Effluent |Input5=|

|[[Image:Trickling_filter.png |right|300px500px]]

The Trickling Filter '''A trickling filter is filled with a high specific surfacefixed-area material such as rocksbed, gravel, shredded PVC bottles, or special pre-formed filter-material. A material with a specific surface area between 30 and 900m2/m3 is desirablebiological reactor that operates under (mostly) aerobic conditions. Pre-treatment is essential to prevent clogging and to ensure efficient treatment. The pre-treated settled wastewater is continuously ‘trickled’ or sprayed over the surface of the filter. Organisms that grow in a thin bio-film over As the water migrates through the surface pores of the media oxidize filter, organics are degraded by the organic load in biofilm covering the wastewater to carbon dioxide and water while generating new biomassfilter material.'''

<br>The trickling filter is filled with a high specific surface area material, such as rocks, gravel, shredded PVC bottles, or special pre-formed plastic filter media. A high specific surface provides a large area for biofilm formation. Organisms that grow in the thin biofilm over the surface of the media oxidize the organic load in the wastewater to carbon dioxide and water, while generating new biomass. The incoming pre-treated wastewater is sprayed ‘trickled’ over the filter , e.g., with the use of a rotating sprinkler. In this way, the filter media goes through cycles of being dosed and exposed to air. However, oxygen is depleted within the biomass and the inner layers may be anoxic or anaerobic.

===Design Considerations=== The filter is usually 1 to 3m 2.5 m deep , but filters packed with lighter plastic filling can be up to 12m 12 m deep. The ideal filter material is low cost and durable, has a high surface to volume ratio, is light, durable and allows air to circulate. Whenever it is available, crushed rock or gravel is the cheapest option. The particles should be uniform such that and 95% of the particles them should have a diameter between 7 and 10cm. Both ends of the filter are ventilated to allow oxygen to travel the length of the filter10 cm. A perforated slab that allows the effluent material with a specific surface area between 45 and 60 m2/m3 for rocks and excess sludge 90 to be collected supports the bottom of the filter150 m2/m3 for plastic packing is normally used.

Larger pores (as in plastic packing) are less prone to clogging and provide for good air circulation. Primary treatment is also essential to prevent clogging and to ensure efficient treatment. Adequate airflow is important to ensure sufficient treatment performance and prevent odours. The underdrains should provide a passageway for air at the maximum filling rate. A perforated slab supports the bottom of the filter, allowing the effluent and excess sludge to be collected. The trickling filter is usually designed with a recirculation pattern for the effluent to improve wetting and flushing of the filter material. With time, the biomass will grow thick and the attached layer will be deprived of oxygen; it will enter an endogenous state, will lose its ability to stay attached and will slough off. High-rate loading conditions will also cause sloughing. The collected effluent should be clarified in a settling tank to remove any biomass that may have dislodged from the filter. The hydraulic and nutrient loading rate (i.e. , how much wastewater can be applied to the filter) is determined based on the characteristics of the wastewater, the type of filter media, the ambient temperature, and the discharge requirements.

- Can be operated at a range of organic and hydraulic loading rates. <br> - Efficient nitrification (ammonium oxidation) <br>- Small land area required compared to Constructed Wetlands. constructed wetlands| con=- High capital costs and moderate operating costs <br> - Requires expert design and construction. , particularly, the dosing system <br>- Requires operation and maintenance by skilled personnel <br> - Requires a constant source of electricity and constant wastewater flow. <br> - Flies and odours are often problematic. <br> - Risk of clogging, depending on pre- and primary treatment <br>- Not all parts and materials may be locally available locally. <br> - Pre-treatment is required to prevent clogging. <br> - Dosing system requires more complex engineering.

<br>===AdequacyAppropriateness===This technology can only be used following primary clarification since high solids loading will cause the filter to clog. A low-energy (gravity) trickling system can be designed, but in general, a continuous supply of power and wastewater is required. Compared to other technologies (e.g., [[Waste Stabilization Pond|Waste Stabilization Ponds]], T.5), trickling filters are compact, although they are still best suited for peri-urban or large, rural settlements. Trickling filters can be built in almost all environments, but special adaptations for cold climates are required.

This technology can only be used following primary clarification since high solids loading will cause the filter to clog. A skilled operator is required to monitor ===Health Aspects/Acceptance=== Odour and repair fly problems require that the filter be built away from homes and the pump in case of problemsbusinesses. A lowAppropriate measures must be taken for pre-energy (gravity) trickling system can be designedand primary treatment, but in generaleffluent discharge and solids treatment, a continuous supply all of power and wastewater is requiredwhich can still pose health risks.

Compared ===Operation & Maintenance=== A skilled operator is required to monitor the filter and repair the pump in case of problems. The sludge that accumulates on the filter must be periodically washed away to other technologies prevent clogging and keep the biofilm thin and aerobic. High hydraulic loading rates (eflushing doses) can be used to flush the filter.gOptimum dosing rates and flushing frequency should be determined from the field operation. [[Waste Stabilization Pond|WSPs]]), trickling filters are compact, although they are still are best suited for peri-urban or large, rural settlementsThe packing must be kept moist. Trickling Filters can This may be built in almost all environments, although special adaptations for cold climates problematic at night when the water flow is reduced or when there are requiredpower failures.

===Health Aspects/Acceptance=== The odour Snails grazing on the biofilm and fly filter flies are well known problems require that the filter be built away from homes associated with trickling filters and businesses. There must be appropriate measures taken for pre-treatment, effluent discharge handled by backwashing and solids treatment, all of which can still pose health risks. ===Maintenance=== The sludge that accumulates on the filter must be periodically washed away to prevent clogging. High hydraulic loading rates can be used to flush the filter. The packing must be kept moist. This may be problematic at night when the water flow is reduced or when there are power failuresperiodic flooding.

* UUlrich, A. (Ed.), Reuter, S. EPA (2000Ed.), Gutterer, B. [http://water(Ed.epa.gov/scitech/wastetech/upload/2002_06_28_mtb_trickling_filter), Sasse, L.pdf Wastewater Technology Fact Sheet- Trickling Filters, 832-F-00-014]. US [http://www.epa.gov Environmental Protection Agency]Panzerbieter, WashingtonT. Design summary including tips for trouble shooting. * Sasseand Reckerzügel, LT. (19982009). [httphttps://wwwwedc-knowledge.lboro.indiawaterportalac.orguk/sitesresources/indiawaterportal.orgbooks/files/Decentralised_%20wastewater_%20treatment_%20in_%20developing_%20countries_A_%20handbook_%20by_%20BORDA_1998DEWATS_-_Chapter_01.pdf DEWATS: Decentralised Wastewater Treatment Systems (DEWATS) and Sanitation in Developing Countries. A Practical Guide]. BORDAWEDC, Bremen Overseas Research and Development AssociationLoughborough University, BremenLeicestershire, Germany. Provides a short description of the technologyUK.

* Tchobanoglous, GU., Burton, FL. and Stensel, HDS. EPA (20032000). [httphttps://bookswww3.googleepa.comgov/booksnpdes/aboutpubs/Wastewater_Engineering_Treatment_and_Reutrickling_filt_nitrification.html?id=L1MAXTAkL-QC pdf Wastewater Engineering: Treatment and Reuse, 4th EditionTechnology Fact Sheet. Trickling Filters]. Metcalf & Eddy832-F-00-014. U.S. Environmental Protection Agency, New YorkWashington, D. pp 890–930 C. Detailed description and example calculations, US.(Design summary including tips for trouble shooting)