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The increase in population and urbanization have resulted in an increase in the number of wastewater treatment plants in South Africa. Although wastewater treatment plants serve a great purpose in the reduction of environmentally threatening contaminants from wastewater, the increase in energy consumption by these plants raises concerns about climate change. Thus, there has been a rise in literature attempting to map the energy consumption of wastewater treatment plants to help decision-making in the search for alternative energy sources to promote self-sufficient wastewater treatment plants. There has been a proposition of capturing energy from sewers to mitigate the greenhouse gas emanating from energy consumption by wastewater treatment plants. Literature has proven that sewers can produce 10 times the energy required to operate wastewater treatment plants with the correct factors considered including the characteristics of the wastewater being treated, the technology used, and the management practices employed. This has resulted in a rise in the number of studies investigating biogas production from wastewater treatment plants. Although sewage has been proven to be able to produce sufficient biogas to support the energy requirements of wastewater treatment plants to go off-grid. There are still challenges in the implementation of self-sufficient wastewater treatment plants especially in developing countries such as technological barriers and capital investments. Therefore, this paper will investigate possible ways of making wastewater treatment plants more energy sustainable. Out of many approaches of making WWTP sustainable (resource recovery and energy efficiency improvements); energy generation is the main focus of this mini review. [ABSTRACT FROM AUTHOR]

Sugar industry is one the biggest contributors to the environmental pollution in the modern world. The effects are specifically felt by the aquatic environment which in turn affects the human beings as they depend (partially and otherwise) on the aquatic creatures such as fish for food resource. Also, water demands are growing continually as human population increases although the supply of water is diminishing. The disposal of the effluent from industries to water streams becomes detrimental as it does not only disturb the aquatic life but also the water quality that is used for domestic and agricultural purposes. Effluent discharging industries include thermal power plants, paper mills, oil refineries, sugar mills etc. The composition of this effluent is total suspended solids, chemical oxygen demand, biological oxygen demand, heavy metals and sometimes the total dissolved solids. Treatment and reuse of industrial effluent (wastewater) then becomes a necessary step to meeting the environmental strain. One way of effectively solving the crisis of industrial wastewater is through treating while making additional useful products such as biogas and electricity. The aim of the present paper is to do a thorough analysis of the effluent from sugar milling industry for production of biogas and electricity through anaerobic digestion. [ABSTRACT FROM AUTHOR]