Case Study – Cold Water Nitrification for Rigby, ID

THE CHALLENGE:

Nitrifying Throughout the Winter

Eight Degrees Celsius – that is the typical minimum wastewater temperature that the City of Rigby Wastewater Treatment Facility experiences each winter. A new permit for the Rigby WWTP meant they needed to keep their nitrifying bacteria through the coldest part of each winter. Their most recent permit included a very stringent ammonia limit during the winter – monthly average of 0.65 mg/L – which must be achieved by October 1, 2024.

WHY THE MOB PROCESS WAS CHOSEN:

• Low installation costs
• Minimal impact to existing operations
• No new process volume
• Easy to install, and straightforward to operate – “It’s like plug and play, and it works great!” Scott Humphreys, the Wastewater Superintendent

WHAT WAS ACHIEVED:

• Increased Treatment Capacity by nearly 3x – per engineer’s capacity analysis
• Achieved Cold Weather Nitrification down to 8°C
• Utilized Existing Facility for a Rapid Retrofit
• Proven Less Susceptible to Process Upsets