Breckenridge, Colo., is one of the premier tourist destinations in the United States. However, after the installation of a septic/camper dumping station at the wastewater plant, tourism was threatened by odor complaints.
The septage operation was installed at the Breckenridge Sanitation District?s Wastewater Treatment Facility in the fall of 1994. Breckenridge?s odor problem became most apparent the next summer when use of the dump site was extremely high. That fall, the town decided that a solution must be found and $125,000 budget was allotted for the project.
Breckenridge eventually selected a NuTech Environmental QCID Odor Control System which was supplied and installed for $35,000. The simplicity of the system allowed the plant staff to do the entire installation themselves.
The treatment plant?s septage receiving tank has a volume of just under 4,000 cubic feet and is next to a pre-treatment room. Before the project began, the tank was not ventilated or under negative pressure and thus allowed odors to escape. This combined with the odors from the influent channel bar screens and the pretreatment room caused a serious problem for the surrounding area. The building?s ventilation system changed the air four times an hour, continuously discharging diluted odors into the outside air.
While the septage dumping tank and the pre treatment room were adjacent to each other, one of the two influent channel bar screens was approximately 100 feet away and was not easily accessible for ducting. The pre-treatment room was 15 feet high, 48 feet long and 20 feet wide. The ventilation rate for the room where the grit and screenings were removed and stored was calculated at 1,600 CFM. An additional 400 CFM of ventilation was determined for the aerated septage receiving tank.
To accommodate this, NuTech recommended a 2,000 CFM QCID (Quick Contact In-Duct) odor control system. The system uses a forced contact chamber to mix odorous air with the company?s vapor phase reactant chemicals. To ensure that contact with the air stream is complete, a services of fixed media contact packings are situated in the chamber.
Breckenridge?s QCID system is powered by a 2 HP three-phase motor that can easily pull the 400 CFM from the septage receiving tank through the use of a manually adjusted butterfly valve. The chemical feed system for the QCID system incorporates a 10 gallon chemical mix tank for the dilution of chemical, a mechanical float valve to maintain solution and a vacuum operated proportioner to control chemical usage.
A sealless, magnetically coupled, fractional horsepower gear pump supplies the chemical solution to the nozzles. The system has the ability to operate multiple nozzles. In addition to the two nozzles in the QCID contact chamber, there is a single nozzle positioned at the front of the bar screens.
The QCID system consists of a discharge stack, roof curb adapter, 4-inch butterfly valve, 4-inch PVC piping and a chemical feed system. The system has been in operation for three years.
?The system has worked very well for both the septage odor and the raw sewage odor. There is minimal upkeep and labor associated with the operation (of the equipment) ... the chemical consumption rate has been low beyond expectations,? said Plant Manager Greg Brown.