Processing Magazine

Industrial goods maker tackles water costs with ultrafiltration system

Meets twin goals of saving money and reducing environmental impact

March 1, 2013

Prab Ultrafiltration PR0313When a maker of industrial fastening systems located in the Southwest United States looked to improve overall operations, one of the first projects it tackled was dealing with the vast amount of water associated with its part washing and annealing processes.

The plant maintenance manager and a maintenance technician developed the business case for recycling that water and reducing water use. Once implemented, an ultrafiltration system cut water consumption by hundreds of thousands of gallons, slashed waste disposal costs and brought a new revenue stream into the plant for the reclaimed oil.

The industry-leading manufacturer produces durable fasteners for operation in extreme conditions. Markets for these high-quality engineered fastening systems are driven by rigorous standards within the transportation, aerospace, automotive and oil & gas industries.

As demand for its product increased, the manufacturer looked for improvements across its entire operations and processes. In particular, steps that would both improve efficiency and limit environmental impact were sought. The most significant process point at which the two criteria both came into play was the annealing process.

Challenge involves toughness

As is well known, annealing is a thermal process whereby metals and other type materials are subjected to heating and slow cooling so as to increase toughness while reducing brittleness. It’s essential that the parts be properly cooled, subsequent to the application of high temperatures, and this is typically done using city water.

In addition to being annealed, the parts are placed in large washing machines to clean off any machining oils. This also requires a great deal of water. The manufacturer ran five of these washing machines, with each wash cycle pulling fresh water from city lines. On average, the parts washers consumed 1,000 gallons of water during a five-hour shift. When at peak loads, water consumption could easily be more than double this amount.

To begin recycling this water, the high concentration of entrained oil from the parts as they came from the machining centers would first have to be dealt with.

Heretofore, the manufacturer dealt with this water using a centrifuge system that sucked the oily water into drums. The drums were then stored on-site and periodically hauled away. Storing the drums took up valuable space, and the manufacturer had to pay a contractor to haul away the hazardous materials. Given ever-increasing costs for city utilities and machining oils, combined with a corporate initiative promoting environmental stewardship, the maintenance and management team was able to make a solid case for exploring viable filtering and recycling options.

An ultrafiltration solution

During its investigation, the team reached out to PRAB engineers, tapping into the company’s 60 years of fluid-filtration experience. Working as an integral partner on the project, a pilot ultrafiltration system was installed in the facility for a trial evaluation. The system proved very successful in a very short period. Capital funding was approved for the purchase of an ultrafiltration system, which paid for itself within just eight months of installation.

Ultrafiltration systems separate emulsified oils and suspended solids from wastewater and coolant, reducing oily water volumes by as much as 98% without the use of chemical additives. System effluent water can then be safely discharged to the sewer or reused in the manufacturing process.

The system implemented by the fasteners maker includes:

• Magnetic Separator – removes ferrous particulate to 20 microns.

• Tramp Oil Separator – removes free-floating and mechanically
dispersed oils.

• Ultrafiltration – removes emulsified oils and particulate to a level of 0.05 micron.

The cost of operating this system is just two cents per gallon — far below the combined expenses of incoming city water, sewer charges and subsequent haul-away cost.

The ultrafiltration system allowed the fastener-system manufacturer to achieve the following project goals:

• Eight-month simple payback on equipment purchase and installation.

• Reduced fresh water consumption by a projected 130,000 gallons annually, at an estimated savings of more than $274,000.

• Saved nearly $96,000 in hauling and disposal costs for the oily water. This total was expected to increase to more than $261,000 in the next year due to increasing environmental disposal costs and the rising demand for fasteners.

• Added a revenue stream for the reclaimed oil, at 30 cents per gallon.

For more information on PRAB Fluid Filtration equipment, visit, email or call (800) 493-3462.