The Watintech Project proposes the combination of different decentralised treatment approaches for sewage and urban run-off. The objective is to recover “on-demand” valuable products from these aqueous flows in a decentralized manner. The products to be recovered include water, energy (methane) and the generation of caustic and oxygen to avoid sewer corrosion and odours, all to be used locally.

Such a decentralized approach will also interact positively with centralized urban water infrastructure as local water storage capacity will alleviate pressure from peak flows of urban run-off in storm situations. Furthermore, decentralized solutions will enhance the life-time of centralized infrastructure delaying investments in sewer renewal and wastewater treatment upgrades.

The project is structured around 5 Work Packages (WP).

WP1. – Reclaimed water production from sewage and urban run-off. A combination of forward osmosis (FO) and reverse osmosis (RO) will be studied to generate concentrated wastewater and reclaimed water. Wetlands will be studied to treat urban run-off. The concentrated wastewater will be treated by anaerobic digestion (WP2 activity), whereby the resulting residual nutrient rich waste stream can be used to manage the wetland’s nutrient needs and water requirements, the latter being particularly useful during dry periods.

WP2.– Energy recovery via anaerobic digestion of FO concentrated wastewater in a membrane bioreactor. Sulphide inhibition of methanogenesis will be remediated by a novel approach coupling an electrochemical system to oxidise sulphide.

WP3.– Caustic soda and oxygen generation from sewage via electrochemical treatment and study of efficiency to manage sewer corrosion and odour by addition of these chemicals locally.

WP4.– Impact on centralised wastewater treatment. Optimization of nutrient removal at the centralized wastewater treatment under conditions of changed wastewater composition resulting from upstream decentralized treatment. A focus will be on energy efficiency and low direct greenhouse gas emissions.

WP5.– Modelling of novel processes and decision support system. Mathematical models will be developed and, jointly with economic, environmental, technical, and social criteria, will be used to construct a decision support system that allows designing decentralized system approaches and how their potentially multiple functions can be prioritized to yield the benefits most needed in a particular situation. Such a decision support system will also be useful to identify hot spots (e.g. of sewer corrosion) to place decentralized systems strategically instead of on an ad hoc basis.