Wastewater biological

WEF (1994), Wastewater biology The life processes, a special publication prepared by Task Force on Wastewater Biology The Life Processes, chaired by M. H. Gerardi, Water Environment Federation (WEF), p. 184. 

WUbams, C. J. and R. G. J. Edyvean (1998). Investigation of the biological foubng in the filtration of seawater. Water Science and Technology, Wastewater Biological Processes, Proc. 1998 19th Biennial Conf. Int. Assoc, on Water Quality. Part 7, Jnne 21-26, Vanconver, BC, 38, 8-9, 309-316. Elsevier Science Ltd., Exeter, England. 

IV TWW alone Wastewater biologically treated on long-term activation and aerobic stabilization of the sludge contains substantially higher amormts of pollutants than II and III reddish brown in colour with slight opalecence... 

Figure 4.12. Comparison between aerobic and anaerobic wastewater biological treatment, a wastewater, b biomass content, c hydraulic retention time.

Treybal, R. E. 1987. Mass-Transfer Operations, 3d ed. (reprint), McGraw-HUl, New York. Viraraghaven, T., and S. R. Kikkeri. 1988. Peat Filtration of Food-Processing Wastewaters, Biological... 

Regina Maria de Oliveira Barros Nogueira (water and wastewater biology). Institute for Sanitary Engineering and Waste Management, Leibnitz University Hannover,... 

Even when not specifically designed for the removal of heavy metals, most waste-treatment processes remove appreciable quantities of the more troublesome heavy metals encountered in wastewater. Biological waste treatment effectively removes metals from water. These metals accumulate in the sludge from biological treatment, so sludge disposal must be given careful consideration. 

Primary or pretreatment of wastewater prior to biological treatment involves both physical and chemical treatment depending on the nature of the emission. 

The capital cost of most aqueous waste treatment operations is proportional to the total flow of wastewater, and the operating cost increases with decreasing concentration for a given mass of contaminant to be removed. Thus, if two streams require different treatment operations, it makes no sense to mix them and treat both streams in both treatment operations. This will increase both capital and operating costs. Rather, the streams should be segregated and treated separately in a distributed effluent treatment system. Indeed, effective primary treatment might mean that some streams do not need biological treatment at all. 

Z. Evaporation. If the wastewater is in low volume and the waste material involatile, then evaporation can be used to concentrate the waste. The relatively pure evaporated water might still require biological treatment after condensation. The concentrated waste can then be recycled or sent for further treatment or disposal. The cost of such operations can be prohibitively expensive unless the heat available in the evaporated water can be recovered. 

Another important example of redox titrimetry that finds applications in both public health and environmental analyses is the determination of dissolved oxygen. In natural waters the level of dissolved O2 is important for two reasons it is the most readily available oxidant for the biological oxidation of inorganic and organic pollutants and it is necessary for the support of aquatic life. In wastewater treatment plants, the control of dissolved O2 is essential for the aerobic oxidation of waste materials. If the level of dissolved O2 falls below a critical value, aerobic bacteria are replaced by anaerobic bacteria, and the oxidation of organic waste produces undesirable gases such as CH4 and H2S. 

AH other organic waste-process and vent streams are burned in a dare, in an incinerator, or in a furnace where fuel value is recovered. Wastewater streams are handled in the plant biological treatment area. 

The wastewater produced in this process consists mostly of water used in cleanup and propellant conveyance and sorting operations. Techniques such as the use of activated carbon and biological treatment are being investigated for the removal of solvents and dissolved organic compounds (143). 

Wastewater. Phenol is a toxic poUutant to the waterways and has an acute toxicity (- 5 m g/L) to fish. Chlorination of water gives chlorophenols, which impart objectionable odor and taste at 0.01 mg/L. Biochemical degradation is most frequently used to treat wastewater containing phenol. Primary activated sludge, along with secondary biological treatment, reduces phenol content to below 0.1 mg/L (69). 

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