MWF disposal – the dual approach

A combination of novel formulatory techniques and advanced waste separation processes are currently under development in a two year project to address the environmental pollution issues facing the users of watermix metalworking fluids (MWFs). Tony Lesowiec of the project co-ordinator, Pera, reports.

During the last twenty five years, there has been a significant increase, globally, in the use of watermix metalworking fluids (MWF’s), sometimes wrongly referred to as just coolants or suds, to replace neat or mineral oil based fluids. And although today’s fluid formulations have been greatly advanced by the development of novel additive packages, the purpose of these products remains unchanged: to provide lubricity; to cool; to prevent surface corrosion; to remove metal fines (swarf) from the cutting process; and to prolong the life of the cutting tool.

Today’s fluid formulations have been greatly advanced by the development of novel additive packages.

Watermix fluids have, during this period of time, become ever more sophisticated and adaptable to a wider and wider range of machining operations and requirements. The improvements in machining efficiencies, the advantages with respect to productivity and the benefits to the local working environment are all well documented but these advances are not without limitation.

Cocktail of components

The watermix MWF, during its lifetime in use, is particularly prone to degradation by a number of outside sources which are difficult to control. This inevitably results in a requirement to dispose of a fluid which can contain anywhere between 90-97% water which has been combined with a complex mixture of surfactants, corrosion inhibitors, biocides and other mixed solubility components. The disposal of this cocktail of components is extremely difficult, especially as a result of the number of hydrophilies present.

Currently many of the smaller users of these fluids simply store the fluid and call in specialist waste treatment companies to remove the material. The larger users, such as automotive manufacturers and heavy engineering-based organisations, have set up chemical treatment plants to handle the waste on site, preparing the water for disposal to drain. Somewhere in the middle lie those users that create relatively large quantities of waste MWF but find it hard to justify the cost of a full treatment plant simply to reduce the on-site problem.

In order to provide some indication of the scale of the waste problem in Western Europe, the UK, which is in the top five users of watermix MWFs in the region, produces around 20,000 tonnes of product per annum. Whilst there are other losses to be considered during the use of the fluid, if the most commonly used fluid preparation level is applied to this figure, i.e. five parts MWF to 95 parts water, on a simplified level this equates to 400,000 tonnes of waste fluid per annum.

In recent years, with increasing legislative restrictions to disposal with respect to both landfill and water source return, the applied costs of MWF wastage has continued to rise.

Legislative spotlight

Alongside the cost implications certain components of the fluids have also come under the legislative spotlight. Committees such as the Oslo and Paris Commission (OSPARCOM) have been created to control the chemical components that might, from a waste disposal viewpoint, have an effect ultimately on marine life. It has become increasingly important therefore for suppliers of these fluids to be conscious not only of the in-use performance of the watermix MWFs, but also how the componentry used may ultimately affect the potential disposal characteristics of the products. Similarly, from the user standpoint it has been necessary to consider more exacting and cost effective disposal methods to reduce the commercial demands produced by the current and potential legislation.

As a result of these industrial concerns, a two year project was set up under the framework of the European Commission Craft Programme with a consortium of eight partners providing complimentary technical expertise and end user experience: additive supplier Polartech Ltd; fluid formulators Fimitol GmbH, Zorelor SA, Brugarolas SA and JP Industrie; and technology providers Enviro-Bac Ltd, Lanstar Ltd and Koch Membrane Systems. The aim of the project is to develop MWFs for low or reduced cost disposal based upon the current and potential legislative disposal requirements of the European Union.

This is being approached by two main routes, utilising the expertise of the fluid formulators and the disposal technology providers:

Development of novel watermix MWFs which are free from components likely to be unacceptable from either a disposal or health and safety standpoint. Formulatory approaches will also be highlighted that positively assist in the disposal process;

Evaluation of current and potential methods of watermix MWF disposal and a consideration of the option to either integrate those methods or develop a totally new cost effective route.

Innovative work has been carried out with respect to formulatory concepts of the fluids at both laboratory and pilot scale and a number of novel formulations have been devised. These have subsequently been distributed to suitable end user sites to determine their suitability for use prior to being considered from a disposal viewpoint.

In tandem, extensive evaluation of disposal technologies has been completed at the Pera research facility and this has lead to the development and design of a prototype hybrid system which could be adaptable across a wide range of user requirements.

Specific benefits

As the project nears completion, the combination of new metalworking products and novel disposal treatments will be utilised at workshop sites to confirm the specific economic and environmental benefits of the programme which are expected to arise from:

Development of MWFs capable of meeting current and future legislative regulations throughout Europe with respect to disposal and health and safety requirements;

Potential reduction in factory economies with respect to waste removal as a result of more efficient and capable on-site disposal technology;

Greater flexibility in managing waste costs as a result of maximising product life and minimising and controlling exact disposal outputs.

It is expected that all consortium members will be able to gain significantly from the results of the programme, and chairman of the Exploitation Committee, Robert Stubbs of Polartech Ltd, is particularly pleased with the progress.

“It has been very refreshing to see the frank and open exchange of views between the members of the consortium in an industry that has been traditionally very secretive about its own in-house technology. This has resulted in a very high level of cross fertilisation of ideas between the fluid formulators and the disposal experts providing some interesting and novel conclusions to the project’s goals.”

A full list of consortium members, including contact details, is available in the reference section of edie’s library.

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