Possible impacts of exogenous pollutants occurring in waste activated sludge during anaerobic digestion
Keywords:Activated sludge, anaerobic digestion, pharmaceutical products, persistent organic pollutants, heavy metals
Anaerobic digestion is considered as a biological procedure as the metabolisms included in the digestion process of waste activated sludge are easily affected by distinct operating conditions. This study investgates the impact of regularly distinguishable pollutants with high concentrations in waste activated sludge such as nanoparticles, pharmaceutical products and heavy metals on the execution of waste activated sludge digestion. Different types of exogenous pollutants showed different effects on the sludge methanogenesis and acidification processes, hydrolysis and solubilization as well as the correlating concentrations. It was also observed that the majority of the pollutants observed in the waste activated sludge would normally react towards anaerobic digestion at low levels but exhibit obvious negative impacts at high dosages.