Biological sludge

The microorganisms grow in response to the food source suppHed in the wastewater and produce more biological sludge than is needed to maintain the process. This excess sludge must be wasted from the process and is usually treated by dewatering and aerobic or anaerobic digestion. 

Biological sludges can be iacorporated iato the sod. An important consideration is the heavy metal content of the sludge, which will dictate the total number of years sludge can be appHed. The avadable nitrogen content of the sludge will determine the maximum yearly appHcation. 

Seeding Introduction of microorganisms (such as ALKEN CLEAR-FLO 1000 series for aquaculture, 4000 series for grease, and 7000 series for industrial and municipal wastewater) into a biological oxidation unit to minimize the time required to build a biological sludge. Also referred to as inoculation with cultured organisms. 

The activated sludge process usually must be preceded by neutralization and some metal removal, and possibly by solids removal. The process is normally followed up by a separation step, usually sedimentation, to remove the biological sludge from the waste liquid stream. 

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. 

In the conventional activated sludge process with biological sludge recycled from the final sedimentation clarifier, shown in Figure 27.11, the mean cell residence time or sludge retention time is... 

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. 

Triclosan is an antimicrobial compound widely used in household products, including cosmetics, oral sanitary products, detergents, etc. Thence, it is not surprising that it was detected in concentrations of approximately 1,000 ng/g in treated sludge and 5,000 ng/g in biological sludge from an urban WWTP in Spain [48],... 

Biological sludge, 25 912, 914 Biological specimen freezing, nitrogen in, 77 287... 

Incineration of mycelium and excess biological sludge. Incineration system may also receive pathogenic wastes, unrecoverable solvents, fermentation broths or syrups, semi-solid and solid wastes, and so on. The system can be further integrated with the burning of odorous air streams. 

A stabilization pond is a simple pond in which aeration is not mechanically enhanced. Its shallow depth allows the pond to function aerobically without mechanical aerators. Algae in the pond produce oxygen through photosynthesis, which is then used by the bacteria to oxidize the wastes. Because of the low loadings, little biological sludge is produced and the pond is fairly resistant to upsets due to shock loadings. 

One paper mill, Inland-Rome, in Rome, GA, ran four tests burning varying amounts of wood waste, TDF, biological sludge from the plants secondary effluent treatment system, and coal.2 One TDF test was run at 7 percent TDF and 93 percent wood waste particulate emissions were similar to baseline.2 Another test was run with 12.8 percent TDF, 12.1... 

A positive result of TDF use in waste wood boilers is that facilities are able to bum sludge and waste wood more successfully, decreasing the likelihood of solid waste disposal problems. Results from a series of waste wood boiler performance tests using ASMS codes concluded that use of TDF supplementally in hog-fuel boilers enhances combustion of wood waste, and enables disposal of biological sludge in conjunction with wood waste without necessitating use of other fossil fuels such as coal.2 No applicable environmental limits were exceeded during these tests.2... 

Chemical pretreatment of biological sludge using acid, base, or enzyme may enhance the sonication effect. Such chemicals weaken the cell wall, effectively disrupting the biological cells with less energy input. Bases such as NaOH and KOH are widely... 

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