Author(s)

P. Champagne & M. Khalekuzzaman

Abstract

In recent years, researchers have identified peat as an alternative low-cost filter medium for on-site wastewater treatment, including landfill leachate. Peat possesses several physical, chemical and biological characteristics that make it a favorable filter medium for the mitigation of contaminants. The effectiveness and the impact of clogging of peat biofilter in terms of organic (COD, CBOD5), ammonia (NH3-N) and total suspended solid (TSS) loading are crucial in the operation of such systems. The main purpose of this research was to evaluate the performance of a bench-scale sequential aerated peat biofilter system treating landfill leachate at different hydraulic loading rates (HLRs) under continuous flow condition. The system consists of two major components: an aeration chamber with an attached growth media, followed by a peat biofilter. The leachate was aerated at a constant air flow rate of 3.40 m3/day for a hydraulic retention times (HRTs) of 2 or 5 days. The aerated leachate was then fed to two sets of triplicate peat columns, which were operated at average HLRs of 8.28 cm3/cm2/day and 10.82 cm3/cm2/day. The result of the study showed that similar CBOD5, COD, NH3-N and TSS removal efficiencies and column life expectancies could be obtained from the two different hydraulic loading rates to the peat biofilter. 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, respectively, in the peat columns after 6 weeks of operation. Keywords: peat, landfill leachate, aeration, biofilm, hydraulic loading, leachate treatment.

Keywords

peat, landfill leachate, aeration, biofilm, hydraulic loading, leachatetreatment.