Effect Of Percolation-hydrolysis On Separation And Upgrading Of Kitchen Waste

Kitchen waste is the main component of MSW in China,it has the characteristics of high moisture content,high organic matter content and easy to corrupt.The higher efficient treatment of KW is a major challenge for the construction of MSW classification and treatment system in China.In view of the above problems,this paper proposes to pretreat KW by percolation,dividing KW into hydrolysate and solid residue.Hydrolysate is a suitable substrate for anaerobic digestion,and solid residue is incinerated.Thought this kind pretreatment technology to improve the comprehensive environmental performance of KW,provide feasible technology for MSW classification and treatment in China.The simulated kitchen waste was made by the characteristics of real kitchen.Firstly,the conditions of leaching and hydrolysis were optimized by lab-scale equipment.The results showed that percolation had the best effect on the treatment of kitchen waste when the liquid to solid ratio was 4L/kg and the hydraulic retention time was 4 days.When the liquid to solid ratio was 4 L/kg,the yield of VFAs in the hydrolysate was the highest,and acetic acid was the main component of VFA.Sequence batch experiments showed that HRT was 4 days,the pH of hydrolysate was about 5.3,the concentration of VFA was about 7050 mg/L,the concentration of COD was about 25~350 mg/L,and the acidification rate reached 40%,which was suitable for anaerobic digestion.Based on the optimization of operation parameters under laboratory conditions,pilot-scale study on KW was carried out.The results showed that the hydrolysate pH was above 4.7,VFA concentration was about 13860~22400 mg/L,and the average calorific value of solid residue after dehydration was above 10728 kJ/kg.It can be concluded that it is technically feasible to treat KW by percolation-hydrolysate anaerobic digestion-solid phase residue incineration.The comprehensive environmental effects of KW scenarios were assessed by life cycle inventory analysis method.The results show that the pretreatment of KW by percolation,anaerobic digestion of hydrolysate,landfill of biogas residue,and direct incineration of solid residue are ideal treatment methods.