Compact WWTPs as a decentralized wastewater treatment system in isolated or small communities

Decentralized wastewater treatment plants represent an alternative to enhance public access to sanitation and, consequently, their health standards. Compact wastewater treatment plants (WWTPs) are easier to operate than the complex systems used in centralized wastewater treatment facilities. Therefore, they prove to be well-suited for isolated communities or small cities, particularly in regions like the Global South. However, various technologies are available for application in these areas. To assist in decision-making, we evaluated 6 full-scale compact WWTPs based on 21 indicators encompassing implementation factors (storage of chemical products, land occupation by treatment, index of moving parts, etc.), operational aspects (odour complaints, energy consumption, sludge production, etc.), environmental regulations, and enhancement of the receiving water body (nitrogen removal efficiency, phosphorus removal efficiency, etc.). Following the analysis, the prolonged aeration activated sludge setup emerged as a standout choice due to its potential for application in remote areas or small communities.