Biological sludges treatment

Biological wastewater treatment processes also affect solids characteristics and hence solids separation. Activated sludge solids have been found to have a distinct bimodal distribution with one mode in the supracolloidal to settleable range and another near the border between the colloidal and supracolloidal fractions. The concentrations and size limits in each range are affected by conditions in the... 

Centrifugation is a well-established liquid-solid separation process popular in commercial and municipal waste treatment facilities. It is usually used to reduce slurry and sludge volumes and to increase the solids concentration in these waste streams. It is a technically and economically competitive process and is commonly used on waste sludges produced from water pollution control systems and on biological sludges produced in industry and municipal treatment facilities. 

Industrial treatment plants may not be able to use their biological sludges as fertilizer or spread them on nearby fields if certain substances are present. They may be forced to dry and bum them instead. In some cases, as when heavy metals are present, they may have no recourse but to recover them or use deep-well or ocean-dumping methods. Often anaerobic digestors are used to reduce the amount of sludge and hence the size of subsequent equipment or the cost of ultimate disposal. 

Tower Biology A biological waste-treatment process, developed from the Activated Sludge process. The sludge is contained in a tall tower, at the base of which oxygen is injected as small bubbles. The bubbles are almost completely absorbed by the time they reach the surface of the liquid. The system uses less energy than does surface aeration. Developed by Bayer in 1980 for its plant at Leverkusen, Germany subsequently adopted in India and then elsewhere. 

Microbial processes in terms of sludge (biomass) production, BOD and nutrient removal have been focused on when dealing with biological wastewater treatment. Therefore, and because the sewer is the system for input to the wastewater treatment plant, there is a basis as well as a perspective to establish a process concept for the sewer that can be integrated with the activated sludge processes. 

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