Toxic wastes, electrolysis

In the results the emissions of mercury appear to have a very substantial contribution for the human toxicity impact score. These emissions are caused by the coproduction of chlorine and sodium hydroxide by electrolysis using a mercury cell. However, this technique is phased out. Therefore, the process descriptions in the Ecoinvent database do not represent up to date technology. In the Ecoinvent database the process for PVC production, in which chlorine is used as one of the compounds, is an aggregated processes based on, seemingly outdated, data from PlasticsEurope. These outdated data also influence the impacts related to waste treatment by incineration because sodium hydroxide is necessary for the waste incineration process. 

Unfortunately, some aquifers are being contaminated by seepage of toxic substances from agricultural products (and in some cases leakage of improperly stored industrial wastes). The removal of such contaminants by packed bed electrolysis applied to the exit pipe from the aquifer would allow continued use of these waters. 

The plating baths used in the various applications of electrolysis often contain toxic materials or produce toxic by-products. After bath solutions have been used for a period of time, they must be changed and the toxic contents disposed of in a safe manner. Remarkably, electrolysis offers one of the safest and most thorough means of cleaning up toxic metal-containing wastes. When the bath solution is subjected to electrolysis, the toxic metal ions are reduced to free metal at the cathode. The metal can then be recycled or disposed of safely. 

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