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Peter Wilkinson & Co Pty Ltd:
Breaking the open-loop solvent stream

The purchase of new solvent thinners and the disposal of waste thinners account for a large proportion of the operational costs incurred by businesses in the vehicle refinishing industry. For many body repair businesses, these costs are ongoing and seemingly unavoidable. The need to constantly purchase new thinners and dispose of waste thinners can have a significant impact on profitability, locking businesses into a one-way solvent stream rather than a closed system of solvent recycling. Through the use of an approved solvent recovery system, Peter Wilkinson and Co have managed to break free of the open-loop solvent stream, and in doing so, have improved resource efficiency, reduced waste management expenditure, and minimised potential sources of environmental pollution.


Peter Wilkinson and Co Pty Ltd is a Western Australian panel and paint repair workshop situated in Welshpool, an industrial area east of Perth's CBD. The company was established in 1959, and currently employs 23 full-time staff and repairs approximately 160 vehicles per month. In recognition of the growing financial and environmental problems associated with poor solvent management practices, the business made the decision to invest in a solvent recovery system in the mid-80s when the technology first entered the Western Australian market.

Problems with Previous Process

Whilst solvent management within the body repair industry has improved considerably in recent years, it has nevertheless been tainted by a long history of improper disposal practices. When the company first began its operations 44 years ago, waste contractors licensed to handle and transport waste solvent were practically non-existent, and suitable treatment and recycling facilities were not yet available in Western Australia.

Prior to investing in a solvent recovery unit, Peter Wilkinson and Co would purchase hundreds of litres of new thinners every month. Like many businesses in the vehicle refinishing industry, the volume of solvent thinners purchased would remain part of their annual waste inventory. Not only were waste disposal costs impacting on profitability, but they ensured that the business was locked into the waste shipping business every month.

Eco-efficiency & Cleaner Production Initiative

Solvent Recovery Systems

Waste solvent thinners are a potentially reusable resource that can be recycled in-house with very little effort. Through the process of distillation, solvent recovery systems convert paint-contaminated solvent into a clean and reusable solvent suitable for various applications within the body repair industry.

Waste thinners are emptied into a 25L capacity holding tank that is lined with a heat-resistant plastic bag. Heat is transferred to the waste solvent via a coiled heating element that surrounds the holding tank. When at operational temperature, the solvent boils and begins to evaporate. The vaporised solvent is then passed through a condenser where it is cooled by a fan, and converted back into the liquid phase. At the end of the distillation cycle, a semi-solid to hard crystalline residue - made up primarily of paint pigment - remains in the holding tank. In WA, this solidified waste is acceptable to dispose of to landfill in most instances.

The machine can process 25L of waste thinners in approximately 4 hours, and has a recovery rate of around 90%. The recycled solvent is of a quality suitable for use in the following processes and applications:

Because solvents are highly flammable substances, good solvent recovery systems should include a number of safety features such as over-temperature shutdown mechanisms, pressure relief valves and flameproof housings for the electrical components.

Advantages of the Process

Through onsite recycling of the waste thinners, Peter Wilkinson and Co are now able to effectively manage what was a seemingly intractable solvent waste problem. The recovery unit has provided the business with a practical and cost-effective mechanism for improving operational efficiency whilst simultaneously enhancing their overall environmental performance.


The 2001 Bellevue chemical fire in Western Australia is a clear example of the environmental risks associated with transporting, storing and treating large volumes of hazardous liquid wastes. Since incorporating solvent recycling technology into their operations, the business has substantially improved resource efficiency by recycling and reusing what was once considered to be a waste product. The environmental benefits of this simple resource conservation initiative arise from a significant reduction in raw materials, as well as practically eliminating all solvent disposal requirements. Having a smaller volume of solvents stored on the premises also reduces the likelihood that an on-site pollution event will occur.


The potential economic benefits to be gained from this technology were the primary motivating factor for purchasing a solvent recovery unit. The table below provides a general breakdown of the financial advantages the company has achieved since implementing this technology into the business.

Table 1: Calculating the Cost Savings of Solvent Recycling
Old Process (without recycling
VOLUME (L) Per month
COST (AUS$) Per month
New Solvent Purchases
200 (gunwash only)
$240.00 ($1.20 per litre)
Waste Solvent Disposal
$150.00 ($0.75 per litre)
Total Annual Cost (to buy and dispose of solvent)
New Process (with solvent recycling)
VOLUME (L) Per month
COST (AUS$) Per month
New Solvent Purchases (based on a 90% recovery rate)
~20 L (gunwash ONLY)
$ 24.00
Waste Solvent Disposal
Net price of solvent recovery system (using price of excisting machine)
Machine maintenance and operation
~$50.00 (Per month)
Estimated Annual Saving (with solvent recovery system)
No. years to pay back system *
3.9 years

* Payback periods will vary between businesses. Maintenance and operational costs of around $600/yr have been incorporated into the above calculations, however these costs are also variable depending on machine type and frequency of use.

Since Peter Wilkinson and Co have been using a solvent recovery system, they have saved approximately $2,880 per year ($240/month) in the cost of new gunwash thinner purchases. Added to these savings were associated reductions in collection and disposal costs for waste thinners. This has saved the business somewhere in the vicinity of $1800 per year ($150/month) in waste management related expenses.

These savings combined equate to an annual saving of $3,792. During the 15 years that Peter Wilkinson and Co have been utilizing this technology, the business estimates total savings in excess of $55,000.


The decision to invest in a solvent recovery unit was based on a long-term business strategy to increase economic efficiency whilst simultaneously improving the company's standard of environmental management.


The initial capital outlay for the solvent recovery unit was the only barrier experienced by the business in the implementation of this initiative. The solvent recovery unit currently being used by the business retailed for around $15,000 when it was purchased 7 years ago. Whilst the technology itself has changed little since then, there has been a significant reduction in the cost of these machines, with units similar to the one described above retailing for approximately $10,000.

Further developments

The business is currently investigating upgrading to its third solvent recovery unit.

Contact Information

Michael Wilkinson
1 Adrian Street
Welshpool WA 6106

Phone: (08) 9362 5622
Fax: (08) 9470 2241

S & S INDUSTRIES (Product Supplier)
Tony Siroen
25 Rothschild Place
Midvale WA 6056

Phone: (08) 9274 6566
Fax: (08) 9274 2259

This case study was prepared by the Motor Trades Association of Western Australia (MTA-WA) as part of an Eco-efficiency Agreement between the MTA-WA and the Australian Government Department of the Environment and Heritage, with funding assistance from the Natural Heritage Trust and Product Stewardship for Oil Program.