The copper industry is a major contributor to the global economy. How to remove it from wastewater provides benefits to more than just the companies mining copper and fabricating products from it. Copper is an essential component in the motors, wiring, radiators, connectors, brakes, and bearings used in the automotive sector, for example. The removal of heavy metals such as copper from industrial wastewater is very important due to its harmful effects on human health. There are many techniques to treat different types of industrial wastewater that are contaminated with heavy metals such as copper.
In this article, we can provide clear answers about the use of electrocoagulation (EC) advanced oxidation (AOP). We intended to endorse the use of this technology in several wastewater treatment plants located over the world. Not only in copper removal but also in the removal of hard molecules on industries like aeronautics, automotive, chemicals, detergents, textile or shopping malls.
VentilAQUA’s electrocoagulation technology considered in this case is a continuous flow system, composed by multi-stage cells, with multi-electrode, containing special electrodes of suitable material for the function of oxidation and coagulation, with modular configuration and special internal geometry for optimum efficiency, totally build in PE / PP.
This system also includes a specific electrical box to supply electrical stabilized power to the electrodes, with the automatic anti-passivation process. Also, the electrochemical capacity adjustment to adequate the oxidation process according to the objectives.
That means the electrocoagulation process is set in terms of power, and electrical current intensity, optimizing the electrolysis reaction. These settings will be provided by manipulating the electric current rectification unit, in addition to the flow settings and amount and distribution of the electrodes.
This treatment is designed for a treatment cycle to obtain:
- Minimization of operating costs of the unit – the use of low energy technology; use of a set of automation to reduce the need for hand labor operation, control, and maintenance.
- The efficiency of the treatment – the use of high-quality materials and equipment, developed by leading suppliers to the world market.
The Copper Wastewater
The wastewaters to be treated are coming from a yarn production process that generates a current with a high concentration of copper. These wastewaters are characterized mainly by the presence of a copper content between 1.000 –5.000 mg/l and a very low pH around 1. It was tested also in a very high concentration of copper, 23.600 mg/l.
The lab tests were conducted under these premises and result in the design of a treatment solution based on a chemical electrocoagulation process, on a maximum daily capacity of approx. 12 m3/day.
The electrocoagulation process removes the metals without applying any pH change. There is an electrodeposition process of the metals running on electrodes. It is clear that electrocoagulation has good results on removing metals, and they can be optimized by operation time and energy consumption.
After the electrocoagulation process, a pH neutralization is performed to be on the values of the permit environment regulation. Also, this will make inherent hydroxide metals precipitation, increasing the overall efficiency.
Findings and conclusions
The viability and efficiency of this technology to remove copper from this wastewater are proved. This means less operating costs and better efficiency results, as it shows above:
- > 99.9% removal of copper
- > 99.79% removal of Zinc
- No coagulants needed
- Low power cost, best results of 0.140 Watts per gram of copper removed
- Improved sludge dehydration performance
- The system demonstrated a very good efficiency, above 99%;
- Clarified treated water
The future of wastewater treatment
Downstream the electro-coagulation, we can add the traditional methods of sludge separation by settling or by flotation. The combination of the Dissolved Ozone Flotation and Electrocoagulation system will result in an extremely strong application to remove the most difficult molecules. We have several examples around the world either combining Dissolved Ozone Flotation and Electrocoagulation or separately. We can even combine these systems with biological treatment plants once Ozone will not affect the activity downstream. The compatibility of these technologies, including Electro-coagulation, with biological treatment, is perfect. We can use it for revampings, or retrofit. We can increase the efficiency of existing plants by introducing these technologies into existing processes. They can be modular, and they can be fitted into existing plants. Read more