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Conventional wastewater treatment technologies improve the quality of wastewater discharged into the environment and restrain polluted waters from contaminating other available clean water resources. This section focuses on wastewater treatment and advancing technologies for newer designs. Treatment of wastewater follows three stages, primary, secondary, and tertiary. After wet well, wastewater is treated in a pretreatment phase for removal of debris and larger particles, followed by primary treatment involving various types of screen and settlers. The secondary treatment of wastewater includes biological treatment (in aerobic and/or anaerobic phases). The aerobic phase comprises activated sludge, trickling filters, etc. However, the practice of combinatorial (aerobic and anaerobic) phase may lead to better development and efficient removal of effluents in the future. Secondary treatment may also be categorized based on chemical and biological processes. Our focus here has been on the biological mode which is less-expensive, efficient and environmental friendly. Finally, the tertiary stage is for further removal of pathogens, toxins, nutrients, etc. A considerable amount of construction of new treatment plants and upgrading of the treatment facilities are expected in the near future. There is still many opportunities to improve treatment plant design methodology to produce least cost designs. |
