A porous gas diffusion electrode for polymer electrolyte membrane fuel cells. Specifically, the wastewater includes one or more organic contaminant materials and is pre-treated prior to filtering by the following steps The pH of the wastewater is adjusted to a pH in the range of about 2 to 6, and a combination of iron salts and peroxide are added to the wastewater and allowed to react for a period of at least about three minutes. The substrate block may be coated with a bio-active surface coating material such as hydroxyapatite or a calcium phosphate to promote bone ingrowth and enhanced bone fusion.