Review of sanitation with a single-treatment approach of septic wastewater produced in decentralised areas

Abstract The proper management of septic wastewater in rural and peri-urban areas is vital for ensuring both environmental sustainability and public health. This review examines the composition of septic wastewater and the challenges associated with treatment through a single-treatment approach, evaluating different processes, and providing a comparative analysis to guide their selection. Different technologies have been investigated in the literature, namely sequencing batch reactors with floccular or granular sludge, membrane bioreactors in aerobic or anaerobic conditions, and up-flow anaerobic sludge blanket reactors, focusing on their mechanisms, operational efficiencies, and applicability. This paper highlights advantages, limitations, and design considerations for each technology, emphasizing their suitability for different wastewater compositions and flow rates. The results highlight that sequencing batch reactors are ideal for direct decentralised applications due to their flexibility and versatility, while membrane bioreactors and up-flow anaerobic sludge blanket reactors can be seen as an upgrade of wastewater treatment plants that have reached the full capacity, to allow the treatment of additional septic wastewater brought from decentralised areas. This review provides a valuable resource for researchers and engineers seeking sustainable solutions for decentralised wastewater treatment.