Acqueous Cleaning of RMA Flux

First, you must determine a few things:

1. What specific de-fluxing chemical are you going to use? Basic required determinations include the chemical�s pH, is it a VOC (if so, what is its VOC content), what concentration is the chemical used in (10% - 20% is common).

2. What happens to the wash water after it is used to clean the boards? Is it discharged or is it reused? If it is discharged, will the discharge be filtered (and to what micron level)? If it is captured and reused (your cleaning system may be equipped with a wash-water recycler), what will you do with the spent wash solution (drum and haul or filter and drain)?

3. You need to determine how much water in total (wash and rinse) will be sent to drain (if you are draining the solution). Batch machines (depending on the brand and model) will use from five to twenty gallons of water per load of boards.

I would recommend that the first agency you contact not be the EPA but rather your local municipal water district. These are the people responsible for determining what can and can not be put down the drain. In most cases, their restrictions are tougher than the EPA�s. The EPA may have no problem with your installation while your local water district may prohibit it.

In all likelihood, you should not experience a problem. We have more than a thousand customers who discharge filtered effluent directly into drains. For the few that can not, or choose not to (see below), they had two choices. They could connect an evaporator to their cleaning systems. All of the cleaner�s effluent is directed to the evaporator where the majority of the volume is boiled off. The remaining sludge is hauled away as waste. Another alternative to draining is close-looping the entire process. This is only possible (and financially desirable) if the application is 100% water soluble. In this case, all of the process water (wash and rinse) may be easily captured, filtered, re-deionized, and reused, thus eliminating the need for a drain.

Should you drain? As previously mentioned, you most likely can drain the solution after basic filtration. But there are reasons that you may choose not to. One motivating reason is the EPA practice of holding known dischargers of industrial waste financially responsible if lead is determined to be within a fifty-mile radius of permitted sites. If you are not connected to a drain, you can not be held responsible.

Please feel free to contact me with any additional questions.

Mike Konrad Aqueous Technologies 909.944.7771 ext 29 www.aqueoustech.com

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