Study On Technology Of Ultrasonic Pretreatment Combined With Aerobic Composting Of Kitchen Waste

With the rapid development of catering industry,the amount of food waste is increasing rapidly.Improper disposal of food waste will do serious harm to the ecological environment.As an environment-friendly technology,ultrasonic pretreatment is widely used in environmental treatment.However,the energy consumption of ultrasonic pretreatment is large,at the same time,the treatment effect is guaranteed and the energy consumption is reduced.In this p,how to use the technology of ultrasonic wave and alkaline hydrolysis to improve the utilization rate of organic matter in food waste was studied.The solubility of water-soluble COD,soluble sugar and ammonia-nitrogen in liquid phase were compared by Ultrasonic Pretreatment,alkaline pretreatment and ultrasonic alkaline treatment,three levels of three factors were chosen to design the orthogonal experiment,and the effect of three factors on the soluble sugar dissolution rate was analyzed.According to the influencing factors of aerobic composting process,the optimal reaction condition of aerobic composting was determined by four factors,which are mixture ratio of materials,aeration rate,air supply mode and initial composting temperature,the effect of ultrasonic pretreatment on the maturity of aerobic composting of pretreated kitchen waste was investigated.In the experiment of Ultrasonic Pretreatment and alkaline pretreatment of food waste,it was found that both pretreatment methods could promote the release of organic compounds from food waste.In the joint treatment of ultrasonic alkaline hydrolysis,it was found that preadding a certain amount of alkali to the food waste can promote the ultrasonic decomposition of the food waste,making the water-soluble COD and soluble sugar of the food waste more efficient,under the same ultrasonic time,the influence of three factors on soluble sugar dissolution was followed by the time of alkaline hydrolysis,the ultrasonic power and the p H of alkaline hydrolysis.The ultrasonic energy density was 0.65 w/ml,the ultrasonic time was 20 min,the p H value was 8 and the time was 5 h.In the experiment of optimizing aerobic composting condition,the optimum mixture ratio of food waste,sludge and conditioner is 1:2:1,and the optimum ventilation rate is 0.4 m3/h,the optimum initial temperature was 35 ℃.the degradation rate of organic matter and moisture content were 39.74% and 38.93% respectively.At the end of composting,the pretreated compost reached maturity.The compost was dark brown and smelled of soil.The GI value was 104.04% and 73.77%,respectively.No E.coli was found in the two piles,and the content of E.coli in the pre-treated was lower than that in the untreated.The high temperature duration of pretreated composts was longer than that of untreated composts.The degradation rate of organic matter at the end of composting was about51.23%,and the p H value was maintained at 7.5,at the end of the experiment,the time for the reactor to reach the stable period is obviously shortened.Ultrasonic pretreatment combined with alkaline hydrolysis can accelerate the maturity of compost and promote the maturity of final products,which can promote the growth of plants.