>Copper is a valuable commodity. No Chinese board house will be foolish enough to waste it. With modern processes, it's simply a case of neutralising the etchan

>Copper is a valuable commodity. No Chinese board house will be foolish enough to waste it. With modern processes, it's simply a case of neutralising the etchant and filtering out the precipitated copper. Except that motivation will only results in removing just as much copper as it's economical to extract. They'd still discharge the remaining copper once it reaches concentrations too low to bother extracting (but plenty high enough to cause damage to biological systems). This also ignores all the other stuff in the etching and rinse baths, which isn't exactly benign.