Study On Carbon Source Supplement For Denitrification

The COD of municipal wastewater is around 200mg/L in Southern China area. The problem of lacks of carbon source for nitrogen removal is widely noticed.The most popular method is to add methanol as the supplemented carbon source,but the high price blocked its use.The present study concentrated on the research of new additional carbon source.The straw is studied as carbon source which is fixed in a plug reactor.HRT is a very important factor which influences the removal efficiency.The highest removal efficiency is 86%,and the lowest concentration of NO₃-N in effluent is 5.1mg/L.The effluent COD is under 63.2mg/L.The residual sludge is hydrolyzed to generate VFAs for denitrification.SCOD increases as HRT prolongs.The acetic take a percent of 48%in the 6 VFAs,and the total VFAs-COD take a percent of 40%in SCOD_T.Increasing HRT is useful in getting more quality carbon source.When the hydrolyzed sludge VFAs are used as carbon source for denitrification, COD/N influences the denitrification.It was noticed that only when the COD/N is higher than 8.4,complete denitrification can be realized.When COD/N is more than 10,COD/N only influences the denitrification rate.Comparing the effect of sodium acetic,lixivia of rubbish,stabilized lixivia,hydrolyzed sludge VFAs and starch as the carbon sources for denitification,we found that the hydrolyzed sludge VFAs present the best denitrifaction rate and lixivia of rubbish offered the best rate of carbon utilization.The denitrification rate was the slowest when starch as the carbon source.