SDOX PROVIDES EMERGENCY SUPPLEMENTAL AERATION
MUNICIPAL WASTEWATER TREATMENT PLANT
Application: Oxidation Ditch Aeration
Engineer: BlueInGreen LLC
Goals: Rapid Deployment | Supplemental Aeration
A wastewater treatment plant in Northwest Arkansas utilizes an oxidation ditch process incorporating separate anaerobic and anoxic basins for biological nutrient removal. The aerobic ditch is equipped with four constant speed brush aerators to add dissolved oxygen to the process. The majority of the plant influent is received from local food processing facilities, which often contain high organic and nutrient loading. During these times, the dissolved oxygen (DO) levels in the oxidation ditch consistently drop, prohibiting effective treatment. After experiencing a recent high influent loading, the facility’s four brush aerators were unable to provide enough aeration to maintain positive dissolved oxygen levels, and the plant was at risk of losing the ability to meet permit requirements.
With nitrification at a standstill and biological oxygen demand on a steady incline, plant operations and management contacted BlueInGreen for help. Within 8 hours BlueInGreen was onsite with a skid-mounted SDOX® unit. Within an hour of installation, the SDOX was supplying a supersaturated stream of DO into the oxidation ditch, supplementing the oxygen provided by the brush aerators. Delivering an industry-leading 98% transfer rate, the SDOX was able to supplement aeration almost instantaneously.
OPERATING THE SDOX FOR 1 HOUR INCREASED DO TO 3-MG/L, A LEVEL PREVIOUSLY NOT SEEN BY PLANT OPERATORS.
At a flow rate of 350,000-gpd, the brush aerators maintained a DO of 1.4-mg/L in the oxidation ditch. Operating the SDOX for 1 hour increased DO to 3-mg/L, a level previously not seen by plant operators. On average, each 30-hp brush aerator increased the DO approximately 1-mg/L per pass (from 1-mg/L to 2- mg/L), while the SDOX produced a DO increase of approximately 1.6-mg/L per pass (from 1.5-mg/L to 3- mg/L). Utilizing VFDs and innovative designs for optimum efficiency, the SDOX solution was able to provide this increase at only 18-hp – nearly three times less energy.
“WE WANT ONE OF THESE.” – PLANT OPERATOR
The SDOX system allowed the municipality to maintain permit limits with increased loading without having to correspondingly increase the plant footprint. BlueInGreen’s state-of-the-art technology immediately increased the DO, maintained higher levels of treatment and saved the facility from costly sanctions. At the request of the plant operators, the SDOX will remain onsite to further investigate O&M cost savings by pausing the brush aerators and monitoring DO concentrations and corresponding levels of treatment. Their ultimate goal is to identify design criteria for full-scale implementation in the near future.