Facultative Anaerobe Bioselector – Aerobic Digester

Application / Industry:  Municipal Wastewater Treatment
Customer Name:  Snowmass Water & Sanitation District, Snowmass, CO
Consulting Engineer:  SGM Engineering, Glenwood Springs, CO
Process Fluid:  Municipal Waste Activated Sludge
Process Treatment Method:  Aerobic Digesters No. 1, 2, 3


The Snowmass Wastewater Treatment Facility is located in the heart of a resort community. Their highest priority was to eliminate potential odor from hydrogen sulfide being emitted from the process. Management wanted to operate the system in an ON/OFF blower cycling mode to enhance the development of facultative anaerobe bacteria in the process fluid, which thrives in conditions of low dissolved oxygen and in processes where the oxygen supply is varied. These bacteria are the most stable available in nature for wastewater treatment and when in high populations, will not produce hydrogen sulfide gas.


Tideflex® Technologies Engineers designed a maintenance-free Coarse Bubble Mixing and Oxygen Supply System with the ability to operate on an ON/OFF basis, critical in development of the facultative anaerobes. While traditional diffuser systems operated with the blower off will result in full system clogging of the diffuser piping, Tideflex® Check Valve Diffusers prevent clogging, providing maintenance-free operation. The Snowmass operations staff was able to cycle the blower to produce varying ORP states without experiencing any mechanical problems in operation of the mixing system.


Snowmass utilized ORP (Oxygen Reduction Potential) probes to monitor the environmental state of the process fluid during the blower cycling.  Observation of this data allowed them to set the blower run times and down times in accordance with facultative anaerobe density. These digesters are operated in series with the first stage digester operating at 60% blower run time and the second stage digester operating at 30% blower run time.  At start-up, during operation and after stabilization of the facultative colony, the waste sludge process fluid discharges no hydrogen sulfide gas or odors.

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