There will always be challenges of running a wastewater utility. Adapting to the ever-changing regulatory requirements, costs of operations and maintenance, and, more recently, a diminishing workforce, continues to be a challenge for a utility manager. The City of Modesto was able to convert challenges into opportunities, but it wasn’t a clear cut path. It took outside-the-box thinking and taking calculated risks that positioned the City to take advantage of opportunities that led the road to success.
Too often we hear “this is the way we’ve always done it”, which is a common excuse to avoid any potential changes, and, with it, some associated anxiety to an established process. In Modesto’s case, a new National Pollution Discharge Elimination System permit requirements compelled the City to upgrade its straightforward secondary wastewater treatment process (which, until this point, had been operated the same way for over 30 years) to meet the more stringent discharge requirements for nutrient removal and tertiary treatment. To do this, the City would be looking at substantial financial investment in terms of equipment and staffing costs.
In order to get early buy-in, the operations and maintenance staff were included in the discussions with the engineers from the outset. Anticipating the changes to regulatory landscape, City team committed to a relatively new technology called Membrane Bioreactors (MBRs), versus a traditional tertiary treatment system. MBRs are considered a state-of-the-art microfiltration process which also has a high degree of automation and reliability. In terms of technological advances, the magnitude of complexity can be compared to upgrading a proverbial propeller-driven airplane with a jet engine. Paired with a biological nutrient removal process, an MBR system produces a very high quality of effluent that exceeds the regulatory water quality requirements.
In less than 10 years, Modesto has invested over $150M in two state-of-the-art wastewater facilities that will treat up to 14.9 million gallons per day of tertiary (recycled) water. Despite a steep learning curve, staff has embraced the new treatment system, and has reinvigorated interest in careers in wastewater operations at the City. Staff has an immense sense of pride operating these facilities that not only helps the environment, but the resulting recycled water has become an essential component for regional drought resiliency.
"Too often we hear “this is the way we’ve always done it”, which is a common excuse to avoid any potential changes, and, with it, some associated anxiety to an established process"
The recycled water produced by the City’s facilities is a major component of one of the largest beneficial reuse projects in the United States. The term “Whiskey is for drinking, Water is for Fighting” is very true in here in California’s Central Valley, where water is the life blood of a multi-billion dollar agricultural industry in the region. The City recently completed a $50M portion of an innovative recycled water delivery project, the North Valley Regional Recycled Water Program, which will ultimately provide over 25 million gallons per day to a nearby irrigation district. Recycled water is drought-proof, and provides the irrigation district an assured water supply that they did not previously have. As a result, the project is currently generating revenue for the City through the sales of recycled water.
The success of this program can be attributed not only to the City taking the calculated risks with constructing a high-tech facility, but also investing in what ultimately resulted in a timely project that produces a revenue-generating water resource that benefits the region.
Rebecca Delaney, P.E., Associate Director and Operations Leader for Sustainable Engineering Studio, and Luke Leung P.E., ASHRAE Fellow, LEED Fellow, BEMP, P Eng, Director of Sustainable Engineering Studio, Skidmore, Owings and Merrill