An ATP luminescence method for direct toxicity assessment of pollutants impacting on the activated sewage sludge process

An ATP luminescence method was used to determine the toxicity of three reference toxicants to two sources of domestic activated sludge, and an activated sludge from a laboratory model plant. Repeatability in the ATP test was demonstrated for Cr (as K2Cr2O7), Zn (as ZnSO4.7H2O), and 3,5-dichlorophenol (3,5-DCP) using each source of activated sludge. The three sources of sludge showed sensitivity to Cr and 3,5-DCP, and insensitivity to Zn using the ATP luminescence method. Sludge source did not appear to effect test response. The toxic response to 3,5-DCP in model and domestic activated sludge was shown to be dependent on sludge solid concentration (measured as total suspended solids, g TSS l−1). It is recommended that a standard solids concentration is used during toxicity evaluation.