A Semi-Passive Peat Biofilter System for the Treatment of Landfill Leachate

Pascale Champagne, Mohammed Khalekuzzaman



Peat is an alternative low-cost filter medium for on-site wastewater treatment, including landfill leachate. The effectiveness of peat biofilter under various organic, ammonia and total suspended solid loadings is critical in the operation of such systems. The purpose of this study was to evaluate the performance of a bench-scale sequential aerated peat biofilter system treating landfill leachate at different hydraulic loading rates under continuous flow condition. The leachate was aerated at a constant air flow rate of 3.4 m3/day for HRTs of 2 or 5 days. The aerated leachate was then fed to peat columns, operated at average hydraulic loading rates of 8.28 cm3/cm2/day and 10.82 cm3/cm2/day. Similar CBOD5, COD, NH3-N and TSS removal efficiencies and column life expectancies were obtained at the two hydraulic loading rates. However, the HRT in the aeration basin was found to significantly increase the life expectancy of the peat biofilter by reducing the overall contaminant loading to the biofilter. For a HRT of 5 days and constant air flow rate of 3.4 m3/day, 99% NH3-N was removed in the aeration tank after 3 weeks. Removal efficiencies above 80%, 90% and 86% were noted for COD, CBOD5 and NH3-N after 6 weeks of operation.

Keywords: Peat; landfill leachate; aeration; biofilm; hydraulic loading; leachate treatment