The Design And Optimization Research Of Immobilized Microbial Reaction Used For Leachate Treatment

Landfill treatment is the common method of domestic waste treatment at the present stage in our country. Leachate is a high concentration of organic matter and high ammonia-nitrogen content and toxicity of refractory wastewater which is produced by the rain erosion, subsurface or surface infiltration and self-fermentation in the process of landfill. Immobilized microorganisms technology is a simple operation, high efficiency and low cost, the stable operation of wastewater bio-treatment technology. It can be used to treat refractory wastewater, high concentration organic wastewater and wastewater containing heavy metals.Based on the existing structures of immobilized bioreactor, this paper designed an immobilized microbial reactor for leachate treatment. By studying the gas-liquid phase oxygen transfer mechanism in the reaction tank and gas-liquid two-phase flow pattern, provided the theoretical basis for numerical simulation. Using mixture model and standard turbulence model of computational fluent dynamics software Fluent, the influence of aerator installation position and aeration quantity on the hydrodynamics characteristics of gas-liquid two-phase flow in the reaction tank was researched. By considering liquid low rate in reaction tank and fluid flow effects, confirmed that the best aerator installation height was 450mm and the best aeration quantity was 0.43kg·h-1. By designing water oxygenation experiment, investigated the oxygen transfer rate and oxygen saturation value of the reaction tanks under different aerator installation position and different aeration quantity. Best design drawn from the analysis is consistent with the simulation results. The optimized reactor was applied to the experimental study of leachate treatment. Results showed that the removal rate of COD was 34% and the removal rate of NH3-H was 65%. Applied the reaction to the municipal solid waste landfill of guangxi mashan, results showed that the removal rate of COD was 30%-45% and the removal rate of NH3-H was 75%.