Performance of a full-scale biofilter with peat and ash as a medium for treating industrial landfill leachate: a 3-year study of pollutant removal efficiency

Abstract

Shredder residues of end-of-life vehicles and white goods are a complex waste stream, which nowadays most often is disposed of at industrial landfills. This paper describes the most important findings concerning the complex composition of the landfill leachate and its on-site, year-round treatment under cold-climate conditions. A 3-year investigation has confirmed that concentrations of different types of pollutants, most of them at low initial concentrations, can be simultaneously reduced in vertical-flow biofilters consisting of a mixture of peat and carbon-containing ash. For metals such as Mn, Cu, Sn, Cd, Pb, Fe and Ni the average removal was 73, 72, 66, 60, 55, 55 and 37%, respectively. An average reduction of NH₄-N (45%), N_tot (25%), total organic carbon (30%), dissolved organic carbon (28%) and suspended solids (38%) was also obtained. A good reduction was achieved for phenols (between 75 and 95%), polychlorinated biphenyls (between 22 and 99%), and gas chromatography—mass spectrometry amenable pollutants, considered at initial concentration above 50 µg L ^—1 (between 80 and 100%). The performance of the biofilter system was good in spite of large variations of inlet concentration during the considered period.