Three-stage aged refuse biofilter for the treatment of landfill leachate

A field-scale aged refuse (AR) biofilter constructed in Shanghai Refuse Landfill, containing about 7 000 m3 aged refuse inside, was evaluated for its performance in the treatment of landfill leachate. This AR biofilter can be divided into three stages and can manage 50 m3 landfill leachate per day. The physical, chemical, and biological characteristics of AR were analyzed for evaluating the AR biofilter as leachate treatment host. The results revealed that over 87.8%--96.2% of COD and 96.9%--99.4% of ammonia nitrogen were removed by the three-stage AR biofilter when the influent leachate COD and ammonia nitrogen were 5 478-10 842 mg/L and 811-1 582 mg/L, respectively. The final effluent was inodorous and pale yellow with COD and ammonia nitrogen below 267--1,020 mg/L and 6--45 mg/L, respectively. The three-stage AR biofilter had efficient nitrification but relative poor denitrification capacity with a total nitrogen (TN) removal of 58%--73%. The external temperature of AR biofilter did not influence the total ammonia nitrogen removal significantly. It was concluded that the scale-up AR biofilter can work very well and can be a promising technology for the treatment of landfill leachate.