What is the design criteria for trickling filter?
The trickling filter design must evaluate the impacts of recirculation, air draft temperatures and medium. Recirculation capability is required for all variations of the trickling filter process except roughing filters provided that minimum hydraulic loading rates are maintained at all times.
What are the different types of trickling filter?
Types of trickling filters in wastewater treatment
- Intermittent sand filters.
- Contact beds.
- Low rate trickling filters.
- High rate trickling filters.
What is the typical cause of pounding on a trickling filter?
A condition occurring on trickling filters when the hollow spaces (voids) become plugged to the extent that water passage through the filter is inadequate. Ponding may be the result of excessive slime growths, trash, or media breakdown.
What is trickling filter with diagram?
Trickling filters (TFs) are used to remove organic matter from wastewater. The TF is an aerobic treatment system that utilizes microorganisms attached to a medium to remove organic matter from wastewater.
What is the depth of trickling filter?
The trickling filter is a nonsubmerged fixed film biological reactor using rock or plastic support media. The depth of the support media ranges from 0.9 to 2.5 m and averages 1.8 m. Filter beds are usually circular and the liquid wastewater is distributed over the top of the bed by a rotary distributor.
How do you calculate the efficiency of a trickling filter?
Overall Efficiency of Two Stage Trickling Filter is the total efficiency obtained after the waste passes from 2 filters and is represented as E = (Qi-Qo/Qi)*100 or Overall efficiency TF = (Influent BOD-Effluent BOD/Influent BOD)*100.
What are the components of a trickling filter?
A trickling filter is a type of wastewater treatment system. It consists of a fixed bed of rocks, coke, gravel, slag, polyurethane foam, sphagnum peat moss, ceramic, or plastic media over which sewage or other wastewater flows downward and causes a layer of microbial slime (biofilm) to grow, covering the bed of media.
What are the remedial measures for ponding nuisance?
Due to ponding nuisance the sewage cannot pass through the filter and the treatment work is stopped. ADVERTISEMENTS: The ponding nuisance can be prevented and removed by the following methods: (i) By drying the filter media for 15 to 48 hours by exposing it to the sun and loosening the aggregate with steel bars.
Why lime is used in water treatment?
Lime softening is a water treatment process that uses calcium hydroxide, or limewater, to soften water by removing calcium and magnesium ions. In this process, hydrated lime is added to the water to raise its pH level and precipitate the ions that cause hardness.
What is slime layer in trickling filter?
What is the recirculation ratio for a trickling filter?
0.5:1 to 4:1
9 Explain why a trickling filter or RBC may be intentionally shock loaded with chlorine. Recirculation ratios are expressed as the volume of return recirculation flows to the volume of the influent wastewater. Recirculation ratios generally run from 0.5:1 to 4:1.
What is NRC formula?
For a single stage or first stage rock trickling filter, the NRC equation is. where W = BOD loading to the filter, lb/d (kg/d) V = Volume of the filter media, 10 ft (m ) F = Recirculation factor. 2a.
How do I stop ponding water?
Think of a low slope roof as positive drainage in action. The area at the top is higher, allowing gravity to pull water into rain gutters. When used on a large rubber roof, positive drainage systems effectively turn sections of the roof into a slight low slope in order to avoid ponding that may happen in problem areas.
What is pH adjustment in water treatment?
What is a pH Adjuster for Water Treatment? A pH adjuster is a chemical used to alter the pH or Potential Hydrogen level. pH (Potential Hydrogen) is the measurement of the activity of the hydrogen ion or how basic or acidic something is. By adding a pH reagent such as an acid you can drive pH downward.
How ponding can be eliminated in trickling filter?
Minor Ponding : can be eliminated by : – Spraying the surface with high pressure water hose. – Stirring or agitating ponding area with stick, rake, etc. – Dousing the filter with chlorine.
What is oxidation ditch?
An oxidation ditch is a modified activated sludge biological treatment process that utilizes long solids retention times (SRTs) to remove biodegradable organics. Oxidation ditches are typically complete mix systems, but they can be modified to approach plug flow conditions.
What is an organic roughing filter?
Roughing Filters: A classification of trickling filters in which the organic is in excess of 200 lb of BOD5per 1,000 cubic feet of media per day. A roughing filter is used to reduce the loading on other biological treatment processes to produce an industrial discharge that can be safely treated in a municipal treatment facility.
What is a trickling filter design example?
Trickling Filter Design Trickling Filter Design NRC Design Example Design a two-stage trickling filter system to treat a wastewater flow\rof 2 MGD with a strength of 400 mg/L BOD5. Each filter is to\rbe 8 ft. deep and operated at a recirculation ratio of 4:1. A 90% BOD5removal is desired. Solution:\r\r
What are the characteristics of a roughing filter?
Roughing filter: Hydraulic loading (gpd/ft3) of >900, continuous sloughing frequency, recirculation not normally included, typically 40 to 65% removal rate, 40 to 65% TSS removal rate. Trickling Filter Equipment Distribution systems evenly spread wastewater over the entire media surface.
What is a standard rate trickling filter?
Standard rate trickling filters are normally designed for hydraulic ratings of 1.1 to 4.3 m3/m2/d and organic loadings of 0.08 to 0.41 kg BOD/m3/d. These filters are normally 1.8 to 2.4 m deep and rectangular or circular in shape. They are usually dosed intermittently by dosing tanks with automatic siphons or by periodic pumping.