Low temperature anaerobic biotreatment of priority pollutants

The effect of low operating temperature and pollutant concentration on the performance of five anaerobic hybrid reactors was investigated. Stable and efficient long-term (>400 days) treatment of a cold (6–13°C), volatile fatty acid (VFA)-based, wastewater was achieved at applied organic loading rates (OLRs) of 5 kg chemical oxygen demand (COD) m⁻³ d⁻¹ with COD removal efficiencies c. 84% at 6°C (sludge loading rate (SLR) 1.04–1.46 kg COD kg [VSS]⁻¹ d⁻¹). VFA-based wastewaters, containing up to 14 g pentachlorophenol (PCP) m⁻³ d⁻¹ or 155 g toluene m⁻³ d⁻¹ were successfully treated at applied OLRs of 5–7 kg COD m⁻³ d⁻¹. Despite transient declines in reactor performance in response to increasing toxicant loading rates, stable operation (COD removal efficiencies > 90%) and satisfactory toxicant removal efficiencies (>88%) were demonstrated by the systems.