Consortium tackles water mix metal working fluid disposal
Consortium tackles water mix metal working fluid disposal
Keyword Metal working fluids
The dual approach of novel formulatory techniques and advanced waste separation processes is currently under development in a two year project to address the environmental, ecological and technical issues of the disposal of water mix metal working fluids (MWFs). Tony Lesowiec of the project co-ordinator, Pera, reports.
Manufacturers of MWFs are often rightly focussed on formulating products to meet the ever increasing demands of machining processes imposed by the end user engineering sector. The cost of additives and base oils also plays a part in the final fluid make up. But how many formulators consider the disposal of the fluid as a primary consideration?
With tightening environmental legislation and rising disposal costs, the waste treatment of spent fluids is becoming increasingly important. One only has to take a look at the current situation in Germany where end users are under pressure to clean up their act by recycling their wastes on site or face expensive disposal costs. The principle of polluter pays is the name of the game. The following strategy advocated by European legislative bodies is becoming increasingly evident.
First priority. Prevention/reduction of waste at source.
Second priority. Promotion of recycling recovered materials at end user sites.
Next. Promotion of recycling waste materials as a secondary fuel energy source. Last resort disposal to environment.
In order to provide some scale of the waste disposal problem in Western Europe, the UK, which is in the top five users of water mix MWFs in the region, produces around 20,000 tonnes of product per annum. 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.
Disposal
Traditional waste treatment methodologies such as ultrafiltration and chemical separation are limited in their capabilities as stand alone technologies, and almost completely ineffective for the fully synthetic fluids where there is no emulsified oil to separate. Evaporation technology however, which is commonly used by our European partners, is largely capable of treating these fluids. Biotechnology is a promising alternative treatment option for spent fluids, unlike the others it is based on destruction of the pollutants rather than separation and concentration. Its biggest drawback is its slow treatment rate. The key to optimising this technology is to identify an effective method to neutralise the toxicity in the fluids.
The recovered water from these primary treatment processes is usually suitable for sewer disposal and this is policed by the Environmental Agency. One of the main cost influencing factors for sewer discharge (based on the Mogden formula) is the chemical oxygen demand (COD). It is therefore important to target COD reduction in any treatment systems. This means providing effective technology for dealing with the dissolved organic components such as corrosion inhibitors, coupling agents,biocides and dyes. Other parameters that need targeting are the oils and grease levels in the water phase and of course the total volume of waste. One of the primary aims of the Pera project is to further polish this recovered water to a suitable quality to enable reuse on site e.g. for preparing new fluid mixtures,for washings or cooling etc. thereby preventing/reducing sewer discharge. This has the double benefit of reduced disposal costs and saving purchasing fresh mains water. If ultimately the water is sewer discharged it would cost less to do so because of the reduction to COD.
One must not loose sight of the disposal of by-products from any treatment system. Both an oil phase and solid phase are also likely to be produced. The solid phase may consist of dirt,grit, sludge, particulates or flocculants and these are usually disposed of in landfill. This is becoming increasingly unattractive due to rising costs and tightening legislation. In some cases the recovered solid phase is incinerated although this is more expensive than landfill. The recovered oil phase can contain a high percentage of water and other contaminants. This phase is normally collected by waste treatment companies for low level processing involving dehydration and filtration to produce a burner fuel product or is used without processing as a support fuel in kilns in the cement manufacturing industry.
Component legislative spotlight
Alongside the cost implications of disposal, 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 view-point, 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 water-mix MWFs, but also how the component used may ultimately affect the 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 complementary technical expertise and end user experience. These European based partners consist of additive supplier Polartech Ltd; fluid formulators Fimitol GmbH, Zorelor SA, Brugarolas SA and JP Industrie; and waste treatment technology providers EnviroBac Ltd, Lanstar Ltd and Koch Membrane Systems. The aim of the project is to:
develop MWFs for low or reduced cost disposal based on current and potential legislative disposal requirements of the European Union; and
develop a cost effective waste treatment system for these products.
This is being approached by two main routes, utilising the expertise of the fluid formulators and the disposal technology providers:
- 1.
Development of novel water mix MWFs which are free from components likely to be unacceptable from either a disposal or health and safety standpoint. The selection of components that have been identified as contributing to lower COD and toxicity of the fluid and thus have enhanced treatment capabilities on fluid disposal.
- 2.
Evaluation of innovative and current disposal methods for water mix MWFs with the view to optimising and integrating those best performing technologies to provide a 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 evaluated at end user sites to determine their suitability for use prior to being considered from disposal viewpoint.
In tandem, extensive evaluation of the 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 fluid products and novel disposal treatments will be utilised at workshop sites to confirm the economic and environmental benefits of the study 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;
reduction in end user disposal costs by improving the quality of waste and recycling the recovered water phase on site and so reducing the volume of waste;
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, Mr 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 projects goals.
For further details please contact Tony Lesowiec, Pera, Melton Mowbray, Leics. Tel: +44 (0) 1664 501501;Fax: +44 (0) 1664 501556; E-mail: MAILTO:tony.lesowiec@pera.com
Some of the information used in this article first appeared in "MWF disposal the dual approach", Industrial Environmental Management, August 1998.
