Optimizing dissolved oxygen and retention times for maximum impact
The focal point of the optAER® system is the fine-bubble aeration distributed through our diffusers placed at or near the lagoon bottom.
optAER fine-bubble aeration diffusers provides excellent operational flexibility they can operate in an airflow range between 5 to 25 SCFM. The airflow can be adjusted to accommodate variable load conditions and provide cost effective future upgrades to increase capacity.
The fine bubbles produced by the diffusers both rise more slowly (compared to traditional “coarse bubbles”) and result in high total surface area per volume of air introduced into the system, increasing the overall oxygen transfer efficiency of the system. The bubbles also mix the water, ensuring aerobic conditions throughout the water body.
The diffusers can be combined with self-tensioning floating laterals providing cost effective installation. For high diffuser density applications, Nexom's patented Float-Sink retrievable header system that enables easy access to the headers and diffusers for routine maintenance. Installation and maintenance for both floating and float-sink lateral aeration systems can occur without de-watering the lagoon or taking cells out of service.
Aerated ponds in the optAER process produce no nuisance odors when the system is operated within the specified design parameters. If anoxic ponds are included within the treatment process, odors can be controlled by the use of floating covers.
cBOD is reduced to carbon dioxide, water, and inert ash by natural bacteria, which receive their oxygen supply from air provided through the optAER aeration diffusers.
Suspended Solids Removal
Through the rise of bubbles and subsequent mixing, convection cells are created between diffusers. Not only does the water rise with bubbles, the solids settle out through the downward motion of the water between diffusers where the circulation loop is completed. The mixing rate is reduced in the secondary cells to minimize turbulence and facilitate additional suspended solids removal. Covered cells are used to control algae to meet stringent suspended solid limits. In addition, infini-D™ Zero-Downtime Cloth Disk Filters can be used for additional suspended solids removal.
The optAER system provides a combination of aerobic and anaerobic sludge digestion within the sludge layer at the bottom of the pond. Oxygen provided by the optAER diffuser allows for aerobic digestion at the sludge-water interface. Further, long-term sludge digestion occurs under anaerobic conditions within the settled sludge layer. The environmental impact and cost of sludge removal and disposal can be minimized with the optAER system due to minimal organic bottom sludge accumulation. The low sludge production also retains the pond retention time required for long-term cBOD removal.
Tools in the optAER® Toolbox
In addition to fine-bubble aeration, the optAER system takes advantage of the following technologies to optimize lagoon performance: