PROJECT DESCRIPTION
BACKGROUND
Hexachlorocyclohexane (HCH) isomers, their impurities and transformation products are a serious and persistent environmental problem for many sites. Studies suggest that HCH production across Europe has led to some 40 mega-sites with total HCH waste exceeding 250 000 tonnes. Moreover, many smaller sites and diffuse contamination problems are a pressing issue. Many EU projects have considered HCH source zone elimination technologies and associated groundwater bioremediation. However, these have yet to yield practical techniques to deploy at a reasonable cost. Excavation and disposal of waste in hazardous landfills or off-site treatment have been practical interventions at mega-sites. However, these carry major costs which cannot be met for most sites. More commonly, mega-sites have been dealt with by containment with impermeable barriers. This containment is never perfect, though, and leakage of HCH and its transformation products, with 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 expensive using conventional wastewater treatment plants (WWTPs).
OBJECTIVES
LIFEPOPWAT’s goal was to provide a method of mitigating risks for water from HCH mega-sites. It aimed at offering a more robust, low-maintenance and sustainable treatment that is cheaper than conventional WWTPs and that can be deployed in remote locations where access to infrastructure may be limited. The treatment was based on integrated reactive zones with wetland as a polishing step (Wetland+). The wetland component also had benefits for biodiversity improvement, local climate protection, landscape water storage maintenance and also had aesthetic functions. LIFEPOPWAT conducted a benchmark analysis on Wetland+ performances, easing its deployment and measuring its sustainability against conventional approaches. The technique was also scaled down for smaller problematic sites.
The project contributed to implementation of Directive 2013/39/EU concerning water policy priorities and the Stockholm Convention on Persistent Organic Pollutants (POPs). It established key steps to stop uncontrolled leaking of POPs via water into the environment, and so helped reduce these risks. Its impacts were 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 was in line with the EU Water Framework Directives objectives on restoration of aquatic ecosystems.
RESULTS
The main objective of the project - to provide means of mitigating risks to water from HCH mega-sites using Wetland+ technology, and the means for successful replication in other sites - has been reached, including positive outcomes from benchmarking with conventional approaches (WWTP).
Specific objectives that were reached include:
- the introduction of a large-scale pilot Wetland+ prototype at Hajek (CZ), with subsequent confirmation from monitoring of high efficiency of removal of targeted contaminants (HCH, ClB, ClPh).
- demonstrations of site specific replication pathways to other sites starting from a field pilot deployment prototype at Jaworzno (PL), considering differences in contamination, hydrogeology, microbial communities, and local resources across the different stages of Wetland+ system (abiotic redox, sorbent systems, biodegradation and wetland).
- the development of a specific replication process, with over 30 candidate sites for replication identified and assessed. The most promising sites are Pais Basco/Jata landfill and Aragon/Sabinanigo in Spain, and Libis in the Czech Republic.
- innovations in performance monitoring to improve replication and reduce management costs. Several routes to green monitoring and analysis were explored (in total, 1,896 samples of diverse matrices were analysed).
- enhanced optimisation of the Wetland+ process, including the Life Cycle Assessment (in comparison with conventional WWTP) or the Technology Guide.
- targeted communication and dissemination of the outcomes to reach diverse audiences and interest groups on a global basis, but particularly within Europe.
Key results reached encompassed:
- reduction of HCH in stream water. At the largest site P1 in Hajek, the HCH mass discharge into the Ostrovsky Creek after the Wetland+® system implementation decreased from 23–25 g/day to 0.3–11.3 g/day (51 % - 99 % decrease). In the 27 months of testing operations, 131 000 m3 of water were treated, and about 12.8 kg of HCH, 68.5 kg of ClB and 1.2 kg of ClPh were removed;
- increased biodiversity around Hajek on the 0.5 ha P1 wetland over the current status (number of plant species increased from 48 to 62 between 2022 and 2023);
- the creation and dissemination of a Technology Guide to support future design and decision-making at other sites;
- the identification of over 30 candidates for replicability sites, with more detailed research completed at the 3 most promising sites (2 in Spain and 1 in the Czech Republic);
- 2 083 visits on the project website;
- 2 articles in high impact journals (and 3 more articles in a peer-review process);
- participation of the project team in over 50 expert events (with approximately 6 000 participants);
- presentation of the project on radio (6 times) and TV broadcasting (3 times) in the Czech Republic;
- creation of leaflets in three languages (in EN, CZ, PL, in 2,050 copies in total);
- production of a special video.
Policy links:
The project contributes to the implementation of Directive 2013/39/EU of the European Parliament and of the Council of the European Union supplementing Directive 2000/60/EC and 2008/105/EC concerning water policy priorities and the Stockholm Convention on Persistent Organic Pollutants. It proposed solutions to stop uncontrolled leaking of POPs via the water path into the environment with an eye to reducing risks. The project’s impacts are also closely linked to the EU Energy, climate change and environment policy, and to other policies in related fields, such as, e.g., in food, farming, fisheries, or regional and urban development. Use of engineered wetlands is in line with the objectives laid out in the Water Framework Directive on restoration of aquatic ecosystems.
