Process control factors influencing Nocardia populations in activated sludge

Authors: Cha, Daniel K.; Jenkins, David; Lewis, William P.; Kido, Wendell H.

Source: Water Environment Research, Volume 64, Number 1, January/February 1992 , pp. 37-43(7)

Publisher: Water Environment Federation

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Bench-scale activated sludge experiments were conducted on Sacramento, California, primary effluent to determine the effect of various process control factors on Nocardia populations in activated sludge. It was possible to wash Nocardia out from activated sludge at a sufficiently low MCRT. The washout MCRT for bench-and full-scale activated sludge plants was related to the temperature by the Arrhenius equation. Foam trapping was shown to be a major factor in increasing Nocardia populations in activated sludge. The optimum pH for Nocardia growth in activated sludge was approximately 6.5. Aerobic selectors were effective in controlling Nocardia at an MCRT of 5 days but not at an MCRT of 10 days. Anoxic selectors controlled Nocardia in a nitrifying activated sludge at an MCRT of 12 days.

Keywords: Nocardia; foaming; mean cell residence time; pH; primary effluent; selectors; sludge; temperature

Document Type: Research Article


Publication date: January 1, 1992

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  • Water Environment Research® (WER®) publishes peer-reviewed research papers, research notes, state-of-the-art and critical reviews on original, fundamental and applied research in all scientific and technical areas related to water quality, pollution control, and management. An annual Literature Review provides a review of published books and articles on water quality topics from the previous year.

    Published as: Sewage Works Journal, 1928 - 1949; Sewage and Industrial Wastes, 1950 - 1959; Journal Water Pollution Control Federation, 1959 - Oct 1989; Research Journal Water Pollution Control Federation, Nov 1989 - 1991; Water Environment Research, 1992 - present.
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