One day with different formats to exchange on combined natural engineered treatment processes.
The day started off with a key note by Stefan Uhlenbrook of the United Nations World Water Assessment Programme. He made aware of the still huge challenge of achieving the Sustainable Development Goal #6 of "Clean Water and Sanitation". He also pointed out how nature-based solution can help to leave no one behind.
Thomas Wintgens, AquaNES Coordinator, further developed these ideas and related them to the AquaNES project approach. His talk exemplified how cNES could be a sustainable response to water treatment and water management challenges.
Lectures on AquaNES outcome pointed out how to transfer results from research to practice. Two cases highlighted wastewater treatment combinations able of considerably reducing the organic micropollutants and bacterial load discharged to surface waters. Regina Gnirss of Berliner Wasserbetriebe reported on the experiences using ozone and different natural or engineered filters as an advanced treatment stage. The vast operational experience gathered during the project was fed into the design of the full-scale ozonation plant.
Andrea Brunsch of Erftverband summarized the results of long-term piloting of a so-called retention soil filter plus (RSFplus)This amended type of RSF for flexible use as post-treatment during dry weather flows and for combined sewer overflow. The concept is currently being realized in full-scale at the WWTP Rheinbach
Axel Aurouet of Geohyd Antea presented the ICT tool their developed for a managed aquifer recharge site in France. The challenge there is to optimally operate the system as to provide sufficient water of adequate quality for golf course irrigation. The solution is a platform in which online and offline monitoring data are combined with a hydrological model of the site
Heather Smith from Cranfield University highlighted aspects of public receptivity and governance structures, which might either be barriers or supportive to the implementation of combined natural engineered treatments. The findings of her study triggered questions about which disciplines to involve and which approaches to follow to better raise awareness in the society for such systems and their benefits.
The all-day Gallery Tour offered opportunity for face-to-face discussions. This was actively used by participants to engage themselves in the AquaNES topics and for lively exchange.
In the afternoon six workshops were dedicated to particular aspects of AquaNES demonstration cases. The audience was invited to reflect on findings and to share their own experience.
The panel discussion summarized the day.
It was acknowledged that climate uncertainties require some sort of adaptation. cNES are supposed to be no-regret solutions. The panelists viewed the opportunities for cNES.
They confirmed existing practice and future potential, which certainly lies in small-scale systems and periurban area, when it comes to wastewater treatment. But it is also worth considering fast growing urban areas and new development for the application of decentral solutions. This would open at the same time the opportunity to reconcile several objectives, such as water storage capacity, greening infrastructure or other more social and community needs.
The cNES concept is also suited to improve long-established schemes, such a bankfiltration sites. Water utilities from the project testified that the project helped in identifying how to extend the production capacity and to make up for shortcomings while preserving the cost and treatment advantages of bankfiltration.
A particular challenge remains to identify what can be transferred and what requires adaptation to local conditions. In this respect learning from each other and expert exchange are vital elements for successful implementation: an aspect to be taken into account when trying to match user needs and cNES solutions.
Role of policy
It was stressed that it always requires a good motivation to establish any new solution. In the water sector, this is decisively driven by new or tightened regulatory frameworks. Next to such drivers also appropriate support in financing can be an aspect to tip the balance for cNES, as eventually it will all comes down to cost in decision making.
Openness of operators for demonstration is key in promoting cNES. And on the long run and for wider uptake of cNES also organisations and associations elaborating standards in water treatment will have to take on board these concepts, yet these are typically long processes.
The participants were confident that AquaNES has produced a promising range of evidence supporting this.