Since 2007 Terneuzen's municipal household waste water flowing via a special pipeline to Dow, where it is reused and then used again. As results, Dow reduces its dependency on regional fresh water, while saving energy and reducing greenhouse gas and chemicals usage. The region of Zeeuws‐Vlaanderen in the Netherlands, where Dow Terneuzen site is located, is structurally short in fresh water. Therefore Dow, Evides (the region’s water provider), and the Water Board have joined their efforts to sustainably control the regional water balance. The main steps given to solve the problem were:
- Provide the necessary infrastructure at the Dow site and in the region;
- Build new water production facilities at the City WWTP (Membrane Bioreactor) and at Evides (facility known as "DECO");
- Reuse of Dow's internal fresh wastewater effluent as cooling tower supply water.
Dow's Terneuzen site in the Netherlands accepts more than 2.6 million gallons of municipal household waste water every day. The local water producer removes residual contaminants and Dow then uses more than 70% of this water to generate steam.
After use, it is reused in cooling towers at the site until it finally evaporates into the atmosphere. Three million tons of water per year that was previously discharged into the North Sea after one use is now used an additional two times.
This effort results in 90 percent less energy use at this facility compared to desalinating this amount of sea water and a reduced need for water treatment chemicals.
The reduced energy use is the equivalent of lowering carbon dioxide emissions by 60,000 tons per year.
Furthermore, this project has some specific features:
- Production and distribution costs are affordable by an innovative use of existing regional piping infrastructure and relatively simple adaptation of the previously used equipment;
- Concept and technology has high leveragability to similar situations both in the Benelux and abroad (collaboration between regional companies, water boards and industries).
Within the frame of Dow's 2015 Sustainability Goals, this successful project has gained great attention within Dow and has substantial potential to be applied at other locations as well. Besides, it has won the Responsible Care 2007 prize given by the Dutch Chemical Industry Council (VNCI).
Some of the challenges faced were:
- Regional infrastructure had to be adapted, requiring investment for channel crossing and 6 km pipeline;
- Long infrastructure pipelines suffer from biofouling and need treatment to protect downstream unit operations.
This project brought the following benefits to Dow and the community where it operates:
- Reduced intake of fresh surface water by 2.5 million m3 annually;
- 65% reduction in energy use compared to the previous operation;
- Lower chemical dosing to prevent membranes from fouling;
- At the City WWTP an MBR (membrane bioreactor) was installed (2010) achieving superior effluent quality for reuse in combination with increased treatment capacity;
- The city WWTP effluent discharge to the river was lowered by an equivalent amount.