Aerobic water treatment

It has long been known that, under appropriate conditions and especially in the liquid phase, synergistic associations can develop between microbiological systems and activated carbons or other support media (e.g.. in trickling bed filters for aerobic water treatment). In liquid phase applications, bacterial colonization of activated carbon can occur quite readily [76-79]. For example, the adsorptive capacities of activated carbon beds used in water treatment are often greatly enhanced by the presence of microorganisms, and the useful filter life is extended beyond that expected for a process of purely physical adsorption. Essentially, the... 

To be accessible to the waste-consuming bacteria the oxygen must be dissolved in the water. One of the limiting factors in aerobic water treatment is the rate of oxygen transfer from the air to the contaminated water. The rate of transfer is determined by the surface area of water in contact with the air and the partial pressure of the oxygen. 

Silicones are ecologically inert, having no effect on aerobic or anaerobic bacteria. Thus they do not inhibit the biological processes taking place during waste water treatment. 

The most widespread biological application of three-phase fluidization at a commercial scale is in wastewater treatment. Several large scale applications exist for fermentation processes, as well, and, recently, applications in cell culture have been developed. Each of these areas have particular features that make three-phase fluidization particularly well-suited for them Wastewater Treatment. As can be seen in Tables 14a to 14d, numerous examples of the application of three-phase fluidization to waste-water treatment exist. Laboratory studies in the 1970 s were followed by large scale commercial units in the early 1980 s, with aerobic applications preceding anaerobic systems (Heijnen et al., 1989). The technique is well accepted as a viable tool for wastewater treatment for municipal sewage, food process waste streams, and other industrial effluents. Though pure cultures known to degrade a particular waste component are occasionally used (Sreekrishnan et al., 1991 Austermann-Haun et al., 1994 Lazarova et al., 1994), most applications use a mixed culture enriched from a similar waste stream or treatment facility or no inoculation at all (Sanz and Fdez-Polanco, 1990). 

Baird, R., Carmona, L., and Jenkins, R.L. Behavior of benzidine and other aromatic amines in aerobic wastewater treatment, J. Water Pollut. Control Fed, A9(1) IG09-1615, 1977. 

Lee, E.G.-H. Crowe, M.F. Stutz, H. Anaerobic-aerobic lagoon treatment of Kraft mill effluent for enhanced removal of AOX. Water Pollut. Res. J. Can. 1993, 28, 549-569. 

Eliminates the need for surface water treatment may eliminate the need for surface vapor treatment for aerobically biodegradable contaminants in permeable soils. 

Aerobic biological treatment process for domestic or industrial wastewaters. Treated water from this process can often be used as a low cost makeup water source for cooling towers. 

At NSF, a great deal of work is done on the development and implementation of NSF standards and criteria for health-related equipment. The majority of NSF standards relate to water treatment and purification equipment, products for swimming pool applications, plastic pipe for potable water as well as drain, waste, and vent (DWV) uses, plumbing components for mobil homes and recreational vehicles, laboratory furniture, hospital cabinets, polyethylene refuse bags and containers, aerobic waste treatment plants, and other products related to environmental quality. 

DEHP is a widely used chemical that enters the environment predominantly through disposal of industrial and municipal wastes in landfills and, to a much lesser extent, volatilization into air (from industrial and end uses of DEHP), carried in waste water from industrial sources of DEHP, and within effluent from municipal waste water treatment plants. It tends to sorb strongly to soils and sediments and to bioconcentrate in aquatic organisms. Biodegradation is expected to occur under aerobic conditions. Sorption, bioaccumulation, and biodegradation are likely to be competing processes, with the dominant fate being determined by local environmental conditions. When DEHP is present in the environment, it is usually at very low levels. It is very difficult to determine these low levels accurately since DEHP is a ubiquitous laboratory contaminant, and laboratory contamination may cause false positives to be reported in the literature. 

Beltran-Heredia J, Torregrossa J, Garcia J, Dominguez JR, Tiemo JC. Degradation of olive mill wastewater by the combination of Fenton s reagent and ozonation processes with an aerobic biological treatment. Water Sci Technol 2001 44 103-108. 

Gas/liquid contacting is frequently encountered in chemical reaction and bioprocess engineering. For reactions in gas/liquid systems (oxidation, hydrogenation, chlorination, and so on) and aerobic fermentation processes (including biological waste water treatment), the gaseous reaction partner must first be dissolved in the liquid. In order to increase its absorption rate, the gas must be dispersed into fine bubbles in the liquid. A fast rotating stirrer (e.g. a turbine stirrer), to which the gas is supplied from below, is normally used for this purpose (see the sketch in Fig. 34). 

For best performance aerobic biological waste water treatment plants must be maintained at a constant dissolved oxygen (DO) level. Under certain conditions, e.g. adverse weather conditions or under biological oxygen demand (BOD) overloaded conditions, DO levels drop and treatment effectiveness can be seriously reduced. Continuous running under lower than optimum DO levels leads to biological upsets such as proliferation of anaerobic or filimentous... 

Manganese occurs in groundwaters and surface waters that are low in oxygen it often occurs with iron. When it is oxidized in aerobic waters, manganese precipitates as a black slimy deposit, which can build up in distribution to cause severe discolouration at concentrations above about 0.05 mg/L, The health-based guideline value is 0,4 mg/L, Monitoring is only likely to be required for operational reasons where a potential problem has been identified, in which case, final water from the treatment works would normally be the most appropriate sample site. 

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