Amstel rectifiers for water treatment such as waste water.
Excerpt from Wikipedia:
Electrocoagulation (EC) is a technique used for wash water treatment, wastewater treatment, industrial processed water, and medical treatment. Electricity-based electrocoagulation technology removes contaminants that are impossible to remove by filtration or chemical treatment systems, such as emulsified oil, total petroleum hydrocarbons, suspended solids, and heavy metals. A fully automated modular system has no filters to clean or replace and does not require the use of chemicals.