The City of Alta wastewater treatment plant utilized a trickling filter treatment system that was constructed in 1950 and then upgraded several times. Recent changes to the water quality standards required lower ammonia nitrogen and bacteria discharge limits that the treatment efficiency of the existing system could not meet.

Following an in-depth evaluation, the City was provided with the recommendation to abandon the trickling filter plant and construct a new Aero-Mod, Inc. SEQUOX® activated sludge system. This activated sludge treatment system is an innovative system that incorporates aeration tanks, clarifier tanks, and digester tanks into one unitized design. This system results in a more energy efficient operation and a smaller footprint compared to other activated sludge designs, thereby lowering capital costs.

After three months of service, discharge sample data from the Aero-Mod system was compared to the effluent quality of the old plant. The new treatment system showed significant improvements over the existing system, yielding an average reduction of CBOD5 by 55%, TSS by 75%, and NH3-N by 91% over the treatment efficiency of the old plant.


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