The Population Dynamics of Nitrifiers in Ammonium-Rich Systems
Abstract:Non-optimal pH, dissolved oxygen concentration, the presence of toxic substances, or the influence of grazers are known to cause disturbances in nitrification. Because activated sludge is a mixture of different organisms, bacteria, and higher organisms, the stability of processes such as carbon removal, nitrification, denitrification, and dephosphatation depends on a range of interactions. These interactions occur both between and within trophic levels. Understanding of the ecology of microorganisms involved in bioprocesses is essential for effective control of startup and operation of a particular process. The aim of the study was to gain further insight into the dynamics of nitrifiers in activated sludge at various sludge ages while treating higher concentrations of ammonium. The results confirmed the importance of Nitrosococcus mobilis and Nitrobacter sp. as the dominant nitrifiers responsible for nitritation and nitratation, respectively, in the presence of unlimited ammonium. The size of the dominant bacteria colony was larger compared to the other species present and reached 25 µm. Problems with nitrification occurred in all high-ammonium loaded reactors. The dynamics of nitrifier population was monitored by oxygen uptake rate (OUR) using a test enabling the OUR measurement separately for ammonium-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). The results reveal the hypersensitivity of nitrifiers to the substrate and products of incomplete nitrification.
Document Type: Research Article
Publication date: December 1, 2011
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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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