Development of integrated water reuse strategies

Recurring droughts throughout the last decades have revealed that water supply is often insufficiently balanced to the demand and thus vulnerable to extreme climatic events and structural or seasonal demand peaks. In the context of a more sustainable water management, water reclamation and reuse appears to be an alternative dependable water resource. This paper, which was worked out in the frame of the AQUAREC project aims to develop a water reuse strategy based on the anticipation of major factors that promote or slow down the development of water reuse. The investigations distinguish between substantial issues related to the measurable variables of water management such as water availability and demand and the analysis of normative issues as laid down in legislation, guidelines and reflected by the institutional settings. Moreover, water reuse particularly faces the challenge to comply with the precautionary principle and affords a robust risk management to adequately response to the objections of the public. In this context the importance of establishing a best management practice framework and increasing public awareness of the water cycle have to be emphasised as two important aspects in strategic planning of water reuse. A range of supportive measures is recommended to fix water reuse in integrated water management and to recognise its beneficial effects. Different policy options and opportunities to achieve this are discussed.

Wastewater is commonly reused, although mostly unintended. Once discharged to the aquatic environment, wastewater treatment plants effluents are recycled to the “natural” water flows from which it is withdrawn again for human purposes. It is important to acknowledge this fact when developing a water reuse strategy. It means addressing a factual issue many people might not be aware of thus far. Hence the importance of involving the public may not be underestimated. It might be beneficial to base the intention on a clear explanation of why reuse is a proposed solution. Evidence for both, drivers for reuse and its beneficial effects, should be communicated. Strategic water reuse shall in any case comprise a characterisation of the individual situation in terms of physical boundary conditions in view of aggravated uncertainty of water availability in future. The definition of a reuse goal is essential, too. A reuse strategy has to address different target groups at different levels. It has to enable authorities to guide the licensing procedure of schemes and it should encourage operators to embark on intensified reuse practice while supporting a sound funding opportunity. This can be accomplished rather in a frame of full-cost recovery prices. The controversial discussion about reuse guidelines in the last years has revealed the problematic approach to establish limits whose determination is always based on incomplete information. Shared goals might be rather the aim than simple compliance with a list of threshold values. The agreement of these goals should be grounded on the value based decision of the community which might be a true output of a public participative process [16]. Multi-barrier risk management approaches might fit into this line of reasoning. Cost arguments are a major impediment for tapping reclaimed water. Additional invest and running costs for upgrading and distribution of reclaimed water often reduce its competitiveness against conventional water. This would demand a re-evaluation of water and finally an economic anticipation of the potential environmental benefits of wastewater reuse. But, as the WFD acknowledges, a level of environmental quality — the good status of water — shall be preserved for reasons of precaution, irrespective of its net present economic benefit [16]. It will also be necessary to bundle the efforts undertaken to date by institutions in different EU countries in the field of reuse development and implementation to shape them into a European reuse strategy. The review of the Environmental Technologies Action Plans [17] suggest (although not explicitly referring to water reuse) an implementation strategy that builds on the experiences and initiatives in member states. It is intended to draw from experiences made on member state level in identifying best practices to set up a consolidated roadmap at EU level. The approach to a European wide promotion of reuse could be designed similarly. With reference to water reuse the experiences gained in Spain and other EU countries with a variety of reuse schemes of different technological design constitute a valuable basis for contemplating such a roadmap for the reuse sector. Moreover experiences from around the world where reuse is a common consideration in integrated water management (USA, Israel, Australia) should be taken into account.