| Source Newsletter 2008 issue 1 |
|
 |
McLean Thermal Conserves Water, Saves Money
A Twin Cities-area manufacturer, McLean Thermal, recently implemented changes to save money by reducing the amount of water used. The company avoided one-time service availability charges (SAC) proposed by the Metropolitan Council to cover the water being used.
McLean Thermal of Champlin, Minnesota, designs and manufactures cooling systems for electronic enclosures. In 2006, the company was given the opportunity to avoid one-time charges of $23,500 if they reduced water usage by at least 700,000 gallons per year. The company also was facing increased chemical and labor costs associated with the frequent replacement of their cleaning chemicals. McLean determined that the costs of not reducing water and chemical usage were too great and contacted MnTAP for assistance.
Process description
To increase corrosion resistance and provide a foundation for painting, McLean operates two multi-staged iron phosphatizing pretreatment systems. As the parts pass through each of the stages, the solutions in the tanks are sprayed through nozzles onto the parts. Drainage from the parts is directed back into the tank from which it was sprayed.
Water use intern project
In 2007, a MnTAP intern at McLean researched ways to better use the rinse water to reduce water and sewer costs. The paint pretreatment rinse stages previously consumed 3.5 million gallons of city water per year in the form of continuous overflows. An additional 140,000 gallons of city water were used per year for the weekly cleaning and refilling of the rinse stages.
A recommendation was made for McLean to discontinue the addition of city water to each of the stage 4 rinse tanks. Instead, waste drainage from the deionized halo spray was directed to stage 4 rinse tanks to maintain an overflow of water. Not only did this reduce the amount of city water being used, but also provided stage 4 with purer water. McLean also began to reuse the relatively clean water from the stage 4 overflows for stage 2 rinse water. When compared with the fresh city water being used in stage 2, the stage 4 overflows were as clean or cleaner. As a result, the stage 4 overflows are now used as the stage 2 supply without degradation in product quality. This change has also resulted in less scaling buildup on the stage 2 tank and spray nozzles. Making this change required the installation of two flow meters, a flow regulator valve, and a new water pipe for each of the lines.
While monitoring the conductivity/TDS of the rinse tanks, it was determined that the frequency of rinse tank cleanings could be reduced. Instead of scheduling a rinse tank change each week, operators were instructed to perform weekly tests of the rinse stages and use the results of those tests to determine the proper time for dumping the rinse tanks. Operators have reduced the tank cleaning frequency from weekly to monthly, which is saving water and labor with no loss in rinse quality.
By implementing the recommendations from the MnTAP intern project, McLean Thermal anticipates an annual reduction of 1,380 gallons of chemicals, nearly 1.9 million gallons of water, and 2,600 therms of natural gas. Additionally, the company will avoid one-time SAC charges of nearly $25,000 and will continue to realize an annual cost savings of $20,000.
|
|
McLean Thermal Conserves Water, Saves Money
Technology Diffusion Helps Implementation
Steam Trap Testing Can Lead to Big Savings
Event: Making the Case for Efficient Energy Management
Jeff Becker Joins MnTAP, Provides Solutions
Grant Program Offers Assistance to Small Manufacturers
Seven Minnesota Companies to Host Interns
An Answer for Used Solvents Questions: Recycling
Materials Exchange featuring Chisago County Exchange
|
