Waste stabilization ponds are ponds designed and built for wastewater treatment to reduce the Waste stabilization ponds are used worldwide for wastewater treatment and are especially ... The system may consist of a single pond or several ponds in a series, each pond playing a different role in the removal of pollutants.Waste stabilization ponds involve natural treatment processes which take time because removal rates are slow. Environmental factors like sun radiation, wind, biological processes, and hydrodynamics have been analyzed. High rate algal ponds are specially designed waste stabilization ponds in which the algal population is gently stirred mechanically, usually in some form of race-track configuration to optimize algal production. The mechanisms of faecal coliform removal are not surprisingly, multifactorial. However, the factors can be divided into fast and slow. Faecal coliforms are the organisms most commonly used to monitor the removal of pathogens from wastewater treatment plants. This indicator has been compared with other indicators and salmonellae. Therefore, larger areas are required than for other treatment processes with external energy inputs. Waste stabilization ponds described here use no aerators. High-performance lagoon technology that does use aerators has much more in common with the activated sludge process. Waste stabilization ponds are used worldwide for wastewater treatment and are especially suitable for developing countries that have warm climates. They are frequently used to treat sewage and industrial effluents, but may also be used for treatment of municipal run-off or storm water. The reactions take place by the joint participation of several microorganisms living within the pond. The organic matter is measured as biochemical oxygen demand (BOD). BOD values in the pond effluent are lower than in the influent, reflecting the removal of organic matter. This pond biome uses organic matter from the wastewater as food. There are three types of ponds, (1) anaerobic, (2) facultative and (3) aerobic (maturation), each with different treatment and design characteristics. The anaerobic pond is transferred to the facultative pond, where further BOD is removed. The top layer of the pond receives oxygen from natural diffusion, wind mixing and algae-driven photosynthesis. The lower layer is deprived of oxygen and becomes anoxic or anaerobic. Settle able solids accumulate and are digested on the bottom of the pond. The aerobic and anaerobic organisms work together to achieve BOD reductions of up to 75%.The UV portion of sunlight directly damages pathogen genomes (photobiological damage), while UV and visible wavelengths can react with photosensitizers in WSPs (such as natural organic matter) or photosensitizer molecules within bacteria (such as NADH/NADPH, flavins and porphyrins) to produce reactive species that indirectly damage pathogens (photo-oxidative damage). Sunlight is stronger at lower latitudes, higher elevations, and in locations with less cloud cover.The most important physical-chemical factors for pathogen inactivation are pH, temperature and dissolved oxygen in the presence of dissolved organic matter. Most bacterial pathogens are vulnerable to high pH, with Vibrio spp. as a notable exception. The sanitizing effect of free ammonia, which becomes more available at higher pH, is even more effective at higher temperatures. Nevertheless, there are several design approaches that can help enhance pathogen removal in WSP systems.
@Susmita One very important condition for Waste Stabilization Pond (WSP) usage is the climatic condition. It's efficiency depends on the availability of sunlight and high ambient temperatures.
Also, the influent load of the wastewater, method of oxygenation and perhaps the type of wastewater are important considerations for WSP usage.
The flow rate into the pond must be carefully considered along side the pond design criteria including the desired efficiency (which is to some extent dependent on the detention time, the influent load and the complex kinetics of substrate removal and bacteria dieoff). There may be need to construct several WSPs in order to meet the design wastewater discharge of load centres under consideration and also to improve the efficiency of treatment.
Please note that the conventional WSPs usually require large land area. You may wish to refer to advances made in respect of the improvement of the conventional WSPs.
Can WSPs alone be used for primary, secondary and tertiary wastewater treatment? Is it possible to produce biogas and digestate from WSPs as standalone plants? If yes, what features must be designed into such systems or the retrofits of traditional waste lagoons or ponds without AD capability?