Chapter 5 - Leachate Treatment Engineering Processes

Abstract

Currently, the predominant leachate treatment processes can be listed as pretreatment + anaerobic treatment + MBR + NF + RO + concentrated liquid elimination. Pretreatment processes may be sand filtration, flocculation, or aged refuse bioreactor. Evaporation developed as mechanical vapor compression (MVC) may be used for the deep concentration of concentrated liquid to reduce its volume and recovery of salts. Traditionally, the ultimate purpose of leachate treatment is to reduce the pollutants to the regulated discharge standard values. Nevertheless, the current treatment trend is to recycle the leachate effluent without any discharge, though it is really very difficult. In general, the leachate in an incineration plant should be treated and recycled within the plant without any discharge into the water receivers, in which the concentrated liquid may be used for the fly ash stabilization process or rejected to the furnace and the clear water for cooling water. In this chapter, different leachate treatment projects are provided as reference, with a treatment scale from 100t/d to 3200t/d. These engineering examples include leachate treatment for a municipal solid waste incineration plant using pretreatment + anaerobic treatment + MBR + NF + RO with a scale of 800t/d in Ningbo (Case 1), leachate treatment plant using biological-membrane bioreactor-NF-RO system with a scale of 800t/d in Shanghai (Case 2), leachate treatment reconstruction project for landfill and transfer station leachate using biological and DTRO processes in Jiangsu (Case 3), allocation process optimization for different sources of leachate in Shanghai (Case 4), NF-derived concentrated liquid treatment using anaerobic-flocculation-decoloring-two-stage-oxidation-fluidization tower with a scale of 100t/d in Shanghai (Case 5), leachate treatment using ozone oxidation-biochemical coupling technology (Case 6), leachate treatment for municipal solid waste transfer station using bio-strong technology and bio-strong nitration technology (Case 7), leachate pretreatment for meeting sewage influent quality at a municipal solid waste incineration plant using nitrification-denitrification and ultrafiltration (MBR) system (Case 8), integrated aged refuse bioreactor for leachate treatment in Shanghai Refuse Landfill (Case 9), leachate treatment for a municipal solid waste fluidized bed incinerator plant using medium temperature anaerobic + anoxic + aerobic MBR + reverse osmosis treatment technology (Case 10), leachate treatment for a sanitary landfill in the cold region using membrane biochemical reactor (MBR) + nanofiltration (NF) + reverse osmosis (RO) (Case 11), leachate treatment for incineration plant’s second phase project in the warm region with zero emission (Case 12), and DTNF-HPRO-evaporation-advanced oxidation-crystalline waste solidification system for zero emission treatment technology for concentrated liquid (Case 13). Relevant Chinese standards, of great importance to select treatment techniques, are also mentioned. Detailed specification, structural description, main equipment, working performance of each unit and cost accounting are all provided.