Abstract: The study was carried out on the volume reduction and main pollutants removal of recirculated landfill leachate with different diluted concentrations by irrigation on the soil planted with and without Cynodon dactyton. The results showed that during one field season, the average volume reduction rate of the recirculated landfill leachate by soil planted with Cynodon dactyton was 7.7~11 mm/d, and among it the undiluted leachte one was 7.7 mm/d, while 7 mm/d by soil without vegetation, and the former was correlated with the dry weight of the grass; the dry weight of the recirculated landfill leachateirrigated grass was larger than the tap waterirrigated one, and decreased with rising of leachate concentration; 89%~99% of NH3-N and 68%~93% of COD in the recirculated landfill leachate was removed by the soil with  Cynodon dactyton respectively, while 70%~93% of NH3-N and about 65% of COD by the soil without vegetation. NH\-3-N was removed mainly by conversion to NOx-N and vegetation intake.Recirculated landfill leachate irrigation benefits to its volume reduction and pollutants removal, especially on soil with Cynodon dactyton. The results show that it is feasible to irrigate the landfill closure system with recirculated landfill leachate in practice.

Key words: recirculated landfill leachate, irrigation treatment, volume reduction, NH3-N, COD, Cynodon dactyton