Improving BNR Process Stability and Aeration Energy Optimization Through Low-Maintenance Low-Range NH4 and Process Monitoring（pH, ORP, DO, MLSS）
Tuesday, September 29, 2026 3:00 PM to 4:30 PM · 1 hr. 30 min. (US/Central)
New Orleans Convention Center
Technology Spotlight
Hall H Booth 7249
Information
Improving BNR Process Stability and Aeration Energy Optimization Through Low-Maintenance Low-Range NH4 and Process Monitoring
In recent years, Biological Nutrient Removal (BNR) processes at municipal wastewater treatment plants have increasingly adopted ABAC (Ammonia-Based Aeration Control) strategies to improve nitrogen removal performance while reducing aeration energy consumption. In the U.S. wastewater industry, growing emphasis on decarbonization, net-zero initiatives, energy-positive utilities, and workforce shortages has accelerated the need for operational strategies that enable more stable treatment performance with less energy and fewer operator interventions. Because aeration systems typically account for 40–60% of total plant energy consumption, optimization through low DO operation combined with ABAC has become a major focus for utilities seeking sustainable and cost-effective operations.
However, successful implementation of these advanced control strategies requires reliable and stable low-range NH4-N and DO monitoring. Maintaining approximately 1 mg/L NH4-N at the end of the aeration basin is critical for balancing nitrification performance and aeration energy reduction. At the same time, achieving accurate and stable measurement in this low concentration range has traditionally been considered difficult for conventional ion-selective electrode (ISE) technologies. In addition, fouling or drift of DO sensors can cause deviations between actual and measured DO concentrations, potentially destabilizing ABAC control logic and resulting in excessive aeration energy consumption or insufficient nitrification performance.
Online process sensors used in wastewater applications are frequently exposed to sludge, biofilm accumulation, and organic fouling, all of which contribute to signal drift and increased maintenance requirements. Conventional ISE ammonia sensors often experience reduced stability and increased maintenance burden in low-range applications. Meanwhile, reagent-based analyzers can provide high analytical accuracy but typically require high capital investment for sample conditioning systems, reagent handling equipment, pumps, tubing, and shelters. They also involve ongoing operating costs associated with reagent replacement, consumables, waste disposal, and routine maintenance, creating operational challenges for facilities facing limited staffing resources.
This presentation introduces field operational experiences using a low-maintenance process monitoring approach combining a low-range ISE NH4-N sensor with ultrasonic cleaning technology. Evaluations were conducted in municipal wastewater aeration basins and SBR processes to assess low-range NH4-N tracking capability, long-term operational stability, maintenance reduction, and applicability to ABAC operation.
The NH4-N sensor utilizes a proprietary ion electrode structure and compensation technology designed to improve low-range measurement stability. Evaluation results demonstrated stable response performance around the 1 mg/L NH4-N range while maintaining good correlation with laboratory and reagent-based analyzer measurements. The system also demonstrated response characteristics and long-term stability suitable for aeration control applications.
In addition, integrating ultrasonic cleaning technology significantly reduced sensor fouling and manual cleaning frequency under activated sludge conditions. Field evaluations demonstrated manual clea
In recent years, Biological Nutrient Removal (BNR) processes at municipal wastewater treatment plants have increasingly adopted ABAC (Ammonia-Based Aeration Control) strategies to improve nitrogen removal performance while reducing aeration energy consumption. In the U.S. wastewater industry, growing emphasis on decarbonization, net-zero initiatives, energy-positive utilities, and workforce shortages has accelerated the need for operational strategies that enable more stable treatment performance with less energy and fewer operator interventions. Because aeration systems typically account for 40–60% of total plant energy consumption, optimization through low DO operation combined with ABAC has become a major focus for utilities seeking sustainable and cost-effective operations.
However, successful implementation of these advanced control strategies requires reliable and stable low-range NH4-N and DO monitoring. Maintaining approximately 1 mg/L NH4-N at the end of the aeration basin is critical for balancing nitrification performance and aeration energy reduction. At the same time, achieving accurate and stable measurement in this low concentration range has traditionally been considered difficult for conventional ion-selective electrode (ISE) technologies. In addition, fouling or drift of DO sensors can cause deviations between actual and measured DO concentrations, potentially destabilizing ABAC control logic and resulting in excessive aeration energy consumption or insufficient nitrification performance.
Online process sensors used in wastewater applications are frequently exposed to sludge, biofilm accumulation, and organic fouling, all of which contribute to signal drift and increased maintenance requirements. Conventional ISE ammonia sensors often experience reduced stability and increased maintenance burden in low-range applications. Meanwhile, reagent-based analyzers can provide high analytical accuracy but typically require high capital investment for sample conditioning systems, reagent handling equipment, pumps, tubing, and shelters. They also involve ongoing operating costs associated with reagent replacement, consumables, waste disposal, and routine maintenance, creating operational challenges for facilities facing limited staffing resources.
This presentation introduces field operational experiences using a low-maintenance process monitoring approach combining a low-range ISE NH4-N sensor with ultrasonic cleaning technology. Evaluations were conducted in municipal wastewater aeration basins and SBR processes to assess low-range NH4-N tracking capability, long-term operational stability, maintenance reduction, and applicability to ABAC operation.
The NH4-N sensor utilizes a proprietary ion electrode structure and compensation technology designed to improve low-range measurement stability. Evaluation results demonstrated stable response performance around the 1 mg/L NH4-N range while maintaining good correlation with laboratory and reagent-based analyzer measurements. The system also demonstrated response characteristics and long-term stability suitable for aeration control applications.
In addition, integrating ultrasonic cleaning technology significantly reduced sensor fouling and manual cleaning frequency under activated sludge conditions. Field evaluations demonstrated manual clea