Characteristic hazardous waste spent caustic streams from five processes were repiped for reuse in a listed hazardous waste pretreatment unit that required fresh caustic addition. Specifically, the reused spent caustic waste stream backed out purchased caustic and as a result reduced hazardous waste generation and discharge to the company's overall wastewater treatment system. The final waste discharged from the pretreatment unit, while still hazardous due to listing, is no longer characteristic hazardous due to high pH. Since the spent caustic waste streams were removed from the company's overall wastewater system, this also significantly reduced the amount of acid required for neutralization. After completion of the project, a significant reduction in the generation of hazardous waste and a reduction in the amount of purchased caustic and purchased acid was realized.
This was a project which required the cooperation of several different operating departments in order to reduce the generation of hazardous waste. The caustic reuse system was designed to prevent any potential cross-contamination of products between the different operating department.
This project reduced the generation of hazardous waste spent caustic by approximately 21,000,000 lbs. per year. Also, eliminating the requirement for this waste to be treated and ultimately discharged as wastewater at Texas Eastman's permitted discharge to the Sabine River.
Details of Reductions
Additional Information :
Savings due to reduced purchased caustic and acid $ 468,900 per year. Payback period for project was 1.25 years.