Ultrasonically improved galvanochemical technology for the remediation of industrial wastewater

•Ultrasonic pretreatment of the galvanocoagulant for wastewater treatment was proposed.•A mathematical model of this process was developed and confirmed experimentally.•The efficiency of preliminary ultrasonic treatment of the galvanocoagulant was proved.•The process duration was reduced by 20–25%.•A pilot semi industrial complex based on the method was developed and tested.

Two general methodologies adopted for the decontamination of industrial wastewater containing oil and metal ions are flocculation and coagulation. Both methods require the addition of chemicals and in the case of electrocoagulation the additional use of electrical power. Another methodology that was developed in Russia some years ago involves the production of Fe2O3 particles as coagulants by a galvanochemical reaction between iron and coke. Both of these materials are inexpensive and generally available in bulk. Ultrasonic processing of the particles generated in this reaction reduces the particle size of the Fe2O3 particles and provides surface cleaning making them more effective. Trials have proved their efficiency for the decontamination of wastewater made up in a laboratory and real wastewater from a carriage cleaning station on the St. Petersburg Metro. A mathematical model for the process has been developed.