These small volumes of wastewater are not always adequately treated because of low financial, technical and/or managerial capacity or treatment plants that are out of commission or overloaded and thus discharge into the environment (rivers, lakes, sea, etc.) effluents that may contaminate food and downstream water supplies, creating public health risks, environmental damage, and unpleasant living conditions. As the volumes of untreated wastewater are continuously increasing, the pollution of water bodies tapped for irrigation is worsening. The rapid and unplanned growth of cities continues to outpace improvements in sanitation and wastewater infrastructure, making the management of urban wastewater more complex and ineffective. The prospects regarding the increase in wastewater treatment capacity in these cities are gloomy.