Evaluating the performance of subsurface horizontal flow constructed wetland for tertiary treatment of sanitary landfill leachate

Abstract

The difficulty in detecting and quantifying the typical composition characteristics of landfill leachate, limit successful treatment of it. High quality effluent that can be discharged to surface waters could be achieved by using the two stage leachate treatment systems with a constructed wetland at the final stage. This pilot scale study was conducted with the aim of evaluating the tertiary treatment of pre-treated leachate obtained from Sanitary Landfill located at Dompe, by a subsurface horizontal flow constructed wetland comprising Phragmites karka and Calicut tiles as substrate. The removal efficiency of BOD5, COD, TSS, NO3--N and PO43--P was evaluated. The study period was from June to August 2017. Sixty liters of diluted pre-treated leachate (i.e. Containing 80% of the pre-treated leachate by volume) was fed per day with a hydraulic retention time of 1 day. Concentration based average removal efficiency of the system was 63% for BOD5, 62% for COD, 96% for TSS, 49.11% for NO3- -N and 85.28% for PO43--P. Long term research is necessary to examine the effects of continuous feeding and shock loadings on the growth response of Phragmites karka.