A quality model for the circular economy of industrial water

RÉSUMÉ

The Dunkirk Water Syndicate (SED) manages an Industrial Water network supplying 16 industrial users, helping preserve drinking-water resources through the use of raw water from the Bourbourg Canal. In line with an industrial ecology and circular-economy approach, the project aims to reuse industrial wastewater, thereby reducing pressure on the water resource. The study identifies a reinjection potential of nearly 3 million m³/year into the Industrial Water network, requiring the integration of a quality module into the network’s hydraulic model.

This module, developed in PICCOLO by SUEZ Consulting, makes it possible to assess the impact of reinjection on the quality of the distributed water by simulating 32 physico-chemical parameters across different scenarios and periods (summer, winter, rainfall). Seven reinjection scenarios were analysed, involving various industrial sites and injection points. The simulations show that certain parameters (chlorides, sodium, potassium, COD, hydrocarbons, sulfates) are particularly sensitive to reinjection, with deviations that may be multiplied by a factor of 10 to 20 depending on the scenario and the location of the injection points.

The results highlight the importance of both the positioning of injection points and the reinjected volume in limiting negative impacts on water quality. Adjustments such as relocating injection points or modifying reinjection volumes help mitigate some undesirable effects. The quality-modelling tool is now fully mastered and enables the identification of viable reinjection solutions for industrial-process water, contributing to the decarbonisation of the Dunkirk territory