Pharmaceutical compounds in anaerobic digestion: a review on the removals and effect to the process performance

Abstract

Anaerobic digestion has been studied as a potential enhancement to the existing conventional treatment processes in removing pharmaceutical compounds from wastewater streams. The removals of pharmaceuticals were achieved through biotransformation and sorption to solids. There are instances where complete removal could not be achieved and the compounds remained as residuals in the treated effluent. Among the factors influencing the removals include the chemical structure of the compounds, biological condition, acclimatisation, operational pH, sludge characteristics, adsorption, hydraulic retention time and temperature. Pharmaceutical compounds also displayed strong influence for methane gas production, utilisation of substrates for methane conversion and shifting of microbial diversity during the treatment process. This review covers recent findings on the key information of pharmaceutical compound removal and the effect of their presence on the anaerobic treatment process.