Important aspects of long-term production and treatment of municipal solid waste leachate

Abstract

Less than 30 out of a total of 250 active municipal solid waste (MSW) landfills in Norway use on-site biological leachate treatment systems. One of the most important aspects with regard to landfills is the treatment of the expected polluting leachate emissions, requiring simple and low-cost systems. A combination of aeration, dams and filtering techniques is likely to result in the best treatment options. Biological treatment systems, like aerated lagoons or sequenced batch reactors in combination with natural systems like soil infiltration, spray irrigation, filtration or constructed wetlands can be cost-effective systems for MSW leachate treatment in Norway. Aerated lagoons appeared to be an efficient treatment stage for landfill leachate treatment in cold climates. The hydraulic retention time should be >20 d to keep the nitrifiers in the lagoon during periods with low temperatures. Landfills can be grouped into categories depending on landfill size, age, hydrology and climate before evaluating sampling programmes prior to treatment system installation and during operation. Simple filtration techniques with bark and crushed concrete can significantly improve leachate quality during treatment and remove nitrogen, colour, heavy metals and pesticides, buffer the pH and add phosphorous.