Efficient treatment of mature landfill leachate with a novel composite biological trickle reactor developed using refractory domestic waste and aged refuse

Abstract

Municipal solid waste classification is a major livelihood project, while the classified materials are deficiently utilized, especially the inert waste. In this study, a composite biological trickle reactor, packed with foam concrete, waste textile, animal bone and aged refuse, was developed for the treatment of mature landfill leachate, and the function of reaction factors were investigated systematically. Results indicated that under the optimum conditions with mixed filler, temperature of 30 °C, hydraulic loading of 40 L/(m3·d), and aeration rate of 1.8 L/(h·L), the average removal rates of chemical oxygen demand, total nitrogen, ammonia nitrogen and total phosphorus were 85.02%, 76.00%, 99.90% and 96.83%. The reactor presented well buffering performance after 100 days operation, with a slightly accumulation of organic and nitrogen substances. Biological analysis showed that the main phyla in all fillers were Actinobacteria and Proteobacteria. The microbial diversity and richness of waste textile were inferior to those of animal bone, aged refuse and foam concrete. In the operation system, the alternate aerobic–anoxic–anaerobic environment was structured, and the contaminants removal was due to the comprehensive function of adsorption, promotional biotreatment and chemical precipitation. All the results demonstrated that this novel trickle reactor was an excellent choice for leachate treatment because of the low cost and superior efficiency.