Sustainable technologies for on-site domestic wastewater treatment: a review with technical approach

The rapid population growth has rendered the centralized sewerage systems a non-realistic option in sparsely populated areas, particularly in developing countries. In this context, on-site domestic wastewater treatment system (ODWTS) has proved to be a viable and prefered alternative for the management of domestic wastewater in such areas. Among various treatment systems available, the conventional septic tank is the oldest and the most widely utilized on-site treatment system. However, its sustainability is still questionable due to its inability to meet the strict discharge requirements. Such limitations have already given enough impetus to explore subsequent post-treatment or polishing technologies to achieve the desired effluent disposal or reuse standards. In order to improve the quality of the treated domestic wastewater, various ecologically safer and economically viable technological options have been implemented successfully. The present study summarizes various on-site domestic wastewater treatment technologies which have been successfully implemented under actual field conditions with special reference to the system's performance (individual and comparative) as well as techno-economic analysis. Further, various sustainability indicators of ODWTS, such as environmental, social, and economic viability for the selection of on-site treatment technologies, are also reviewed in this study.