Energy self-sufficiency in wastewater treatment plants: perspectives, challenges, and opportunities

Energy demand of wastewater treatment plants (WWTPs) is counted as an important energy consumer especially in developed and developing countries. Environmental concerns and pressure on freshwater resources have caused to implement energy-intensive wastewater treatment processes and thus highly energy demanding WWTPs. Although wastewater itself holds a substantial amount of chemical and thermal energy, conventional management practices are not capable of recovery this energy content. Since there has been a paradigm shift in wastewater treatment, wastewater is considered as an important energy source. Several new applications have been developed to recover energy content of wastewater as much as possible. The recent developments in materials and equipment also promise a significant opportunity to improve energy balance of WWTPs. Adopting new measures and enhancing energy recovery show that WWTPs do not have to be energy consumers no longer, instead they can be energy-neutral and even energy-positive systems.