With a proper coolant management system, water based coolants (synthetic or semi-synthetic) can be recycled to provide a decent service life. However, they will build up hardness with time and eventually become contaminated to the point that they no longer performs as needed. The spent coolants have to be disposed and this can be expensive. To minimize the cost, membrane ultra-filtration (UF) can be an effective solution.
UF can separate most of the water from the spent coolant to meet local discharge limits. This is a cost-effective method compared to other alternatives on a per-gallon basis. Haul-away is a common way of disposal. This is not only a costly choice but also allows a third party (the waste disposer) to expose the company (the waste generator) to potential long-term liability. Evaporators, being an energy-intensive method, are also expensive and often require permitting as a point source for air emissions. Chemical absorbent is non-regenerative. It is expensive and is labor intensive. FSI's WRS Wastewater Recycling Systems are specially designed to recycle metal working fluids, aqueous cleaners, and coolants.