E. I. du Pont de Nemours & Co., Inc.
A Heinkel centrifuge unit is being installed to decrease the quantity of uracil herbicide carried into the filtrate waste stream. The stream is treated by the site's permitted bio-treatment system. In addition to the reclamation of the herbicides previously lost to the wastewater treatment system, a large percentage of the uracil herbicide unit's discharge of water will be recycled into the process, thereby eliminating a portion of fresh make-up water.
Although centrifugal filtration has often been used to improve marketable products, its sole purpose in this project was to improve waste stream characteristics so the site would be able to comply with new regulatory requirements on herbicides, effective December 1994.
This project has reduced one uracil herbicide in the waste stream by 8,900 lb/yr. It is expected to reduce the quantity of another uracil herbicide in the waste stream by 119,000 lb/yr. Total organic carbon (TOC) loadings to the site's wastewater treatment plant from uracil herbicide production will be reduced by 41% overall. Additionally, hydraulic loadings will be reduced 51%, and EPCRA emissions/wastes and uracil herbicides waste will also be reduced.
Details of Reductions
Additional Information :
Savings are estimated at $40,000 per year due to yield improvements and reduced treatment costs, alone. The substantial reductions of uracil herbicides in the wastewater provided additional time to evaluate other alternatives needed to meet even more stringent regulations, effective 1997. They also allowed the delay of $4MM in capital expenditures for "end of pipe" treatment. Recent evaluations indicate a possibility to avoid $3MM of that originally contemplated "end of pipe" treatment expense due to better source reduction and more economical treament alternatives.