ABSTRACT
In many countries, urban effl uents are subjected to physiochemical and biological treatments. Anaerobic digestion continues to be the most widely used wastewater management process because it represents a sustainable system and an suitable method for developing countries. This chapter presents an evaluation of the up fl ow anaerobic sludge reactor (UASB) operation, its advantages, and use in water and environment conservation. The technique combines physical, and biological processes with anaerobic degradation such as hydrolysis, fermentation, acetogenesis and methanogenesis. Formation of granules is key step for the success of the UASB. Various groups of bacteria dominate the metabolic pathways in the granules and the wastewater decomposition. The advantages of the reactor are: conservation of the environment, low energy consumption, and biogas and low sludge production. Temperature, pH, fl ow rate, infl uent type and concentration, sludge retention time, nutrient availability and presence of xenobiotics may be limitations. The fi rst section describes the role of anaerobic wastewater treatment, as a biological process, while the second explains its application and performance in domestic and industrial wastewater treatment. The third section presents advantages and disadvantages of the UASB reactor and assesses the effects of physical parameters on the operational process. The fi nal part is devoted to studying the management of aquatic ecological risks.
