Performance of sludge settling property under nitrite existing conditions
Xiong Yang1, Yongzhen Peng1, Jichen Song1
1a Engineering Research Center of Beijing ,Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering , Beijing University of Technology , Beijing 100124 , PR China.
Abstract:
Performance of sludge settling property and filamentous bacteria growth under nitrite existing conditions were studied. Biomass was cultivated in three anoxic/aerobic sequencing batch reactors (SBRs). Two of them were dosed with nitrite to the anoxic and aerobic phases, respectively, leaving the remaining one without nitrite added as control. The results showed that nitrite had a significant negative effect on sludge settling property, a serious bulking (sludge volumn index (SVI)>350 mL/g) and a limited bulking (SVI about 220 mL/g) were observed in the anoxic- and aerobic-nitrite-dosed systems, respectively. Filamentous bulking more easily happened when nitrite existed in the anoxic conditions than in the aerobic conditions. There was almost no differences in terms of filamentous species between the nitrite-dosed and non-nitrite-dosed systems, which indicated that nitrite did not play a key role in determining the filamentous species. The nitrite existing under both anoxic and aerobic conditions showed a negative effect on microbiological intracellular storage capability, the maximum polyhydroxyalkanoates (PHA) production and the maximum specific PHA production rate in nitrite-dosed systems were both significantly lower than that in the control system.
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