VDM Bloor, M: Aquatic Pollution

A standardised environmental assessment and pollution control methodology was developed to monitor and reduce the impact of leachate discharge on its receiving waters. A landfill site in South Wales, U.K. was used as a case study for the investigation. Application of a biological stream survey identified that the leachate caused localised pollution of the associated waterway. An in-situ and ex-situ toxicity testing programme was undertaken using Gammarus pulex and Asellus aquaticus macro- invertebrates to establish pollution boundaries. It was revealed that the leachate held acute and sub- lethal toxicity to both test species. The treatability of the leachate with respect to removal of the environmentally toxic component(s) then was assessed by aerobic digestion, air stripping and reed bed technologies. Of the three applied techniques, air stripping would best protect the integrity of the connecting waterway. However, health issues need to be taken into consideration when stripping a leachate that contains substance(s) with such obvious properties of toxicity as such, it would be inappropriate to rely on known fail-safe systems.