Efficient Removal of NH_4^+ Accumulated during Anaerobic Treatment of Distillery Wastewater from Shochu Making

概要

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Propionate and NH_4^+ were accumulated in the effluent during anaerobic treatment of five-fold diluted distillery wastewater from shochu making. Propionate could be removed efficiently during biological denitrification by the addition of NO_3^- (4.2 g/l) to the anaerobically treated wastewater. At a hydraulic retention time of more than 2h, a TOC removal efficiency of 90% could be achieved. The wastewater was then treated aerobically by biological nitrification. With a hydraulic retention time of more than 14 h the efficiency of reduction of NH_4^+ could be maintained above 97%. In order to reduce the amount of NO_3^- addition necessary for the removal of propionate, simulataneous removal of propionate and NH_4^+ was studied by recirculating the effluent from a nitrification process to a denitrification process using denitrification and nitrification reactors connected in series. At a recirculation ratio of 2,the amount of NO_3^- that had to be added was reduced to 0.3 g/l of anaerobically treated wstewater, which corresponds to 6.9% of the theoretical value. Under the same conditions except for the addition of NO_3^- at 1.0 g/l, TOC and BOD in the effluent from the nitrification were 23 and 5 mg/l respectively, which are sufficiently low to allow discharge into river water. Moreover, the NO_3^- concentration in the effluent decreased with increases in the recirculation ratio.
社団法人日本生物工学会の論文
1993-04-25