Chapter 3 - Biological Treatment Processes for Leachate

Abstract

Humic-like matters can be removed in mature leachate with a hollow ellipsoid structure sludge inoculated from decayed soil. The microorganisms in decayed soil are found to be capable of decomposing the humic-like matters evidently using an anaerobic–aerobic/anoxic bioprocess in two sequencing bio-reactors. The intensities of fluorescence peaks A and C of leachate effluents are 71.66% and 48.75% lower than those of influents, respectively, which indicate the extraordinary degradation ability of microorganisms inoculated from the decayed soil. Meanwhile, a kind of distinctive hollow ellipsoid structure sludge, organized by tiny soil particles, is observed, which may favor the humic-like matters’ decomposition. Deep Shaft Aerobic Bioreactor (DSAB) treatment for leachate, another leachate biolodical treatment process, shows 84–94%, 59–67%, 77–87%, and 80–94%, respectively, of removal rate of NH3-N, TN, COD, and TOC at low temperature (-3~15°C) in winter. When COD concentration of the effluent is in the range of 900–1300mg/L, oxygen utilization efficiency of the DSAB could be raised to 60–90%, power consumption is reduced by 70%, saving land by about 40% and processing costs by 52%, compared to the activated sludge sludge method. Aged refuse contains a huge quantity of microorganisms that can biodegrade organic pollutants in leachate. Hence, aged refuse is used as the biofilter for the pretreatment of leachate. Integrated anaerobic and aerobic leachate treatment processes, reverse osmosis, and nanofiltration processes are described. Superfine/Nanometer Iron Powder-Activated Carbon Micro-Electrolysis Treatment and Modified Chitosan-Based Organics Treatment are used for the deep treatment for the effluents from DSAB, aged refuse biofilter, and other biological treatment processes. Food waste can be added as the high quality supplementary carbon source for the mature leachate and the food waste press liquid has a better carbon source supplement effect than food waste slurry. The addition proportion of press liquid should not exceed 20%. The conventional anaerobic and aerobic treatment processes and their combinations with aged-refuse biofilter for mature landfill leachate treatment, and Circulation Jet Reactor (CJR) for general leachate are also fully described.