Waste & environment - Waste water comes full circle06 June 2005

Ford has commenced tests of a pilot plant that can completely recycle waste water from the company's vehicle paint shops in Saarlouis, Germany. The Saarlouis site produces the new Focus and Focus C-MAX models.

A key stage of the paint process is phosphating, which protects against corrosion and improves the adhesion of subsequent paint coats. The waste water contains particles, grease and dissolved salts. The new process starts with the decomposition of biologically-degradable substances using bacteria, followed by filtration through nanometre-sized pores in membranes. The process is completed by reverse osmosis to generate pure water, which may then be recycled back to the paint shop.

Germany is a world leader in the use of membrane technology to filter waste water and the Deutsche Gesellschaft für Membrantechnik, in Munster, is described by its Geschäftsführung, Professor Winfried Schmidt, as a, "union of 80 companies" engaged in the field.

At a meeting in London to promote the environmental technologies of North Rhine Westfalia, Schmidt gave Plant Engineer the inside track on what is currently the world's largest membrane filtration plant. Based at Kaarst, near Dusseldorf, the plant was set up to improve the quality of the Nordkanal, a small artificial canal that connects Germany and The Netherlands. The treatment plant had to produce 'bathing water-quality' effluent. Specifications included: total coliforms < 500/100ml, faecal coliforms 100/100ml and salmonella 0/1000ml. It was decided that these criteria could best be met using ZeeWeed hollow fibre membranes made by Zenon, a Canadian company. ZeeWeed is made from polyacrylonitrile.

The plant was opened in early 2004 and has a peak capacity of 45,000m3/d. The plant does cost more than a conventional waste water treatment plant, but occupies half the land area. The membrane area is 80,000m2. Biological oxygen on demand (BOD) is reduced from 300 to less than 3mg/litre, chemical oxygen on demand (COD) from 600 to less than 20, total suspended solids is reduced from 350 to not detectable, and turbidity is less than 0.05.

Ford does not claim its technology is cheaper than existing processes, but Hugo Clysters, head of the company's European environmental quality office, justifies it thus: "Ford is committed to reducing the environmental impact of vehicles over their entire lifecycle. This means not only developing environmentally advanced vehicles, but also producing them in environmentally responsible ways. The innovative combination of several state-of-the art water treatment technologies makes the Saarlouis project unique. By means of this pilot plant, we aim to analyse the transfer of processes developed in a laboratory to large industrial-scale application. We are optimistic that this new treatment process has the potential to significantly reduce the footprint of automotive manufacturing."

In 2000, Ford Motor Company chairman and CEO Bill Ford announced a global water management initiative, focusing on further water conservation, reuse and water quality management. As part of this commitment, Ford has conducted several global pilot projects at plants to identify precisely all processes using water so that it can look at the best ways to reduce water use and generation of waste. The company accepts that sustainable development is one of the key issues facing industry in the 21st century. Manufacturing-related environmental matters, such as water conservation and treatment are subject to the ISO 14001 standard.

SOE

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