Brockton, MA, wastewater facility achieves 45% energy savings with innovative sensor technology

Xylem’s YSI IQ SensorNet is helping wastewater facilities get more from their existing systems. At the Brockton Advanced Water Reclamation Facility (AWRF), a network of YSI sensors enables advanced control of both ammonia-based and dissolved oxygen, giving the Veolia team who manage the facility the real-time insight they need to fine-tune treatment without costly infrastructure upgrades. The result: lower energy use, reduced costs, and better protection of local water resources.

In 2011 the Environmental Protection Agency deemed the Salisbury Plain River impaired (EPA, 2011). Later, the agency issued an even stricter nitrogen discharge limit of 3 mg/L (EPA, 2015). In response, the utility set out to enhance its aeration system with smarter, sensor-enabled technology. A key component of that upgrade was to transition from dissolved oxygen to ammonia-based aeration control.

What is the difference between ammonia-based and dissolved oxygen aeration controls?

Both ammonia-based aeration control (ABAC) and dissolved oxygen (DO) control systems rely on real-time sensor data to guide treatment. But where DO control seeks to maintain a static oxygen level, ABAC uses ion selective electrode (ISE) sensors to monitor ammonia concentrations – dynamically adjusting aeration based on actual conditions.

These dynamic adjustments result in better flexibility, great efficiency, and more sustainable performance.

How did Brockton AWRF improve aeration with available state funding?

To maximize the impact of available Clean Water State Revolving Fund dollars, Brockton AWRF implemented a hybrid aeration strategy. The team deployed a suite of sensors to enable ABAC in four of its seven aeration basins, while enhancing the existing DO control system in the remaining three tanks. The phased approach enables the plant to drive energy savings now and lay the groundwork for a full ABAC rollout as resources become available.

“The city wanted to get the most from the plant upgrade and available investment dollars,” said John Downey, Veolia instrumentation technician at Brockton AWRF. “By deploying ammonia-based controls where they could, while optimizing the existing DO control system, they improved performance, maintained compliance and stayed on budget.”

After a rigorous evaluation process, Brockton AWRF chose Xylem’s YSI IQ SensorNet for its accuracy, ease of use, and support offerings. The utility installed 52 advanced sensors, including ammonium ISE, dissolved oxygen, pH and UV-nitrate sensors, along with a controller platform to monitor and fine-tune nutrient levels in their aeration tanks.

Throughout the entire process, the YSI service team partnered with Veolia on implementation, sensor location, and maintenance to achieve optimal sensor measurement and control.

“The city took a very thorough approach to testing and comparing the sensor and control technologies on the market,” said Downey. “YSI stood out because of the ease of use, performance and resilience of the product. I especially like the ion-selective electrodes – they seem impervious to pain in everyday use. In testing, the IQ SensorNet system told a better story.”

Brockton AWRF achieves 45% energy savings with ammonia-based controls

Over a six-month period, four of seven of the plant’s aeration basins were brought online with ammonium-based aeration control, while the remaining three continue to use DO, with new YSI DO sensors. In June of 2024, Brockton performed a month-long study comparing the performance of its ABAC and DO systems. The findings were clear: the ABAC-enabled basins used 45% less energy per MGD of wastewater treated, nearly twice the efficiency of the DO system.

“The energy savings shown in the study surpassed our expectations and reinforces the decision to try ammonia-based controls, and transition to a full ABAC system in the future, as budget allows,” said Downey. “It goes to show you can innovate and leverage proven technologies, even with limited resources.”

Brockton AWRF plays its part in helping river maintain EPA’s “unimpaired” assessment

With a data-driven approach and support from Xylem’s advanced sensor technology and services, Brockton AWRF is optimizing its aeration system while keeping operational costs in check. By upgrading just part of the plant, the team is already achieving significant energy savings, enhancing performance, and delivering high quality effluent – all without a full infrastructure overhaul.

Brockton’s efforts are also making an impact on the community. The river, classified as impaired, is currently considered unimpaired at the point of discharge and downstream by the EPA. This means that the plant is releasing water into the river that is cleaner than the river itself.

“Smart investment delivers results,” said Downey. “With the right strategy and technology, we’re improving treatment, saving energy and protecting the Taunton River Watershed. That’s something we’re incredibly proud of.”