Diclofenac Toxicity Abatement in Wastewater with Solar Disinfection: A Study in the Rural Area of Brazil’s Central−West Region

Abstract

Domestic wastewater has been targeted for the presence of emerging contaminants such as antibiotics, of which diclofenac is one of the most frequently detected. Many studies have focused on the removal of these emerging pollutants. However, the legislation has focused on toxicity monitoring. In search of simplified solutions for rural areas, and to guarantee the safe reuse of effluent in agriculture, this study evaluated the efficiency of a decentralized solar disinfection (SODIS) system regarding the reduction of ecotoxicity, phytotoxicity, and pathogens in domestic wastewater after adding diclofenac potassium. For this purpose, the bioindicators Artemia sp., Allium cepa L. and Lactuca sativa were used, after 1, 2, and 3 h of exposure to solar radiation. After 3 h of exposure to solar radiation, toxicity was reduced and root growth inhibition was noted, which indicates low effluent toxicity after treatment by the SODIS system. It was achieved a reduction of 3 and 2 log units in the concentration of total coliforms and Escherichia coli, respectively.