[Fuzzy mathematics-based groundwater quality evaluation of six MSW landfills in Beijing]

The qualities of leachate and groundwater of six MSW landfills in wet period, water period and dry period in Beijing in 2006 were analyzed. The results demonstrated that: although BOD5 and suspended solids content in the leachate of Beishenshu landfill were within acceptable levels according to China standards, COD, ammonia, fecal coliform, BOD5 and suspended solids content in other landfills were greatly high above the permissible range of GB 16889-1997 standards. Ammonia and fecal coliform were mostly serious among assaying index. Using fuzzy mathematics, comprehensive evaluation was that: the underground water qualities of six MSW landfills are all substandard and 95% of groundwater quality was bad. The primary pollutants in groundwater of six MSW landfills were total hardness, followed by fecal coliform.