Electrocoagulation Technology: Ace Plating Part II

Electrocoagulation is a process of applying a direct or alternating current and voltage of varying strength to electrodes in contact with water. In theory, this contact causes the suspended and/ or dissolved solids in that water to form into a floc or precipitate of sufficient size that it can be rapidly removed from the liquid by filtration. Electrocoagulation technology vendors promote the ability of this method to reduce water usage and the amount of metals discharged to the sewer. Electrocoagulation vendors claim the process removes 75-99% of metals and 90-99% of suspended solids while reducing BOD and COD by 50-75%. Sometimes the process is also marketed as having the ability to reduce the amount of inorganic salts in the water being treated. These claims were based primarily on laboratory data only. The vendors also stated that this process not only improved water quality over other technologies, but did so with lower costs. Reportedly, electrocoagulation would eliminate adding expensive chemicals to the wastewater and would subsequently generate less solid waste, thus saving on disposal costs. The Illinois Sustainable Technology Center (ISTC) investigated the electrocoagulation process to determine its effectiveness. If this technology could be proven to be as effective in actual process applications as reported in lab studies, it would be a valuable tool for cost-effective water recycling and reuse. ISTC worked with Ace Plating, an electroplater in the Chicago area that agreed to host a series of tests. ISTC engineers had previously worked with Ace to reduce their water usage, dragout, and metals discharged to the sewer (details about this project are available in ISTC publication TN13-066). The pollution prevention goal was to recycle the process rinse waters and eventually achieve zero process water discharge to the sewer. Equipment from two separate vendors was tested.