Controlled Hydrodynamic Cavitation for Reduction of Toxic Metals in Metallurgical Residual Effluents

Wastewater must be treated before being disposed in receiving bodies, in order not to cause negative impacts on the environment. The goal of this research was to determine the effectiveness of treating metallurgical industry wastewater with controlled hydrodynamic cavitation (HC) in terms of removing metals, total suspended solids, and sulphates. A sample of wastewater was collected from a polymetallic (lead, coper and zinc) mineral processing facility in Peru and treated using a cavitation system. The system controlled flow, time, and pressure for 1.5 hours at 5 and 9 bars of pressure and temperatures between 22 and 64.4°C. The results showed that hydrodynamic cavitation effectively reduced the levels of metals, total suspended solids, and sulphates, with the best results achieved between 60 and 90 minutes of treatment at 9 bars of pressure. With an average removal of 73.6 %. for metals, 52.1 % for total solids in suspension, 3.9 % for sulphates and pH reduction of 14.7 %. This indicates that hydrodynamic cavitation is one of the sustainable technologies for wastewater treatment and low cost of operation and maintenance.