Patent for highly efficient nitrate removal process donated to Water Environment Research Foundation
The formal presentation of the patent to WERF was held at the Alexandria Sanitation Authority. The patent, issued to BASF Corp. by the U.S. Patent and Trademark Office under U.S. patent number 6,426,004 in 2002, details how to conduct nitrification and denitrification of wastewater in a single treatment tank, which is commonly referred to as Timeswitch technology and is different from the traditional multiple-compartment approach.
The Timeswitch method was discovered during BASF’s efforts to reduce the amount of nitrate compounds in the discharge from its Freeport, Texas, manufacturing site. Engineers at the site had been looking for ways to modify the wastewater treatment plant on the site. Wastewater experts from BASF’s Freeport site, as well as from other BASF locations in the U.S. and Germay, jointly developed the Timeswitch technology using computer simulations and pilot plant testing. BASF did not implement the process, but has retained rights to practice the technology under the donation agreement with WERF.
Typically nitrogen removal is accomplished in aerobic and anoxic tanks, vessels, or compartments of a wastewater treatment system. Since aerobic and anoxic treatments are incompatible, two tanks were thought to be the minimum number of vessels needed to operate both aerobic and anoxic processes. With the Timeswitch method, nitrates can be removed from water at municipal and industrial wastewater plants in a way that eliminates the need to invest capital in constructing an additional tank. With only a few new controls and mixers, both aerobic and anoxic treatment can be accomplished in one tank.
“This is exciting new technology that helps address a critical environmental issue,” said Cenan Ozmeral, BASF’s Group Vice President for Petrochemicals in North America. “The Timeswitch patent could be a very effective answer for municipalities and businesses that need or want to reduce nitrates in their water streams.”
According to WERF, nitrogen control is one of North America’s most significant environmental water quality issues. Nitrogen discharges are the primary cause of water quality and environmental problems in the Gulf of Mexico, Chesapeake Bay, the Outer Banks of North Carolina, and other regions. Potential users of the Timeswitch treatment technology include municipal wastewater treatment plants, industrial wastewater treatment plants at manufacturers - such as food processing, steel manufacturing, and chemical and pharmaceutical manufacturing--and concentrated animal feeding operations. For many facilities, use of the Timeswitch invention would allow nitrogen removal with minimal changes compared to the usual add-on approach, resulting in capital and operating cost savings.