Wastewater treatment facilities serving food-service districts are increasingly challenged by quaternary ammonium compounds (QACs), disinfectants that can inhibit nitrification even at 2–5 mg/L. For plants with heavy restaurant flow, inhibition from QAC loading is a common cause of ammonia spikes, biological upsets, and recurring nitrogen exceedances.
This was the case at the Derby St. Shops onsite wastewater treatment facility in Hingham, Massachusetts, a retail center with more than 60 food-service businesses. The facility struggled with chronic nitrogen permit exceedances driven by severe QAC inhibition and needed a sustainable, chemical-free solution.
Download the full case study: https://www.moleaer.com/case-study-derby-st
Woodard & Curran, the site’s operations and compliance team, traced the problem to
These conditions made it difficult for the facility to maintain stable nitrification, leading to ongoing ammonia and total nitrogen exceedances.
To restore biological performance without major upgrades or chemicals, the facility integrated Moleaer’s nanobubble pretreatment solution at the influent to the first Rotating Biological Contactor (RBC).
This low-footprint wastewater pretreatment step strengthened nitrifying bacteria under high toxic loading, enabling the existing RBC process to function as intended.
Nanobubble pretreatment also operates chemical-free, requires minimal maintenance, and fits within constrained plant footprints, making it well-suited for decentralized wastewater facilities.
Following installation of the nanobubble pretreatment system, the facility achieved:
To see the full performance data, download the complete case study.
The detailed case study includes:
See the full data, year-over-year graphs, and operational details from Derby St. Shops: https://www.moleaer.com/case-study-derby-st