Low-temperature inhibition of the activated sludge process by an industrial discharge containing the azo dye acid black 1

• Published in: Water research (Oxford) Vol. 39; no. 1; pp. 17 - 28
• Main Authors: Martin, Ronald W., Robert Baillod, C., Mihelcic, James R.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2005; Elsevier Science
• Subjects: Activated sludge; Amido Black; Ammonia - metabolism; Applied sciences; Azo dye; Bacteria - metabolism; Biological and medical sciences; Biological treatment of waters; Bioreactors; Biotechnology; Coloring Agents; Environment and pollution; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Industrial applications and implications. Economical aspects; Industrial Waste; Inhibition; Nitrification; Nitrogen - analysis; Nitrogen - metabolism; Other wastewaters; Oxygen - metabolism; Pollution; Sequencing batch reactor; Sewage - chemistry; Sewage - microbiology; Temperature; Waste Disposal, Fluid - methods; Wastewater; Wastewaters; Water treatment and pollution; Activated sludge; Inhibition; Sequencing batch reactor; Wastewater; Azo dye; Nitrification; Temperature effect; Chemoautotrophy; Nitrification inhibitor; Biological purification; Domestic waste water; Bioreactor; Industrial waste water; Urban waste water; Waste water purification; Acid dye; Low temperature
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2004.07.031

A municipal wastewater treatment plant (WWTP) receiving industrial dyeing discharge containing acid black 1 (AB1) failed to meet NH 3 and BOD 5 discharge limits, especially for NH 3 during the winter. Dyeing discharge was combined with domestic sewage in volumetric ratios reflecting the range received by the WWTP and fed to sequencing batch reactors at 22 and 7 °C. Analysis of the various nitrogen species revealed complete nitrification failure at 7 °C with more rapid nitrification failure as the dye concentration increased. Slight nitrification inhibition occurred at 22 °C: NH 3 removal decreased from 99.9% for the control compared to only 97.0% removal with dye addition. Dye-bearing wastewater also reduced COD removal by half at 7 °C and by one-fifth at 22 °C, and increased effluent TSS nearly three-fold at 7 °C. Activated sludge quality at 7 °C deteriorated after exposure to AB1, as indicated by excessive foaming and the presence of filamentous bacteria and by a decrease in endogenous and exogenous oxygen uptake. Decreasing AB1 loading resulted in partial activated sludge recovery. Eliminating the dye-bearing discharge to the full-scale WWTP led to improved performance bringing the WWTP into compliance with discharge limits.