Before he retires in 1999, John Maliszewski, CEO of Reliable Plating Works, Milwaukee, Wisconsin, plans to have his plant at zero discharge. He already has one fully automated line at zero discharge and another well on its way. The third line will be completed within two years.
Planning for zero discharge began two years ago and included the addition of a nickel-chromium plating line and facility. The addition includes 26,000 sq ft of warehouse, manufacturing and office space built by Briohn Building Corp., a company partially owned by Mr. Maliszewski. The new nickel-chromium line uses a mix of reverse osmosis and ion exchange technology, counterflow rinses and evaporation to achieve zero discharge.
Not only did Reliable work on planning the building and plating line, it worked with Atotech USA, Inc., Somerset, New Jersey, to develop a trivalent chromium plating chemistry that would produce a blue-bright finish that rivaled hexavalent chromium.
As part of its plan, Reliable plated customers' parts with both trivalent and hexavalent chromium and mixed the finished parts together in the shipments. When Reliable asked its customers to distinguish between hexavalent and trivalent chromium plated parts, they could not tell the difference.
After six months, Reliable went to its customers and explained that the trivalent chromium produced the same appearance as the hexavalent without the hazardous wastes associated with hexavalent chromium plating. Reliable wanted to plate all trivalent chromium as part of the zero-discharge plan.
Customers in the automotive, appliance, furniture and paper dispenser businesses liked the zero-discharge plan and gave Reliable the "go-ahead" to plate trivalent instead of hexavalent chromium.
The return-type, programmed automated-hoist plating line from Jessup Engineering has the capability to run a number of processes. At present it is programmed to run five different cycles. Reliable has the ability to make minor adjustments to the programs. If a new program or troubleshooting is required, the system is hooked up via computer modem to Jessup, who can make changes and help Reliable with any problems 24-hrs a day, seven days a week.
"We may not be a big company," stated Jaime Maliszewski, president and son of John, "but many of our customers are. If we are down, our customers are down."
Parts begin at the cleaning tanks where they undergo:
Before use, city water is cycled through either reverse osmosis or ion exchange. Reliable found that the only way it could achieve zero discharge was to "cleanup" the city water. The process removes lead, copper, magnesium, calcium, sulfur and other contaminants. These contaminants could end up in the final sludge, making it undesirable for reclamation. Or they could interfere with the plating process. Reliable knows that the cleaner the trivalent chromium solution, the better the appearance of the finished parts. This is especially true for trivalent chromium plating.
Water from the rinse tank after the electrocleaner is run through a sand filter, carbon filter and ion exchange. Water from the ion exchange column is then pumped back into the final rinse of the cleaning process at 10 gpm. All rinses in the cleaning cycle are counterflowed.
When one of the two alternating ion exchange columns is backwashed (every third day), solution flows to a 6,500-gal heated surge tank. It requires approximately 800 gal of water to backwash one ion exchange column. From the surge tank, backwash is then pumped through an evaporator to reduce the volume by 1,805 gpd. Material from the evaporator is pumped into a 6,500 gal by-product tank. When the by-product tank is full, it will be shipped to Inmetco, Ellwood City, Pennsylvania, for reclamation. Mr. Maliszewski estimates that it will take three and a half years before the first shipment is made.
Backwash from the sand filter is also pumped into the by-product tank and shipped for reclamation. Oil removal from the cleaning solutions is being examined and if successful will be shipped to Heritage Environmental, Indianapolis, Indiana. Strippers are evaporated into a heavy paste that is sent to Inmetco.
Periodically, the filtration systems are blown down. All the Slim Line filters from Anode Products have a built-in adapter, originally designed by Reliable Plating, through which compressed air is fed. This dries the filter contents, which are then bagged and shipped to Inmetco for reclamation.
Following cleaning, parts enter one of eight nickel tanks, each containing 10 oz/gal of nickel and running at 50 asf, 145F. DI water is used for makeup and process water on the plating line. There is no running water after the acid dip rinse. There are triple counterflowing rinse tanks with spray rinses following the nickel plating process. The available nickel plating processes include bright nickel at 0.5 mil, satin nickel at 0.5 mil, duplex nickel at 0.5 or 1.2 mil thickness.
All of the nickel tanks have Techmatic, Inc. evaporators, which evaporate solution at 40 gph. "We have evaporated nearly 270,000 gal from our nickel tanks in the first three months, and 7,000 gal from our trivalent tanks so far this year," Mr. Maliszewski estimated. All the nickel solutions are run continuously through a carbon filtration system at 5,000 gph.
Following nickel plating, parts enter the trivalent chromium tanks. The trivalent chromium contains 2.7 to 3 oz/gal of trivalent chromium and 7.1 oz/gal of boric acid. It is run at 50 asf and 110F. This is followed by a 130F triple counterflowing rinse. The trivalent chromium tank also has an evaporator that evaporates solution at 40 gph.
After trivalent chromium plating, welded parts are passivated in a 140F solution containing 0.5 oz/gal hexavalent chromium. That is followed by a 130F triple counterflow rinse. The hexavalent chromium tank has a Cosmos Minerals Corp. purifier on it along with evaporation. The purifier keeps the trivalent chromium out and the chlorides down.
Bath concentrations are manually maintained. Temperature is controlled automatically and amp-hr meters are used for brightener control. Hull cell tests are run daily, and once a month Atotech runs tests on the plating solutions.
There are no sewers (except sanitary) in the new facility. The cement used in the floor was made from silica, which is ten times finer than regular concrete. With the epoxy coating on it, it is able to withstand 50 pct sulfuric acid for an unlimited time.
"The city (Milwaukee) told us that if we get our older lines operating like the newer one, they would no longer have to come into the plant. We would have to supply six months of documentation first," noted Mr. Maliszewski. "My sons are taking over the company, and I won't leave until it is zero discharge. I don't want the liability."blog comments powered by Disqus