Community Research and Development Information Service - CORDIS

Recycling water from industrial waste

Papermaking can cause water pollution. In an effort to eliminate this problem, an Innovation project has validated a new technology - water recycling by waste-water evaporation - which could prove extremely valuable to industry and the environment alike.

Background

Enormous...
Papermaking can cause water pollution. In an effort to eliminate this problem, an Innovation project has validated a new technology - water recycling by waste-water evaporation - which could prove extremely valuable to industry and the environment alike.

Background

Enormous amounts of fresh water are contaminated by the paper industry during manufacturing processes. The water is taken from local rivers or lakes and returned as effluent which, in turn, causes water pollution. Separating the water from the industrial waste by evaporation is the best solution to this problem because the water can then be recycled and re-used repeatedly, without the risk of unwanted solids building up in the system.

However, there are many technical and economic difficulties associated with using conventional evaporation equipment, including high investment and energy consumption, corrosion and scaling. A new evaporator has been invented in Finland which is able to overcome these drawbacks. The underlying idea was to use thin plastic sheets as the heat-transfer surface instead of metal plates, an innovation which makes it possible to build large, corrosion-resistant heat-exchangers at low cost.

Description, impact and results

To bring this European invention to full commercialisation, its reliability in continuous operation needed to be validated through a full-scale trial on-site in a paper manufacturing company. This was the main aim of the European Commission's Innovation programme project "Bleach plant effluent treatment via a low-cost evaporator". Other objectives included optimising the design, and developing a system for inhibiting the build-up of oxalate scale on the equipment.

The project finished after only three years, one year earlier than planned, and three patents have now been filed as a result of the work. In addition, the project has already encouraged sales of the new equipment, with more than ten different applications currently in use in seven countries world-wide.

Water recycling by waste-water evaporation could have far-reaching environmental and economic impacts. Similar applications for treating effluent are found in nearly every major industry. World-wide, the potential is estimated to be worth at least 15 thousand million over the next decade. Turning seawater or even polluted water into drinking water could be another huge market for the novel technology. Other spin-offs are currently being discussed, and a Finnish development project has already begun to further increase the capacity of the new evaporator.

Working partnerships

The project team was coordinated by Hadwaco Ltd Oy, the Finnish developer and manufacturer of the new evaporator. Polymer technology knowledge was provided by the Helsinki University of Technology, Finland. Anti-scaling agents were supplied by the chemical company, Nalco Europe from the Netherlands. The plastic used was manufactured by the Dow Chemical company in Spain and was processed by the plastic-film manufacturing company, Ab Rani Plast Oy in Finland. The trial was carried at the Swedish pulp and paper company, Stora Paperboard AB (presently Stora Enso). Pressure drop and other operating conditions concerning the heat exchanger were calculated by the Finnish consultancy, Chemitech Consulting Oy.


Source: European Commission, DG XIII/D.4 - Information and dissemination of scientific and technical knowledge
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