Untreated domestic sewage causes severe ecological harm by polluting both ground and surface water, and it is thus important to dispose of it safely (Elango et al., 2007). This leads to a need for wastewater treatment plants (WWTPs). The best technique for treating sewage varies with the characteristics of cities, such as climate, topography, wastewater pollution, land prices, and other factors (Nuvolari, 2003). Activated sludge systems and anaerobic reactors are among the methods most used for domestic sewage treatment. The technologies used for sewage treatment in Brazil are listed in Table 1, where a predominance of anaerobic treatment can be seen.