On Hawaii’s Big Island, a forward-thinking wastewater treatment project has successfully introduced a compact aeration and clarification solution that ensures environmental protection while extending the life of aging infrastructure.
Many smaller treatment plants process less than 500,000 gallons per day and often operate with just one aeration pond, one clarifier, and no redundancy. As liners deteriorate and grit accumulates, these facilities face mounting risks of environmental contamination and costly violations.
Expanding sites is rarely an option—making innovative, space-saving solutions essential.
At a 300,000 GPD extended aeration activated sludge facility built in 1995, WSI International partnered with Landia to design a temporary yet robust system that enabled the utility to take its only aeration basin offline for cleaning and relining—without disrupting operations.
To achieve this, WSI converted the site’s existing secondary clarifier into an aeration basin by integrating a compact Dissolved Air Flotation (DAF) system. This created the necessary redundancy for both aeration and clarification, all within the plant’s limited footprint.
A critical part of the solution was Landia’s AirJet diffuser. Designed as a venturi system, the AirJet entrains atmospheric air into a recirculating flow, ensuring both aeration and mixing without the need for intrusive installations.
Unlike traditional blowers or aeration grids, the AirJet’s nozzles are mounted externally, simplifying installation and maintenance while avoiding interference with existing clarifier equipment.
“Some aeration options required large nozzles inside the clarifier, which would have been nearly impossible to install,” explained Ben Garcia, vice-president of Engineering at WSI.
“The Landia AirJet allowed us to introduce aeration nozzles through the clarifier wall, while the chopper pump remained outside. This provided exactly the right amount of oxygen and mixing needed for the biological process—keeping solids in suspension and preventing sediment build-up.”
The successful installation not only enabled the lagoon to be safely taken offline for relining but also gave the facility long-term operational flexibility it had never had before.
“The Landia AirJet worked exactly as designed,” Garcia added. “It runs smoothly, is easy to maintain, and gave us the confidence to complete this challenging project. Both we and our customers are very happy with the outcome.”
Big Island wastewater plant welcomes small-footprint aeration solution
