| The proportion of food waste in urban solid waste is very high.At present,the cost of processing food waste is too high and it is easy to cause secondary pollution to the environment.At the same time,the sewage treatment plant has a problem of lack of carbon source.The lack of sufficient carbon source is an important reason for limiting the efficiency of sewage treatment denitrification.The food waste generated in the family can be processed on-site by the pulverizer installed under the sink.In order to implement the concept of "treatment of waste by waste",a new type of external carbon source can be used to solve the sewage treatment by utilizing the characteristics of high organic content of food waste.The problem of the lack of carbon sources in the factory has reduced the source.Based on the previous research foundation of traditional external carbon sources,this experiment explored the denitrification,denitrification and dephosphorization of the new external carbon source,which is a new type of external carbon source,which is based on kitchen waste and activated sludge in the school canteen.ability.(1)After collecting and pre-treating the kitchen waste,it is mixed with the activated sludge from the sewage treatment plant in different proportions and fermented,and the optimal mixed culture ratio is determined through experiments.When the culture ratio of activated sludge to kitchen waste reaches 1:4,the organic content of the mixed fermentation broth of kitchen waste is the highest,the COD content is 16g/L at room temperature 23±1℃,8g/L at 17±1℃,p H The lowest value is 3.2,the best degree of fermentation.(2)The single-variable method was used to simulate the sewage treatment of the food waste fermentation broth cultivated at the optimal mixing ratio,and the optimal process parameters were determined.Before and after adding the kitchen waste mixed fermentation broth,the COD removal rate was increased from 62% to 85%,and the organic substance removal effect was significantly improved;the biochemical effect was weak,and the removal time of nitrogen removal was longer.With the extension of the reaction time,the total nitrogen removal The rate increased from 20% to 75%.Considering the influence of various indicators comprehensively,the best process parameters are determined: 27 g for each 2.8L of domestic wastewater treated with a COD content of 16g/L of kitchen waste mixed fermentation broth,and each 1.8L of treated domestic wastewater for a COD content of 8g /L of food waste mixed fermentation broth 33g;total reaction time 12 h,at this time the food waste mixed fermentation broth as a denitrifying carbon source can increase the carbon and nitrogen of the raw sewage to 10.(3)In the simulated wastewater treatment experiment of the SBR device,after processing 2.8L of sewage and adding 27 g of kitchen waste mixed fermentation broth with a content of 16g/L,the COD removal rate can reach up to 88%,the total nitrogen removal rate increased to 79%,ammonia nitrogen The removal rate is kept above 75%.The experimental results show that the raw materials of kitchen waste mixed fermentation broth are easy to obtain and simple to prepare.Using it as a raw material to prepare an external carbon source to treat sewage is better than the traditional activated sludge method for the treatment of COD,ammonia nitrogen and total nitrogen in sewage.(4)Add 50 g of machined and ground iron powder to the kitchen waste mixed fermentation broth for 3-5 days,then add it to domestic sewage with a p H of 6.5 for 8 hours.The combined process has a good removal effect of phosphorus and COD,and the effluent phosphorus The concentration can reach the national level A standard for 14 consecutive cycles. |
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