Cultivating a Culture of Innovation

Full article as it appears in the April 2024 edition of Water Environment & Technology (WE&T) magazine

How planning, partnerships, and perspective can help de-risk emerging technologies 

Innovating existing processes and approaches often represents a challenge in the justifiably risk-averse culture of water resource recovery facilities (WRRFs). However, during an age in which new threats and stressors on WRRFs mount at a speed matched only by the rise of new technologies, continuous innovation is a must for any WRRF that intends to serve its customers and protect its surrounding environment effectively.

The Four Rivers Sanitation Authority (FRSA; Rockford, Illinois), which provides wastewater services to a service population of approximately 240,000, has demonstrated during its 90-year history that the best ways to approach innovation are both proactive and organizationwide. Championing adaptive planning, applied research, and demonstration testing, FRSA has forged a true culture of innovation that promises to keep processes sustainable and expand facility capacity well into the future.

Creating this culture of innovation requires considerable work and thoughtful planning but remains attainable for WRRFs of all sizes and resource levels. It demands a robust approach to research, a willingness to form partnerships that minimize the risks of incorporating new tools and approaches, new ways of planning infrastructure that leave room for future improvements, and — perhaps most importantly — leadership that keeps an open mind toward new ways of doing things.

As FRSA’s success shows, a culture of innovation can enable WRRFs to not only meet or exceed operating and permit requirements, but also minimize costs for customers and benefit the broader water sector by demonstrating the value of emerging technologies.

Streamlining Technology Review

Energy efficiency and sustainability are two of FRSA’s highest priorities in the technologies it has pursued within the past few decades. These longstanding goals are top-of-mind in the agency’s approach to facility design and construction.

In line with broader efforts to promote biosolids processing, FRSA incorporated anaerobic digestion and associated gas-recovery-and-reuse systems into its WRRF processes during the 1990s. To further enhance the benefits of these systems, in the early 2010s, FRSA explored the viability of increasing biogas production in the anaerobic digesters by importing and codigesting high-strength wastes (HSW) and fats, oils, and grease (FOG). Evaluations found that excess digester capacity was available for codigestion, adequate supplies of HSW and FOG existed in the area to support such a program, and an economic business case showed a return on investment within 5 to 7 years for required new construction. In addition, implementing this program would provide energy-resilience and sustainability benefits to FRSA operations. FRSA proceeded with new facilities for HSW and FOG receiving and holding, as well as improvements to biogas-handling systems and heat recovery from cogeneration units.

With these improvements in place, FRSA estimates that approximately 71% of its campus’ energy needs are met through onsite generation, saving customers approximately USD $1 million annually compared to purchased power.

In the mid-2010s, FRSA staff began investigating ways to optimize energy consumption during mixing in secondary treatment aeration basins. As with many such systems designed and implemented in the preceding decades, existing measures to drive aeration were inefficient, demanding more energy to supply more air to the system than what was needed to support the biological process. This use of pressurized air solely to provide mixing energy is generally 25% to 50% less efficient compared to mechanical mixing, with similar inefficiencies when using process air instead.

frsa digests wastewater

The analysis showed that mechanical mixing methods such as hyperbolic impellers — then an emerging technology for wastewater-mixing applications — could reduce energy consumption significantly as well as increase the lifespan of aeration equipment by reducing the number of necessary operating hours for the blowers. Based on these findings, FRSA implemented hyperbolic impeller-type mixers within the aeration basins.

Elsewhere on the FRSA campus is the Graceffa Administration Building, named after former FRSA Executive Director Steve Graceffa. Constructed in the late 2000s, the 3,700-m2 (40,000-ft2) building is emblematic of how FRSA leadership and staff embrace sustainability measures. It received a Leadership in Energy and Environmental Design Silver Certification in 2009. Factors that led to the award included construction materials used; construction debris disposal processes; and how the building is heated, cooled, and lit. This includes using residual heat from the cogeneration process to heat the building during cold months. The administration building also features seven rain gardens to reduce and reuse stormwater runoff, which, like all landscaping throughout the FRSA campus, is irrigated with reclaimed water from the WRRF.

FRSA’s process of designing and upgrading its facilities demonstrates the value of comprehensive comparison between different technologies, as well as the importance of remaining open to unconventional approaches. Key to this process was developing a formal relationship in 2011 with a technology vendor to facilitate onsite research into innovative technologies. The partnership was a win-win proposition, enabling FRSA to minimize its technology assessment costs while providing the vendor with a useful testing site to examine how its technologies would perform under real-world wastewater treatment scenarios.

The vendor constructed a research and technology center on the FRSA campus, where researchers studied the potential of cloth media filtration for advanced primary treatment, among other innovations. In 2017, they designed and commissioned a 760,000-L/d (200,000-gal/d) demonstration facility for aerobic granular sludge (AGS) technology at the FRSA site, the first facility of its kind in North America.

Research Informs Present and Future

FRSA continues to build upon its culture of innovation as the agency contends with current and future priorities. In 2018, the organization began a new facility-planning effort, which set goals for nutrient removal, flexible capacity for growth, resource recovery, and addressing aging infrastructure.

settling tests for wags seeding

Nutrient-removal goals focused on known future total phosphorus and reasonably expected future totalnitrogen limits, and how potential capital improvements could build upon one another to meet low-level limits. Flexible capacity for growth considered how upgrades to FRSA facilities could best position the agency to accommodate any fast-developing regional economic opportunities afforded by new industries entering the area. Resource recovery goals sought to build on FRSA’s existing momentum, such as its HSW facilities for biogas production and cogeneration, to develop recovery solutions that fit within a circular economy approach. Finally, the facility plan aimed to prioritize investments that capitalized on existing facilities as part of future improvements while also strategically planning for retirement or replacement of aging infrastructure.

FRSA’s facility plan sought not only to identify new technologies to help meet these goals, but also to investigate the optimal ways to integrate them into existing systems. For that reason, the investigation process entailed an applied research plan that guided efforts to study how emerging technologies could affect capital and operating costs during their implementation, as well as whether these improvements could create new opportunities for collaboration with water sector partners.

frsa and a technology

For example, the plan outlined key research questions related to AGS implementation and whether seeding of granules into the activated sludge process would improve settleability. As a result, during preliminary design of the AGS facilities, FRSA performed settling tests using a combination of waste activated sludge (WAS) and waste aerobic granular sludge (WAGS) from the onsite demonstration reactor. FRSA observed an increase in settling velocity with the WAGS-WAS mixture, indicating improved settleability and thus improved clarifier capacity with seeding (see Figure 1, p. 33).

From Research to Implementation

As FRSA moved toward the implementation phase, insights from the agency’s robust approach to research helped it prioritize investments according to its most pressing needs, settling on three major capital improvement projects: clothmedia primary filtration, AGS, and biological nutrient removal (BNR).

The primary filtration project consists of adding cloth-media disc filters designed to treat 114,000 m3/d (30 mgd) to replace and enhance primary clarifier capacity without affecting the footprint of the process. Given FRSA’s extended experience working with the technology vendor in their onsite research facility, it was able to proceed with sitespecific demonstration testing to inform design decisions and anticipated performance. Primary filtration also provides an added energy benefit. The increased primary solids capture and subsequent diversion to anaerobic digestion will increase biogas production (see Figure 2, p. 34).

secondary treatment

FRSA’s new AGS facilities, initiated in 2021, add 38,000 m3/d (10 mgd) of secondary treatment capacity. By combining rapidly settling granules with a single, semi-continuous flow reactor system, an AGS facility can achieve nearly double the capacity per footprint when compared to a conventional activated sludge system (aeration basin plus final clarifiers), of which AGS represents the next evolution. For FRSA, AGS intensified secondary treatment to maximize treatment capacity within the existing site footprint (see Figure 3, above).

The AGS facilities at FRSA will operate in parallel to the activated sludge process, receiving effluent from the primary filtration facilities and discharging upstream of disinfection. In anticipation of future capital improvements related to BNR, the AGS facilities were designed to discharge solids back to the activated sludge process. Onsite settling tests, as previously described, confirmed settling improvements associated with seeding of waste AGS solids, thereby increasing clarifier capacity. By taking advantage of this wastestream and proactively looking forward to other planned projects, FRSA will increase secondary clarifier capacity with minimal additional capital during the AGS project.

The eventual scope of BNR improvements includes modifications to existing aeration basin tanks to incorporate selector zones as well as addition of sidestream fermentation facilities and selective wasting facilities. To inform sidestream fermentation basis of design, FRSA performed bench-scale apparent fermentation rate testing on mixtures of return activated sludge and primary sludge (see Figure 4, p. 35).

construction is progressing

Based on the results of the testing, FRSA decided to phase implementation of BNR improvements. The initial phase, currently under design, focuses on aeration basin conversion to the modified University of Cape Town BNR process. This phased approach allows further evaluation of expected process performance for the planned selective wasting and sidestream fermentation facilities, taking into account primary filtration and AGS facility performance once online.

The BNR improvements also include advanced aeration controls that will incorporate a simultaneous nitrification-denitrification process to optimize nutrient removal and energy efficiency.

construction of aerobic

Each of these projects will build on each other to enable FRSA to meet its long-term nutrient-removal goals and future effluent permit compliance (see Figure 5, p. 36).

Tips for Successful Technology Adoption

Over several decades, FRSA has invested time and resources into investigating new technologies and planning for the phased implementation of capital improvements to better serve the long-term needs of its customers. Following FRSA’s example, other utilities also can take steps to create a true culture of innovation.

  • Take advantage of regulatory timelines for testing and investigation. Rather than delay making improvements for nutrients and capacity, FRSA began demonstration testing and studies nearly 20 years before the ultimate regulatory timeline. By taking advantage of the timeline provided, FRSA could test primary filtration, AGS reactors, and BNR configurations that ultimately reduced capital costs and will result in a more sustainable facility. FRSA was able to mitigate any sustained risks of the new technologies via testing and research.
  • Phase implementation for operational training, understanding, and optimization. An advantage of the phased, adaptive approach to technology implementation is the opportunity for operations staff to better understand each unit process change in a stepwise fashion, rather than having to manage changes to every facility all in one large project.
  • Cultivate an innovation culture. Culture is the key to innovation, and from executive leadership to entry-level operations staff, FRSA has an inquisitive culture that perpetuates innovative thinking and actions.

Contributing Authors:

Christopher Baer is Director of Engineering, Greg Cassaro is Director of Plant Operations, and Julie Scott-Valdez is Director of Management Services at Four Rivers Sanitation Authority (Rockford, Illinois). Leon Downing is Global Practice and Technology Leader for Nutrient Removal and Recovery and Director of Innovation Platform for Treatment Solutions in the Madison, Wisconsin, office, and David Koch is Project Director and Jennifer Loconsole is Process Engineer in the Chicago office of Black and Veatch (Kansas City, Missouri).