Challenge

Odor complaints were overwhelming the staff at the Manatee County, FL, Wastewater Treatment and Collection Department located south of Tampa. It was also evident that continuing exposure of the sewer system infrastructure to hydrogen sulfide (H2S) gas was causing substantial corrosion problems.

Initially, the department addressed public odor complaints on a case-by-case basis. When an odor compliant was received, the complaint would be investigated, solutions evaluated and a bid created for the necessary equipment or service.

Eventually, this process proved too time-consuming and cumbersome for the County’s small staff, and when odor problems increased to an almost weekly occurrence, staff simply could not address odor concerns and keep pace with their other professional duties. “We couldn’t keep up,” says Jim Marble, Collections Systems Superintendent. “We needed to do more testing and better utilize our chemicals. We needed to make sure we were getting optimum performance from them.”

Solution

After working with Siemens Water Technologies, and determining the best solution in the Davis Process product line was the ODOPHOS® odor control process, the County decided to outsource the entire odor control operation. The only other option was to add considerable personnel, but that was not feasible since the odor problems tended to be seasonal in nature.

Siemens Water Technologies Odor Control offered a comprehensive solution, under a single contract, that included use of several of the company’s liquid- and vapor-phase odor control processes.

As appropriate, the Bioxide®, Bioxide-AQ® and ODOPHOS® liquid-phase processes are all in use on the Manatee County system to control targeted odor compounds.

In addition, Davis Process employs some of its vapor phase technologies, including wet scrubbers, biofilers, and carbon adsorption processes.

Davis Process is solely responsible for maintenance of all odor control processes. The County monitors results. All products and services are billed on a consumption or time basis, so there is no capital cost to the county.

Results

This unique approach to odor control works for Manatee County. By contracting with a single vendor offering multiple odor control options, the County gets the benefit of the a dozen different technologies—the most technically and economically advantage solution in each case. Furthermore, the County has a single entity to call to address any odor issue. Records indicate that “new problems” are typically resolved in less than two weeks, and problems at existing sites are resolved within 24 hours.

A dozen different Siemens' technologies are employed at various sites around the 22-million-gallon-a-day system. Consumer complaints have been effectively pre-empted.

Current population is approaching 300,000 and is expected to double in the next 25 years—due in part perhaps, by the absence of offensive odors from the wastewater collection system.