ROCK SPRINGS, WYOMING WWTP EXPANSION USING UNIQUE SOLIDS TREATMENT AND REDUCTION PROCESS

The City of Rock Springs, Wyoming, required an upgrade and expansion of their wastewater treatment plant (WWTP) because of growth and changing permit requirements. Plant improvements were designed and constructed, including a new solids reduction process called the Cannibal® system. The new system includes both physical removal and biological destruction of solids. Routine solids wasting are eliminated in the Cannibal system. Return activated sludge (RAS) is screened to remove trash and inert material. RAS is also pumped through hydrocyclones for removal of fine grit. A portion of the RAS is sent to a sidestream facultative reactor where the aerobic microbes are placed in an environment in which they cannot compete with the resident facultative microbes. The reverse becomes true when the facultative microbes are periodically returned to the aeration basins to become an eventual food source for the aerobic microbes. The net result of these biological processes is a near steady state condition and no regular solids wasting from the system. Operation and maintenance costs associated with solids handling are expected to be greatly reduced with the Cannibal system.