Evaluation of filter material for treatment of different types of wastewater

This paper presents an evaluation of the suitability of a mixed absorbent based on peat and carbon-containing ash for treatment of wastewaters, such as wastewater from professional car washes, landfill leachate and stormwater. This mixture is very attractive, since it is a low-cost material which has a capability to simultaneously remove inorganic as well as organic pollutants. Since any filter material eventually needs to be replaced either due to saturation of pollutants or reduced infiltration capacity, it is important that the residual can be handled at low cost and that the environment will be not impaired. The tested mixture, used in filter beds, showed low leaching values and high simultaneous removal efficiency of metals as Cu, Cd and Pb, non-polar organic compounds such as PCBs. Polar organic compounds as phenols were also efficiently removed by microbial and/or chemical degradation in the studied treatment plants with the filter bed acted as a biofilter. Filter material used for three years in a full-scale plant for leachate treatment and four years in treatment plants for wastewater from car washes, had sufficiently high energy content indicating that energy recovery is a good alternative for handling after its usage. Results show that the presented filter material is excellent for both small scale applications (e.g. treatment systems for car wash wastewater with capacity between 250 - 3000 m³ per year) as well as large-scale applications (e.g. filter systems for landfill leachates with capacity above 30,000 m³ per year).