Innovative technology based on constructed wetlands for treatment of pesticide contaminated waters

PROJECT DESCRIPTION

BACKGROUND

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).

OBJECTIVES

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:

a large-scale pilot Wetland+ prototype at Hajek (Czech Republic), P1, based on completed R&D. Key performance attributes, costs and wider sustainability outcomes will be monitored. Process refinement to support scale up and replication;

a field pilot deployment prototype at Jaworzno (Poland), P2, to demonstrate site-specific replication pathway for other sites, taking into account differences such as contamination, hydrogeology, microbial communities and local resources across the different stages of Wetland+ (abiotic redox, sorbent systems, biodegradation and wetland);

a specific replication process a progression of candidate sites with several taken through to feasibility study stage, supported by targeted outreach to extend the potential for replication, and a business model to service replication needs;

innovations in performance monitoring to improve replication and reduce management costs. Several routes to green monitoring and analysis to be explored;

further optimisation of the Wetland+ process, by enhanced understanding of key stages, investigating the use of renewable energy and resources, developing process control strategies for remote locations, and optimisations for downsizing and potentially extending the range of treatable contaminants; and

targeted communication and dissemination of the outcomes to different audiences and interest groups on a global basis, but particularly within Europe.

 

RESULTS

Expected results:

reduced HCH in stream water. At the larger site in Hajek, a 99% reduction in total HCH isomers is targeted;

direct employment creation from P1 and P2 of three full-time equivalents;

increased biodiversity around Hajek by 50% on the 0.5 ha wetland;

production of a Technology Guide;

feasibility study for five candidate replication sites and a further 10 sites at earlier stages for replication; and

joint purpose vehicle linking the partners to provide replication services. Overall business volume to reach over 100 000 by year five and 3 million per year by year seven (three years after the project ends).