Role of hydrophilic organic matter on developing toxicity in decay process of activated sludge

• Published in: Water Science & Technology Vol. 52; no. 8; pp. 63 - 70
• Main Authors: NARITA, H, FUNAMIZU, N, TAKAKUWA, T, KUNIMOTO, M
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Oxford Pergamon 01-01-2005; IWA Publishing
• Subjects: Activated sludge; Activated sludge process; Air. Soil. Water. Waste. Feeding; Anion Exchange Resins; Applied sciences; Bacteria; Bio-assays; Bioassays; Biological and medical sciences; Biological Assay; Carbon - metabolism; Cell Line; Cell lines; Decay; Dose-Response Relationship, Drug; Environment. Living conditions; Exact sciences and technology; Humans; Influents; Medical sciences; Organic matter; Oxygen - metabolism; Pollution; Public health. Hygiene; Public health. Hygiene-occupational medicine; Sewage - chemistry; Sewage - microbiology; Sludge; Time Factors; Total organic carbon; Toxicity; Viability; Waste Disposal, Fluid; Water Pollutants, Chemical - toxicity; Water treatment and pollution; Water treatment plants
• ISBN: 184339555X; 9781843395553
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2005.0227

It is known that the toxicity of effluent is more intensive than that of influent in the activated sludge process. In this study, we applied bioassay using cultured human cell lines to the decay process of activated sludge to evaluate the toxicity of organic matter generated and/or released from activated sludge bacteria. We also applied this bioassay to hydrophilic fraction of samples. The bioassay results showed that: (1) the variation in the dose-response relation obtained from assay with original samples was observed during decay; (2) on the other hand, the response curves of only hydrophilic fraction at each time show the same relationship between TOC and viability of MCF7 cells; (3) this trend was confirmed by plotting the time course of EC50. These results imply that: (1) the hydrophilic organic matter controlled for developing toxicity during decay process of activated sludge; and (2) the character of hydrophilic organic matter is not changed during the experimental period.