Cracking down on solvent abuse

Around 50% of manufacturing companies in the UK are still using trichloroethylene and similar solvents for degreasing: Elga has helped achieve high performance aqueous washing at Renishaw

Should companies continue to use such solvent degreasing systems after 31st October this year, they could face prosecution under the Solvent Emissions Regulations 2004.

The allowed alternative, using high purity water from Elga Process Water in aqueous based washing machines, can produce results as good as solvent cleaning systems, as Gloucestershire based measuring equipment manufacturer, Renishaw, discovered.

Renishaw uses Mecwash Midi 400 washing machines to remove cutting oils from its precision machined components.

"We noticed that some of our parts, particularly satin chrome plated components, suffered staining even when they were rinsed in demineralised water," explains Development Engineer Neil Wood: "We now use Elga Process Water Aquaclean service exchange cylinders to improve the quality of our demineralised water by an order of magnitude, and that eliminates the staining".

Renishaw uses two Elga Process Water Aquaclean cylinders in series, the first containing activated carbon and the second containing a mixed bed of cation and anion exchange resins.

Using Elga service exchange cylinders also has environmental benefits.

Renishaw now recirculates water from the rinse tank, which used to be discharged to waste at a conductivity of about 100uS/cm.

Passing the water from the rinse through an Elga Process Water Aquaclean exchange cylinder upgrades its quality to about 5uS/cm and allows recirculation, thus reducing mains water consumption and eliminating the need to discharge into the local sewerage system.

Service exchange users like Renishaw have a duty of care to ensure that their wastes are disposed of safely.

In the case of resin disposal, this means having a fully documented audit trail to trace the resin route from the process finishing areas to its ultimate fate.

Some service exchange suppliers simply dispose of spent resin to landfill, but regeneration is a much more sustainable solution.

Elga Process Water operates the the largest UK regeneration centre at Stoke-on-Trent, where it handles ion exchange resins from many different industries.

The Elga Process Water Environmental Management System ensures that every batch of resin that comes into the centre is identified and fully traceable back to its previous regeneration, and that includes a record of compliance of regeneration wastes with the discharge consent.

Disposing of exhausted resin into a landfill simply doesn't provide the same level of traceability.

Compliance with the Solvent Emissions legislation means a move to aqueous based washing techniques.

These need not be any more expensive than solvent degreasing but water quality is of paramount importance in ensuring a high quality finish.

Service exchange is both convenient and cost effective, so long as the service provider can provide full traceability for the resin life.

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