The toughest challenge at the SKF manufacturing site, in Cajamar, Brazil, is the removal of the elevated concentration of oil and grease in wastewater, which comes from the use of solvents during the machining process. This stable mix of oil and water is very difficult to separate.
The previous treatment system at the site relied on conventional ‘physical-chemical’ methods, which require large amounts of chemicals to remove the contaminants. This was not achieving the targets set by legislation, which stipulate a biological oxygen demand (BOD) reduction of at least 80%. BOD is a water quality parameter that indicates the concentration of biodegradable components present in the water.
Cleanit-EC, an electrocoagulation based treatment process- was chosen as part of an integrated solution, comprising of pre-treatment and final polishing to meet SKF’s precise requirements.
Cleanit-EC is a water treatment method that uses submerged metal electrodes with an electrical current running through them. It offers superior treatment of oil in water emulsion because the electrodes release metal ions that form metal hydroxides, destabilizing the emulsion. The impurities then coagulate and either settle on the bottom or float to top of the water, making them easy to separate.
Cleanit-EC electrodes offer greater efficiency for the electrocoagulation process because of their high porosity, and therefore higher active surface area for treatment.
The new system using Cleanit-EC technology is a compact and automated solution that not only meets the BOD reduction required by the legislation, but also enables the treated water to be re-used in some factory processes.
The advantages of the new system using Cleanit technology include:
- An automated process
- A compact system
- Use of much lower quantities of chemical products
- Lower interaction of the operator with the chemical products, making the process safer
- Reduction of operational costs
- Meets BOD reduction demands required by legislation
- Treated water can be used in other processes