Hexachlorocyclohexane (HCH) isomers, their impurities and transformation products are a serious and persistent environmental problem at many sites. Studies suggest that HCH production across Europe has led to some 40 mega-sites with total HCH waste exceeding 250 000 tonnes. This is in addition to many smaller sites and diffuse contamination problems. Many EU projects have considered HCH source zone elimination technologies and associated groundwater bioremediation. However, as yet these have not yielded practical deployable techniques at reasonable cost. Excavation and removal to hazardous landfill or off-site treatment have been practical interventions at mega-sites. However, these carry major costs which cannot be met for the majority of sites. More commonly, mega-sites have been dealt with by using containment with impermeable barriers. This containment is never perfect, though, and the leakage of HCH and its transformation products, and subsequent drainage to surface water or groundwater, remains a potential cause of significant harm. As HCH bioaccumulates in freshwater food chains (e.g. fish, crustaceans), and can enter biomass of plants and broadleaf trees, the potential for cumulative chronic harm in the long term is high. Treatment of these leakages can be costly using conventional wastewater treatment plants (WWTPs).
LIFEPOPWATs goal is to provide a method of mitigating risks to water from HCH mega-sites, the most intractable ongoing HCH problem. It aims to offer a more robust, low-maintenance and sustainable treatment that is cheaper than conventional WWTPs and can be deployed in remote locations where access to infrastructure may be limited. The treatment is based on integrated reactive zones with wetland as a polishing step (Wetland+). The wetland component also has benefits for biodiversity improvement, local climate protection, landscape water storage maintenance and aesthetic functions. LIFEPOPWAT will benchmark Wetland+s performance, ease of deployment and sustainability against conventional approaches. The technique can also be scaled down for smaller problem sites.
The project will contribute to implementation of Directive 2013/39/EU concerning water policy priorities and the Stockholm Convention on Persistent Organic Pollutants (POPs). It will establish the steps to stop uncontrolled leaking of POPs via water into the environment and so help reduce these risks. Its impacts are also closely linked to EU energy, climate change and environment policy, as well as other areas, such as food, farming, fisheries, and regional and urban development. Use of engineered wetlands is in line with the EU Water Framework Directives objectives on restoration of aquatic ecosystems.
The specific objectives include: