The leachate of waste incineration plant mainly comes from waste storage materials, and its main characteristics are high organic pollutant CODcr and BOD5 indicators, and high ammonia nitrogen. The treated effluent meets the standard in Table 2 of the "Pollution Control Standard for Domestic Waste Landfill Sites " ( GB16889-2008 ). The main pollutant indicators of the leachate produced by the waste incineration plant are shown in the table below. Designed water quality unit of incoming and outgoing water: mg/L ( except pH )
Waste incineration leachate water quality
The amount of landfill leachate produced is mainly affected by the composition, moisture and storage days of the waste entering the plant. The content of kitchen waste and peel waste are the main factors affecting the quality and quantity of the leachate. Due to regional differences, the composition and moisture content of garbage in various parts of the country are quite different. Generally, the moisture content of garbage is about 20% to 50%, and the water content of garbage can even reach more than 70%.
The separate treatment methods of waste incineration leachate include biological method, physical method, chemical method, biological method, physical combination method-MBR technology, etc.
Biological methods are mainly aerobic biological treatment, anaerobic biological treatment and the combination of the two. The physical method is mainly the application of membrane technology, including MBR, ultrafiltration, nanofiltration and reverse osmosis. The advantage of membrane technology is that the effluent quality is better. , Can meet higher emission requirements. The chemical method mainly uses strong oxidants to decompose pollutants in wastewater.
With the continuous advancement of technology, the MBR process is more and more used in the treatment of waste incineration leachate. Taking into account the water quality characteristics of the leachate, the MBR flat membrane, with its excellent anti-pollution performance, can operate stably for a long time in the treatment of leachate projects. . The MBR flat membrane replaces the traditional secondary sedimentation tank. The microorganisms are completely trapped in the biochemical system through the interception effect of the membrane, and the hydraulic retention time and the sludge age are completely separated, so that the sludge concentration in the biochemical reactor is from 3 to 5 g. /L is increased to 10～15g/L, thereby increasing the volume load of the reactor, reducing the volume of the reactor, greatly prolonging the age of sludge, and increasing the number of high-concentration microorganisms, so that the ammonia nitrogen in the wastewater can be completely Nitrification improves the removal of organic pollutants.