Experimental Study On A Fed-Batch Reactor For Treating Food Waste With Green Waste As The Auxiliary Material

Under the background of"four classification"of domestic waste,the collection and treatment of food waste has attracted more and more attention.Household food waste accounts for a large proportion of the total domestic waste.While realizing the reduction and harmlessness of food waste,how to realize its resource utilization is a major problem that needs to be solved urgently to complete the waste classification with high quality.Taking household food waste as the research object and green waste as the auxiliary material,12 groups of experiments were set up with a test cycle of 60 days in a small food waste composting experimental device.By investigating the treatment efficiency and the properties of composting products,the optimal operating conditions were selected,and the first-order reaction kinetic equation was constructed.The main results are as follows:（1）The comparison and selection results of operating conditions showed that in 12 groups of tests（the reactor temperature of test groups T1～T4 were set at 35℃,40℃,45℃and 50℃respectively,the initial moisture content of auxiliary materials were 15%,and the feeding load were 3:1;the initial moisture content of auxiliary materials of test groups W1～W4 were 15%,20%,25%and 30%respectively,the setting temperature were 50℃,and the feeding load were3:1;the feeding load of test groups F1～F4 were 6:1,3:1,2:1 and 3:2 respectively,the setting temperature were 50℃,and the initial moisture content of auxiliary materials were 15%）,the average daily weight loss rate of materials in test group F3（the reactor temperature was 50℃,the initial moisture content of auxiliary materials was 15%,and the feeding load was 2:1）was the largest,the degradation rate of organic matter was the fastest,and the composting reactor achieved the best treatment efficiency.Under this condition,the average daily weight loss rate of composting materials in the reactor was 82.59%,the organic matter content was reduced from 88.08%to 63.11%,and the C/N was reduced from 61.3 to 12.6.（2）The property analysis of compost products showed that among the 12 groups of tests,the two indexes of seed germination index and moisture content of compost products of test group T1 and T2（the setting temperature were 35℃and 40℃,the initial moisture content of auxiliary materials were 15%,and the feeding load were 3:1）and test group F1（the setting temperature was 50℃,the initial moisture content of auxiliary materials was 15%,and the feeding load was 6:1）did not meet the requirements of organic fertilizer（NY/T 525-2021）.The characteristics of compost products in the other 9 groups were up to standard.According to the principle of maximum reduction of food waste,the setting temperature of 50℃,initial moisture content of auxiliary materials of 15%and feeding load of 2:1 were selected as the optimal operating conditions and the weight loss rate under this condition was 88.47%.（3）The first-order kinetic model was used to simulate the organic matter degradation process of food waste aerobic compost.The effects of reactor temperature,initial moisture content of auxiliary materials and feeding load on the reaction rate constant were comprehensively considered.According to the change of organic matter content with time,the kinetic parameters of the organic matter degradation process were linearly fitted to obtain the reaction rate constant under different process conditions.When the reactor temperature was50℃,the initial moisture content of auxiliary materials was 15%and the feeding load was 2:1,the reaction rate constant was the largest,and the first-order reaction kinetic equation was ln（C₀/C）=0.0116t.The research results provide an alternative technical path for the reduction and resource treatment of food waste.