Challenge

Located in New Haven, Indiana, the new facility was built in 1992 to manufacture brass air compressor fittings for automobiles and appliances.  Before approximately 165 gpm of wastewater could be discharged, it needed to be treated for the removal of chromium, copper, lead and zinc. Prior to providing an advanced wastewater pre-treatment system, the following tasks were completed:

• Prepared a detailed description of the plating process
• Analyzed the survey data and segregate the manufacturing waste streams to ensure their compatibility with the treatment process
• Evaluated the economics and expected performance of standard Siemens treatment technologies
• Defined the treatment system’s space, plumbing, electrical and other service requirements to ensure that the equipment would be completely integrated with the plant processes

In a future 1997 upgrade, the plant wanted to recycle approximately 50 gpm of brass torch quench water as well as increase the capacity of the existing microfiltration system by 50%.

Solution

A state-of-the-art microfiltration system was provided for the rinses from the brazing, plating and polishing processes.  The chrome-bearing and non-chrome-bearing waters are segregated into their respective equalization tanks.  The chrome-bearing waters are treated with sodium bisulfite to reduce the hexavalent to trivalent chrome prior to being blended with the non-chrome-bearing waters.  The waste is pH adjusted to induce metal hydroxide precipitation prior to being pumped through the microfilter for solid/liquid separation.  The metal-free wastewater is discharged to the POTW and the sludge is pressed and dried.

Recycling of the brazing torch water is accomplished by a two bed ion exchange system.  50% of the brazing torch water is pumped through a cation and then an anion exchange system.  The purified water is blended with the balance of the untreated torch water to produce city quality water which is recycled back to the brazing stations.

Results

• All regulated heavy metals leaving the microfiltration system are <0.1 mg/L.
• The actual operating cost for the microfiltration system is $3.56/1,000 gallon of wastewater treated, saving Parker Hannifin almost $9.00/1,000 gallon over a conventional wastewater treatment system.
• By incorporating a mezzanine and an additional bank of membrane modules, a 54% expansion in their treatment capacity was obtained.
• $50,000 savings was realized by modifying the design of the wastewater treatment room to include the secondary containment.