The list of priority substances for which environmental quality standards were set in 2008 has been recently modified, increasing the number of substances or groups of substances from 33 to 45 (DIRECTIVE 2013/39/EU). New monitoring methods as passive sampling and other instruments have a promising future application for detection and quantification of micropollutants not yet regulated. Scientific community and water operators go one step forward finding innovative solutions for the elimination of these undesirable substances in water depuration and purification processes.
In this context, the 7th Framework Programme European co-funded DEMEAU project means a unique opportunity to demonstrate how conventional and alternative water treatment processes can deal with the emerging pollutants elimination in drinking water processes and anthropogenic-impacted environments. Managed Aquifer Recharge (MAR) is one of the four promising technologies evaluated in DEMEAU. First output available include a complete European MAR catalogue with the characterisation of more than 300 MAR sites. The catalogue shows how MAR is widely spread in 23 European countries.
The demonstrative phase of the project includes the analysis of selected emerging pollutants in a simulated MAR system fed with reclaimed water. The selection of the target compounds has been made according to the following criteria: (i) presence in wastewater and drinking water supplies, (ii) environmental relevance; (iii) chemical and physical properties and (iv) existence of analytical method/s for their quantification.
The objective of this work is to present the results of the demonstration phase of DEMEAU project concerning the simulation of a MAR system using reclaimed water in aerobic and anaerobic conditions. Therefore, the evaluation of the elimination potential of emerging compounds by Soil Aquifer Treatment (SAT) is presented. Aerobic and anaerobic conditions have been selected because they are known be significant for emerging pollutants abatement in MAR facilities (Heberer et al. 2008).
The Waste Water Treatment Plant (WWTP) of El Prat del Llobregat has been selected for the operation of two experimental columns simulating the process of aquifer recharge with (i) direct water from the secondary treatment of the plant (anaerobic conditions) and (ii) water after 10-15 days aeration (aerobic conditions). Water injected from the secondary effluent has a high concentration in ammonia and a low dissolved oxygen content.
Columns are made of stainless steel (1.50 meters high and 0.50 meters of inner diameter) and have been operated at a residence time of about 2 months. The filling material is constituted by homogeneous sand grains enriched with 1% of organic matter, simulating the natural conditions of an alluvial aquifer (Barbieri et al. 2011). Emerging pollutants are naturally present in the effluent of the secondary treatment of the WWTP selected at different concentrations in the range of micrograms/L and nanograms/L (see Table 1, Teijon et al., 2010). pH, redox potential, dissolved oxygen, total organic carbon, turbidity and major ions (NO3-, NO2-, NH4+, SO42-) have been analysed regularly in recharge water and output water to monitor MAR process response. The analysis of the behaviour of 11 selected emerging compounds along the experiment has been also carried out.
The results shown geochemical changes occurring along the recharge period and their relation with emerging micropollutants removal. Results obtained in the experimental phase have been used to feed a toolbox to help new MAR facilities implement and operate successfully under different field conditions. Specifically in Spain, results are useful for the start-up of the deep injection system located in the area of the Vall d’Uxó (Castellon), in the Mediterranean coast.
References
Barbieri, M., Carrera, J., Sanchez-Vila, X., Ayora, C., Cama J., Köck-Schulmeyer, M., López de Alda, M., Barceló, D., Tobella Brunet, J., Hernández García, M (2011). Microcosm experiments to control anaerobic redox conditions when studying the fate of organic micropollutants in aquifer material. Journal of Contaminant Hydrology 126 (2011) 330–345.
DIRECTIVE 2013/39/EU of the European Parliament and of the Council of 12 August 2013 amending Directives 2000/60/EC and 2008/105/EC as regards priority substances in the field of water policy. Official Journal of the European Union. 24.8.2013.
Heberer, T.; Massmann, G.; Franck, B.; Taute, T. and Dünnbier, U. (2008). Behaviour and redox sensitivity of antimicrobial residues during bank filtration. Chemosphere 73, 451–460.
Teijon, G., Candela, L., Tamoh, K., Molina-Díaz, A., Fernández-Alba, A. R. (2010). Occurrence of emerging contaminants, priority substances (2008/105/CE) and heavy metals in treated wastewater and Groundwater at Depurbaix facility (Barcelona, Spain). Science of the Total Environment 408 (2010) 3584-3595.
1. Introduction
Contamination of drinking water resources is becoming a threat that is particularly widespread. Nowadays even in European countries clean drinking water is at risk. Pharmaceuticals, pesticides and other micropollutants are emerging substances in surface and groundwater causing contamination of drinking water resources and ultimately to closing down groundwater abstraction wells.
2. Background
Pesticides and other micropollutants in groundwater and surface water are more and more present in very low concentrations, in the nanogram to microgram per litre range. Concentrations already exceed the EU limit value for pesticides (or other micropollutants) in drinking water recourses. Closure of the groundwater abstraction wells or the entailing treatment is costly. It is important to find a sustainable and cost-effective remediation technique since it remains unknown if there are long term cumulative dose-additive or synergistic effects of low concentrations of substances occurring as a mixture. Knowledge of degradation processes at such low concentrations is limited and novel approaches are needed to develop biological treatment technologies that are efficient at these low concentrations.
BIOTREAT is a European project in which urgently needed sustainable biotechnologies are developed for remediation of drinking water resources contaminated with micropollutants such as pesticides and pharmaceuticals and their metabolites.
The basis of the technologies is bioaugmentation, which in this case is the introduction of specific degrading microorganisms or microbial consortia into existing sand filters at waterworks or mobile filters placed close to the (groundwater) abstraction well.
The compound BAM (2,6 Dichlorobenzamide) has been chosen as model compound for metabolic biological degradation. BAM is a metabolite of the broadly used herbicide dichlorobenzonitrile or dichlobenil. The bacterium Aminobacter sp. MSH1 is found to be capable to mineralize BAM.
A strategy using metabolic degradation pathways was used to target water-pollution cases where metabolically degrading bacteria are available. In order to simulate drinking water production at waterworks we have up scaled the lab-scale batch experiments to a sand filter column experiment in our lab and finally to a medium scale sand filter column that is used as experimental column at a drinking water well. The BAM mineralizing bacterium was found capable to degrade the metabolite in batch culture and sandfilter column experiments at low concentrations. Pilot scale sand columns have been designed based on these results. A Life Cycle Analyses (LCA) and a cost benefit analyses (CBA) have been performed in order to gain insight in the sustainability and cost effectiveness of the developed technologies. Based on the technical results, the LCA and the CBA actions plans for implementation of the developed technologies could be made.
3. Biotreat partners
GEUS, DTU, University Leuven, EAWAG, University Gent, Bundesanstalt für Gewässerkunde, Avecom, LCA 2.0, Bioclear
After more than 20 years´ work and an expenditure of some 160 million euros the remediation project regarding the site of a former explosives production plant is nearing completion. During the remediation, thanks to a close cooperation with all relevant stakeholders during planning and implementation, the drinking water production was able to be continued without any interruption. The remediation will ensure a long-term future utilization of the site for housing and industrial and commercial purposes, as well as drinking water production.
The production of explosives from 1939 to 1945 and the subsequent improper closedown of the plant after the end of the war caused that considerable amounts of contaminants (in particular nitroaromatic compounds e.g. TNT) were released into the environment. Despite this pollution, the location has evolved into a place to live and work, which is important for the region. Today some 8,000 people live and work on the former site. The domestic drinking water and industrial water supply has been covered by the Stadtallendorf waterworks with an annual resource of approx. 10 million m³. All activities made use of the existing infrastructure of the former explosives production plant (buildings, roads, pipes, wells and treatment facilities).
In the 1980s investigations carried out at the site made it clear that the soil and groundwater pollution was a serious threat, as far as the further utilization and the environment in general was concerned. This caused a major uncertainty among the local population, going as far as debates as to whether the location should be completely abandoned.
In view of the intensive utilization of the site a risk management concept for the remediation was developed in consultation with all stakeholders. This was devised to safeguard the various types of land use of the site on a long-term and sustainable basis, both during and after the remediation, and ensure a relevant reduction of contaminants. The safety of the supply of drinking water was a key target of the remediation work which, once the contamination of soil and groundwater had been established, became the main priority.
Apart from the utilization-based soil remediation, which in the hot spots (as a general rule up to a depth of 3 metres) involved the removal of approx. 150 tonnes of nitroaromatic compounds, the concept also provided for hydraulic measures. Since 1995 this has prevented contaminated groundwater from flowing into the drinking water wells. The water extracted (approx. 450,000 m³/a) is processed in a two-line water treatment system (activated carbon). The output volume of the extraction and the pumping rates of the drinking water production are synchronized.
The hydraulic measures undergo meticulous monitoring measures. All stakeholders have access to the data collected via an internet-based information system. Within a project of the German KORA research network a model has been developed to assess the impact of interventions in the hydraulic system.
The remediation of the site will not be finalized with the completion of the soil remediation. The remaining contaminants in the soil make it necessary for the hydraulic measures to continue in operation and that there is a controlled approach dealing with the soil in the course of any building projects.
Therefore, the remediation phase will be followed by an indefinite period after-care phase which will involve follow-up work regarding the soil, hydraulic measures, contract and project management plus data and knowledge management.
Alongside the technical measures, hydro-geological and geological bases and natural attenuation processes, as well as operational experience, the paper addresses in particular the cooperative process of developing targets and measures with the various stakeholders involved, which of course includes the necessary communication throughout the entire process. The requirements for long-term data and knowledge management will also be illustrated, and the tools used outlined.
Perfluorinated compounds (PFCs) are a large class of synthetic fluorine-containing chemicals that is receiving increased attention by government agencies and land owners in the United States (U.S.). The structure of PFCs consists of a fluorinated carbon chain, with a varying number of carbon atoms, and a charged functional group such as a sulfonic or carboxylic acid. PFCs historically have been used in a variety of industrial and consumer applications and products, including coatings, aviation hydraulic fluids, fire-fighting foams; household care products (including paints, adhesives, waxes and polishes); water, stain, and grease repellant coatings on textiles, leather, and carpet. The two PFCs with the largest historical production and use in the U.S. are perfluoroctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). Production of PFOS by its largest U.S. manufacturer in the ended in 2002, and worldwide production of PFOA and analogous PFCs currently is being phased out.
PFCs have extremely high structural high stability due to the strength of their carbon-fluorine bonds. This attribute causes PFCs to be chemically inert, maintain stability at high temperature, resist degradation in the environment, have low volatility, and bioaccumulate in animals. In addition, PFCs tend to have a much higher aqueous solubility and low sorption affinity compared to highly chlorinated pollutants of concern, such as polychlorinated biphenyls and dioxins. The U.S. Environmental Protection Agency (EPA) Science Advisory Board has characterized PFOA as a likely human carcinogen; however, the U.S. EPA has not yet issued regulatory criteria for PFCs in drinking water. Instead, U.S. EPA has issued Provisional Health Advisory (PHA levels), which are drinking water concentrations that are not known to cause adverse health effects from short-term consumption. The U.S. EPA PHA levels for PFOA and PFOS are 0.4 ug/L, and 0.2 ug/L, respectively. Certain State government agencies in the U.S. have specified drinking water criteria that are different than the U.S EPA PHA levels; Minnesota, for example, has set health risk limit levels for PFOA and PFOS of 0.3 ug/L each, and New Jersey has established a preliminary drinking water guidance value for PFOA of 0.04 ug/L.
Understanding of the environmental occurrence and distribution of PFCs in the U.S. is still in its infancy, similar to understanding of the occurrence of perchlorate and 1,4-dioxane in the U.S. 15 years ago. Because the analytical methods for quantifying PFCs in groundwater and drinking water samples, which typically involve high pressure liquid chromatography in combination with mass spectrometry (HPLC/MS), are not routinely used in the analysis of aqueous samples, PFCs in environmental media have gone undetected in a majority of cases. However, a growing body of data suggest that, the more that proper HPLC/MS methods are used to screen environmental samples for PFCs, the more that they are detected at U.S. sites. For example, detection of PFCs in soil and groundwater at fire-fighting training areas in the U.S. has increased significantly. The U.S. Department of Defense (DoD) has estimated that up to 600 DoD sites have been used for fire-fighting or crash training and therefore are potential candidates for PFC contamination.
Due to the stability of their carbon-fluorine bonds, PFCs resist many conventional in situ treatment technologies. Ex situ treatment options including reverse osmosis and filtration through granular activated carbon have been shown to treat PFOS and PFOA successfully. Results of recent research suggest that less expensive treatment alternatives for treatment of PFOS and PFOA in groundwater are on the horizon, including ultrasonic irradiation (sonochemical degradation), and in situ chemical oxidation using heat-activated persulfate and permanganate. Clearly, there is need for private and public sector stakeholders around the world to develop and commercialize more cost-effective methods for treating PFOA and PFOS.
This presentation will provide a state-of-the-science overview of historical usage, toxicity, environmental occurrence, environmental fate and transport, and treatment methods for PFCs, as well as current U.S. EPA and State government regulations regarding PFCs.
Bottom-up regional initiatives to tighten up the generic pesticides rules and regulations in the Netherlands
Cors van den Brink@ (RHDHV), Carolien Steinweg (RHDHV) and Anton Dries (Province of Drenthe)
@corresponding author: cors.van.den.brink@rhdhv.com
Abstract
The presence of pesticides in groundwater and surface water in the Northern part of the Netherlands provides a threat for the sustainable drinking water supply. In addition the objectives of the Water Framework Directive may not be met in time. During the last decades various projects have been defined by several stakeholders to study this problem. And also to reduce the risk of pesticides by informing land-users and citizens by (financially) supporting land use management aiming a reduction of the risks by the use of pesticides. However, a comprehensive overview of the presence of pesticides in groundwater and surface water carried out in 2011 showed that WFD-limits were exceeded in approximately 28% of the monitoring wells. To be able to identify and implement effective measures with the appropriate stakeholders, the use and risks of the pesticides were established in the Northern part of the Netherlands.
The analysis of the use and risks of pesticides consists of i) analysis of the actual concentrations of pesticides in groundwater and surface water measured with the regular monitoring networks of the provinces and water boards ii) analysis of the spatial distribution of pesticides in groundwater and surface water, and iii) evaluation of the success factors of initiatives in and outside the region.
The evaluation of the monitoring sites of groundwater and surface water showed that pesticides provide a risk for the groundwater quality in the sandy areas. In areas with more heavy soil types such as clay and peat, the risks of the use of pesticides shift from groundwater towards surface water.
The spatial distributions were calculated based on agricultural and non-agricultural pesticide application reported by regional experts in 1997 and 2010, combined with the land use, soil type, and pesticide characteristics. The measured and calculated risks were corresponding for 70% of the monitoring sites. From the distributions of 1997 and 2010 it was concluded that the risk has been reduced with 80 – 90% for both agricultural and non-agricultural use of pesticides. Nonetheless, the risks are still too high in specific areas and for specific crops. The stakeholders accepted the pesticide-application figures because these figures were provided by regional experts. They also concluded that the instrument could be used to define and evaluate scenario’s aiming at a reduction of the risk of pesticides in the second step of the study.
The second step consisted of i) the selection of top-10 pesticides in groundwater and surface water, ii) the set-up of an analysis framework to define the major focus on reducing risks for each top-10 pesticide, and iii) identification of effective measures together with the stakeholders.
This study shows that combining various points of view, data sources, and stakeholders together with administrations made it possible to make a comprehensive overview of the use and risk of pesticides in the Northern part of the Netherlands. The role and knowledge of regional experts was important for the acceptance of the results calculated with these data. Tools used to structure, quantify and visualise the relevant data and collective understanding were necessary to provide an informed basis for the dialogue, exploration and decision-making in both phases of the study. However, this analysis also showed that even the use of approved pesticides in an approved way and moment of application will result in exceedance of the WFD-limits.
In addition, a detailed analysis of the top-10 pesticides showed, that the risk of the pesticides measured in groundwater and surface water could not be explained and the risks of environmental friendly alternatives were in the same order as the top-10 pesticides. The main results of the study showed that:
- A comprehensive overview of the use and risks of pesticides is carried out and accepted by all stakeholders involved;
- Regional measures will not be effective within the generic rules and regulation because:
o Actual risks result from approved pesticides applied in an appropriate way;
o Adequate instruments to identify and stimulate environmental friendly alternatives are lacking
The tightening up of the generic rules and regulations is therefore the only feasible way to reduce the risks of pesticides. Two tracks have been developed i) based on the results of the analysis, a position paper signed by the authorities of the Northern part of the Netherlands has been sent to the Dutch ministry of Infrastructure and Environment and ii) the monitoring data are used to evaluate the official national approval procedure by the Dutch Board for the Authorisation of Plant Protection Products and Biocides.
As result of the position paper, the issue is ‘on the agenda’ and is discussed in the appropriate fora. In addition, the evaluation of the national approval procedure has resulted in an ongoing and constructive discussion with the Board for the Authorisation of Plant Protection Products and Biocides which might result in changes in the authorisation of riskful pesticides.