Biodenitrification with sweet potato lixivium as carbon source
以红薯浸泡液为碳源的生物反硝化

In order to choose the appropriate carbon source in the biological nitrogen removal of low C/Nratio wastewater,a stirred tank was used to soak the starch matter to release carbon source,and the experiment of biodenitrification with sweet potato lixivium as the carbon source in a submerged biological filter was carried out.The experimental results showed that when 20 g sweet potato was added into 2 L water with stirring at 250 r/min for 3 h and without stirring for 1 h.the average concentration of released COD of the lixivium was 5 921 mg/L and the highest concentration was above 7 000 mg/L after 2 d.The average removal rates of total nitrogen,nitrate-nitrogen,nitrite-nitrogen and ammonia-nitrogen achieved 88.6%,91.6%,88.2%,54.8%respectively and the effluent COD concentration average was maintained below 30 mg/L,when the sweet potato lixivium and the wastewater were separately pumped into the reactor with the flow ratio of 1:50.When the COD concentration of the sweet potato lixivium was about 5 700 mg/L,the remoral rate of total nitrogen was 95.3% when the nitrite-nitrogen to nitrate-nitrogen concentration ratio was 3:2.while the removal rate of total nitrogen was 88.2% when the nitrite-nitrogen to nitrate-nitrogen concentration ratio was 2:3.The research indicated that the sweet potato lixivium was a kind of economical and suitable carbon source.and it was feasible to use the sweet potato lixivium in the biodenitrification for the treatment of low C/N ratio wastewater.