Assessment and spatial mapping of treated wastewater quality for safe agricultural reuse in Tunisia

ABSTRACT Treated wastewater (TWW) reuse in agriculture offers a solution to water shortage, enhances crop production, and supports environmental sustainability. This study assessed TWW quality across Tunisia. Surveys and analyses of seven physicochemical (total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand over five days (BOD5), cadmium, and lead) and five microbiological (faecal coliforms, faecal streptococci, Salmonella spp., Vibrio cholerae, and helminths eggs) parameters were conducted on 81 samples from 27 wastewater treatment plants (WWTPs) (2017–2018). Compliance with standards was found in 11.11% (COD), 14.80% (BOD5), and 18.50% (TSS) of WWTPs. Cadmium, lead, and V. cholerae were fully removed. However, faecal indicators did not meet standards. Maps and multiple correspondence analysis confirmed a need for better treatment and tertiary processes to eliminate microbiological contamination.