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Nitrate Removal of Fluidized-Bed Biofilm Reactors Using Starch / Polyvinyl Alcohol Blends as Carbon Source and Carrier Simultaneously at Low Temperature

A kind of controlled-release carbon source, starch / polyvinyl alcohol blends (SPVA), was used as both carbon source and biofilm supporter in laboratory-scale fluidized-bed biofilm reactors (FBBRs) to remove nitrate from groundwater. Results show: when the influent nitrate concentration was 100 mg-N /L, FBBRs packed with SPVA can effectively remove nitrate from groundwater at the condition of temperature 20 °C, hydraulic resident time (HRT) 4 h. The effluent nitrate can meet with the Chinese drinking water standards at low temperature (15-2 °C) by adjusted the HRT of FBBRs. The denitrification rate declined nonlinearly with the decrease of temperature and changed sharply in the range of 20-15 °Cand 10-5 °C.