Presence and fate of priority substances in domestic greywater treatment and reuse systems

A wide range of household sources may potentially contribute to contaminant loads in domestic greywater. The ability of greywater treatment systems to act as emission control barriers for household micropollutants, thereby providing environmental benefits in addition to potable water savings, have not been fully explored. This paper investigates the sources, presence and potential fate of a selection of xenobiotic micropollutants in on-site greywater treatment systems. All of the investigated compounds are listed under the European Water Framework Directive as either "Priority Substances" (PS) or "Priority Hazardous Substances" (PHS). Significant knowledge gaps are identified. A wide range of potential treatment trains are available for greywater treatment and reuse but treatment efficiency data for priority substances and other micropollutants is very limited. Geochemical modelling indicates that PS/PHS removal during treatment is likely to be predominantly due to sludge/solid phase adsorption, with only minor contributions to the water phase. Many PS/PHS are resistant to biodegradation and as the majority of automated greywater treatment plants periodically discharge sludge to the municipal sewerage system, greywater treatment is unlikely to act as a comprehensive PS/PHS emission barrier. Hence, it is important to ensure that other source control options (e.g. eco-labeling, substance substitution, and regulatory controls) for household items continue to be pursued, in order that PS/PHS emissions from these sources are effectively reduced and/or phased out as required under the demands of the European Water Framework Directive

Emission control strategies for short-chain chloroparaffins in two semi-hypothetical case cities

The short-chain chloroparaffins (SCCP), (C10-13 chloroalkanes) are identified in the European Water Framework Directive, as priority hazardous substances. Within the ScorePP project, the aim is to develop emission control strategies that can be employed to reduce emissions from urban areas into receiving waters. Six different scenarios for mitigating SCCP emissions in two different semi-hypothetical case cities representing eastern inland and northern coastal conditions have been evaluated. The analysis, associated with scenario uncertainty, indicates that the EU legislation, Best Available Technologies (BAT) and stormwater/CSO management were the most favorable in reducing emissions into the environment

Source control options for reducing emission of priority pollutants from urban areas.

The overall aim of the ScorePP project is to develop comprehensive and appropriate source control strategies that authorities, cities, water utilities and the chemical industry can employ to reduce emissions of priority pollutants (PPs) from urban areas into the receiving water environment. Focus is on the 33 priority and priority hazardous substances and substance groups identified in the European Water Framework Directive. However, this list may be expanded to include emerging pollutants or reduced if appropriate model compounds can be identified. The initial work focuses on 67 substances, including substances identified in the proposed European environmental quality standard (EQS) directive as well as the defined example compounds and several organometallic derivatives. Information on inherent properties, environmental presence and fate, and legislative issues is made available in open database format, and a data management system combining chemical identification (CAS#), NACE economic activity classifications and NOSE-P emission source classifications has been developed as a basis for spatial characterisation of PP sources using GIS. Further work will focus on dynamic urban scale source-flux models, identifying emission patterns and optimising monitoring programmes in case studies and multi-criteria comparison of source control versus end-of-pipe mitigation options in relation to their economic, social and environmental impacts

Assessment of the removal potentials of selected EU Water Framework Directive priority pollutants within stormwater Best Management Practices.

An objective of the multi-disciplinary EU Framework 6 project ScorePP (Source Control Options for Reducing Emissions of Priority Pollutants) is the identification and assessment of appropriate emission control technologies to limit the release of priority pollutants (as identified by the EU Water Framework Directive (WFD)) to receiving waters. This paper focuses on stormwater as the source of these pollutants and provides an assessment of the ability of stormwater Best Management Practices (BMPs) to remove a selected range of WFD priority pollutants. In the absence of field data on the removal of many of the WFD priority pollutants by BMPs, a pragmatic approach involving available information is presented to support stormwater practitioners in this area. The systematic unit operating approach for assessing the comparative pollutant removal potentials of different types of BMPs originally described by Scholes et al., (2005) has been further developed and applied to 8 organic compounds, 3 organometallic compounds and 2 metals. The results of the application of this approach are presented and discussed, and a proposal describing the support this approach can contribute to the wider BMP-selection process is developed

Identifying and classifying the sources and uses of xenobiotics in urban environments

The sources and uses of xenobiotics in urban environments are very diverse, making structured approaches to source and use classification a fundamental requirement for effective pollution management. This chapter provides a general introduction to the topic of substance source and use identification, highlighting the key differences between different types of sources (e.g. processes vs. commodities; natural vs. anthropogenic etc.) and different types of uses (e.g. active vs. passive; dispersive vs. non-dispersive, etc.). Examples of relevant classification systems and their applications are also given, and the diversity of potential xenobiotic sources and uses is clearly demonstrated through the description of a series of ‘archetypes’ (i.e. model examples). The chapter concludes with an overview of useful source tracking approaches (e.g. database mining, marketing surveys, forensic approaches etc.)

Presence and fate of priority substance dynamics in domestic greywater treatment and reuse systems.

A vast number of household sources may potentially contribute to greywater contaminant loads. This paper investigates the sources, presence and potential fate of a selection of xenobiotic organic compounds (listed under the European Water Framework Directive as ‘Priority Substances’) in onsite greywater treatment systems. Significant knowledge gaps are identified. A wide range of potential treatment trains are available for greywater treatment and reuse but information regarding the treatment efficiency of priority substances in these systems is almost wholly lacking. Geochemical modelling indicates that priority substance removal during treatment is likely to be predominantly due to sludge/ solid phase adsorption. Since the majority of automated greywater treatment plants periodically discharge sludge to sewers, most systems are likely to be of limited benefit in terms of overall source control. Hence, it is important to ensure that other source control options (e.g. green labeling, green procurement, information campaigns, substance substitution, and regulatory controls) continue to be pursued, in order that greywater recycling can continue to reduce the burden on potable water supplies without presenting further risks to the environment

Emission control strategies for short-chain chloroparaffins in two semi-hypothetical case cities

The short-chain chloroparaffins (SCCP), (C10-13 chloroalkanes) are identified in the European Water Framework Directive, as priority hazardous substances. Within the ScorePP project, the aim is to develop emission control strategies that can be employed to reduce emissions from urban areas into receiving waters. Six different scenarios for mitigating SCCP emissions in two different semi-hypothetical case cities representing eastern inland and northern coastal conditions have been evaluated. The analysis, associated with scenario uncertainty, indicates that the EU legislation, Best Available Technologies (BAT) and stormwater/CSO management were the most favorable in reducing emissions into the environment