Wetland system for primary treatment of landfill leachate

A proprietary constructed wetland system has been developed as a long-term sustainable alternative for the treatment of high-nitrogen effluents such as landfill leachates. The system design is an enhancement of the microbiological processes that occur naturally in salt-marsh systems and extends the process capability of traditional vertical-flow constructed wetlands. Performance monitoring has demonstrated treatment rates of 69–95% per cell from a methanogenic landfill leachate influent containing 1400 mg/l ammoniacal-nitrogen at both pilot and laboratory scale. Two systems are currently being commissioned in the UK and applications for a further two systems are being considered by the UK Environment Agency.