Research On Kitchen Waste Hydrolysis Products As Alternative Carbon Source In Treatment Of Percolate Denitrification And Pilot-scale Study

The late landfill leachate is poor in biochemical treatment and has high concentration of ammonia nitrogen,imbalanced in carbon to nitrogen ratio.Before the biochemical treatment,the late landfill leachate should be improved on biodegradability.There is a kind of acidogenic liquid rich in volatile fatty acids(VFAs)producted from food waste anaerobic hydrolysis acidification,can be used as an alternative carbon source to enhanced the leachate biological nitrogen removal.In this study,the acidogenic liquid was used as alternative carbon source to enhance the leachate biological nitrogen removal to investigated whether it is useful in denitrification,and the influence of different conditions was studied:Used two kinds of acidogenic liquid as alternative carbon source in denitrification treatment of leachate and compared with the traditional carbon source sodium acetate.The VFAs concentrations of acidogenic liquid a and acidogenic liquid b were 38.6g/L and 42.1g/L,respectively.The concentrations of ammonia were 415mg/L and 1405mg/L respectively.When the condition of C/N was 4,5.5 and 7 in leachate denitrification,the nitrate removal process was divided into two stages,the maximum denitrification rate of acidogenic liquid a was 15.3~20.9mg NO3-N/(g VSS · h)and the maximum denitrification rate of acidogenic liquid b was 14.4~20.1 mg NO3-N/(g VSS · h).During the denitrification there were both nitrite accumulation appeared,the maximum nitrite accumulation concentration of acidogenic liquid a was 92.3~130.4mg/L,the maximum nitrite accumulation concentration of acidogenic liquid b was92.6~151.5mg/L.The denitrification rates of food waste acidogenic liquid and sodium acetate in landfill leachate treatment were almost the same.Under the optimum C/N,the concentration of total nitrogen,ammonia,COD value could reach the standard.Compared the leachate denitrification process using acidogenic liquid as alternative carbon in 15 ℃ and 25 ℃ two kind of temperature,found that temperature indeed impact the denitrification process.The maximumdenitrification rate was 14.9~15.3mg NO3-N/(g VSS · h)in 15 ℃ and the maximum denitrification rate was 15.0~26.7mg NO3-N/(g VSS·h)in 25℃.The maximum denitrification rate was 9.1~14.8mg NO3-N/(g VSS·h)in the low leachate loading denitrification.It was slightly lower than the high load leachate.Compared with the high and low load leachate effluent,it was found that the reduction of the leachate load could effectively improve the water quality and reduce the amount of carbon source.The two project of food waste hydrolysis production of carbon source were completed in Changzhou and Suzhou.The treatment cost of 1 tons food waste in Changzhou project was 6.83 yuan;after using the acidogenic liquid from Suzhou food waste hydrolysis project as alternative carbon source for landfill leachate treatment,the effluent quality improved significantly and total nitrogen,COD concentration reduced greatly.Overall,the food waste hydrolysis acidification process to produce rich VFAs acidogenic liquid for leachate denitrification effect is good and have high economic benefit.