EnviroMix delivers O&M savings and process benefits through multi-phased BioMix upgrade

Pollution Control Works (PCW) in Russellville, Arkansas 

BioMix nozzle headers installed on the tank floor of an anoxic selector in Phase I. 

City Corporation, a nonprofit that manages the water and wastewater systems for the city of Russellville, operates the Russellville Pollution Control Works (PCW) facility which provides wastewater treatment for 30,000 residents, local industry, and the city of Dover. Constructed in 1964, the PCW utilizes an activated sludge process. Recent upgrades were conducted in two phases, both of which included EnviroMix’s BioMix Compressed Gas Mixing System.

Phase I

Completed in 2014, the goal of Phase I was to upgrade the facility to achieve compliance with nitrate effluent limits via conversion to a Modified Ludzack Ettinger (MLE) process, including the addition of anoxic selectors upstream of the aerobic zone and a nitrate-rich internal mixed liquor return from the aerobic zone to the anoxic selectors.  

The BioMix system was chosen to mix eight anoxic selectors created within the existing footprint of two operating process trains as well as four anoxic selectors in a new process train. Minimizing maintenance and providing significant energy savings, BioMix utilizes one compressor system versus the alternative of 18 mechanical mixers. Additionally, BioMix does not impart measurable oxygen, creating optimal anoxic conditions.  

Duty and standby rotary screw compressors serve the BioMix system. 

Phase II

Completed in 2022, the goal of Phase II was to upgrade the facility to achieve biological phosphorus removal via conversion of the MLE process to an Anaerobic-Anoxic-Oxic (A2O) process. This upgrade included the addition of anaerobic selectors upstream of the anoxic selectors which receive primary effluent and return activated sludge (RAS) to facilitate the selection of phosphorus accumulating organisms (PAOs), with subsequent release of phosphorus under anaerobic conditions and the excess accumulation in the aerobic zone.  

BioMix was chosen to mix the anaerobic selectors due to the ease of installation and because the technology does not impart measurable oxygen, creating optimal anaerobic conditions. Integrated with the controls for Phase I, Phase II simply required the addition of nozzle headers, a local valve module, and a master control panel. Further reducing capital costs, the 40-psi low-pressure rotary screw compressors (duty/standby) were sized during Phase I with adequate capacity to serve the future Phase II, eliminating the need for additional compressors. 

The Pollution Control Works (PCW) in Russellville, Arkansas 

Results

In Phase I, the BioMix system saved the Russellville PCW an estimated 75% in energy consumption versus traditional mechanical mixers. In Phase II, the system saved the PCW more than 60% in energy consumption versus traditional mechanical mixers. EnviroMix is proud to partner with repeat customers like City Corporation, providing communities like Russellville with long-term operation and maintenance savings and optimal process control.