- Email: [email protected]
Reusing rinsewater
required for an outer layer in a duplex system; electrochemitally it is more like the nobler inner layer (usually semibright nickel). Berl Stein, Plating Research, N.J. Thanks, Berl, your reply is very enlightening. Gordy Seppanen, Honeywell Inc., Minn.
AIR PERMITS FOR CHROME PLATING All plating shops that have any type of chrome plating tank are now required to obtain a Title V air permit. The EPA has eliminated the lo-ton/yr criteria for chrome tanks and lumped them all into the “major source” category, regardless of what your potential to emit (PTE) actually is. The latest NESHAP for source categories 63.345-63.347 states [63.340 Applicability and Designation of Sources]: “(a) The affected source to which the provisions of this subpart apply is each chromium electroplating or chromium anodizing tank at facilities performing hard chromium electroplating, decorative chromium electroplating, or chromium anodizing. . . . (e) The owner or operator of an affected source subject to the requirements of this subpart is required to obtain a Title V permit from the permitting authority in which the affected source is located.” This also doesn’t differentiate between trivalent and hexavalent chrome plating tanks as far as needing the permit. Paul Peterson, Albert Lea Electroplating, Minn. Do you think that, by any stretch of the imagination, chromating solutions could be included in this permit? Tom Pullizzi, Team*Faraday, N.J. They are not including chromates or any chrome bearing solutions that are not electrified. The EPA has a bulletin board where anyone can get up-to-date information on air permitting and other topics. The number is 919-541-1447. Paul Peterson, Albert Lea Electroplating, Minn.
Established
REUSING RINSEWATER We stopped using noncontact cooling water in our rinses because of the oil contamination from bad heat exchangers. The city water that comes into our plant in the winter is about 45°F and only warms up 2-3°F by the time it makes it to the rinse tanks. We are looking at alternatives for tempering the water, including cleaning up and reusing the water as we move towards zero discharge. Does anyone have an opinion on reusing rinsewater? What technology is best for cleaning up the water? What are some potential pitfalls? Are there other alternatives for tempering our rinsewater? We have the typical processes of a medium- to high-tech circuit shop, but our most critical process is wire-bondable gold. Charlie Hayes, ACSIST Associates, Minn.
Charlie, reusing the rinsewater is a very sensible approach that I’ve always advocated. You can go about it in several ways. First of all, for it to be cost-effective, you want to cut down on the overall rinsewater demand by using countercurrent rinses, reusing the rinsewater from the acid dips in the rinses following alkaline cleaners, which incidentally helps to accelerate the diffusion of the cleaners, etc. With warm plating tanks (nickel, chromium, etc.) you can do direct recuperation, which is much more cost effective than any kind of treatment. For the acid-alkaline rinsewater, reverse osmosis should be sufficient before recycling. The advantage here is that there is no need to introduce additional chemicals into the system such as with ion exchange. The greatest pitfall, of course, is the accumulation of impurities in the loop. Everything has to be closely monitored after it has been meticulously designed, but it is certainly doable and well worth the effort. Berl Stein, Plating Research, N.J. Ted Mooney is an independent consulting engineer based in Kinnelon, N.J. MC
1967
Innovative Manufacturer of Flexible Lining Systems to recycle or prolong the life of your tanks. “High Temp” PVC Drop-In Liners
Easy Installation Highest Quality Savings Writeor CalIfor Information: P.O. f3OX 3908 . Shawnee, OK 748023908 ??
??
In OK: (405) 2754600
??
FAX (405) 275-4625
l-800-633-4603 Ext.400 Circle
METAL FINISHING . APRIL 1995
073 on fwder
lnfomation
card
63
AIR PERMITS FOR CHROME PLATING All plating shops that have any type of chrome plating tank are now required to obtain a Title V air permit. The EPA has eliminated the lo-ton/yr criteria for chrome tanks and lumped them all into the “major source” category, regardless of what your potential to emit (PTE) actually is. The latest NESHAP for source categories 63.345-63.347 states [63.340 Applicability and Designation of Sources]: “(a) The affected source to which the provisions of this subpart apply is each chromium electroplating or chromium anodizing tank at facilities performing hard chromium electroplating, decorative chromium electroplating, or chromium anodizing. . . . (e) The owner or operator of an affected source subject to the requirements of this subpart is required to obtain a Title V permit from the permitting authority in which the affected source is located.” This also doesn’t differentiate between trivalent and hexavalent chrome plating tanks as far as needing the permit. Paul Peterson, Albert Lea Electroplating, Minn. Do you think that, by any stretch of the imagination, chromating solutions could be included in this permit? Tom Pullizzi, Team*Faraday, N.J. They are not including chromates or any chrome bearing solutions that are not electrified. The EPA has a bulletin board where anyone can get up-to-date information on air permitting and other topics. The number is 919-541-1447. Paul Peterson, Albert Lea Electroplating, Minn.
Established
REUSING RINSEWATER We stopped using noncontact cooling water in our rinses because of the oil contamination from bad heat exchangers. The city water that comes into our plant in the winter is about 45°F and only warms up 2-3°F by the time it makes it to the rinse tanks. We are looking at alternatives for tempering the water, including cleaning up and reusing the water as we move towards zero discharge. Does anyone have an opinion on reusing rinsewater? What technology is best for cleaning up the water? What are some potential pitfalls? Are there other alternatives for tempering our rinsewater? We have the typical processes of a medium- to high-tech circuit shop, but our most critical process is wire-bondable gold. Charlie Hayes, ACSIST Associates, Minn.
Charlie, reusing the rinsewater is a very sensible approach that I’ve always advocated. You can go about it in several ways. First of all, for it to be cost-effective, you want to cut down on the overall rinsewater demand by using countercurrent rinses, reusing the rinsewater from the acid dips in the rinses following alkaline cleaners, which incidentally helps to accelerate the diffusion of the cleaners, etc. With warm plating tanks (nickel, chromium, etc.) you can do direct recuperation, which is much more cost effective than any kind of treatment. For the acid-alkaline rinsewater, reverse osmosis should be sufficient before recycling. The advantage here is that there is no need to introduce additional chemicals into the system such as with ion exchange. The greatest pitfall, of course, is the accumulation of impurities in the loop. Everything has to be closely monitored after it has been meticulously designed, but it is certainly doable and well worth the effort. Berl Stein, Plating Research, N.J. Ted Mooney is an independent consulting engineer based in Kinnelon, N.J. MC
1967
Innovative Manufacturer of Flexible Lining Systems to recycle or prolong the life of your tanks. “High Temp” PVC Drop-In Liners
Easy Installation Highest Quality Savings Writeor CalIfor Information: P.O. f3OX 3908 . Shawnee, OK 748023908 ??
??
In OK: (405) 2754600
??
FAX (405) 275-4625
l-800-633-4603 Ext.400 Circle
METAL FINISHING . APRIL 1995
073 on fwder
lnfomation
card
63