Water has become increasingly scarce in recent years. This is due to a multitude of factors, including extreme weather events and the growing population. These unique challenges demand adaptability, necessitating a more deliberate approach to water usage and compelling us to reuse and recycle this precious resource.

Can we engineer our way out of this problem? The answer is complicated. There is no single solution; several options need to be explored, including proper infrastructure and proactive planning for the future of water treatment, with consideration for its impact on future generations.

Ankur Talwar, area manager of PCL Construction, explains how PCL’s approach to water projects sets it apart from its competitors. “We invest significant time building relationships with consultant partners and finding solutions that meet their specific needs,” he says. “PCL is more than just a builder: we are an integral part of the solution.”

In San Luis Obispo, California, PCL’s solution-provider approach is on full display — helping ensure a safe, sustainable supply of water while benefitting the local community in a multitude of ways.  

The San Luis Obispo Water Resource Recovery Facility has represented sustainable water management for more than a century, and it plays a crucial role in addressing water scarcity. In 2014, the State Water Board issued a new permit to the City of San Luis Obispo that required them to upgrade the treatment process to remove certain pollutants, such as nitrate and trihalomethanes.

Recognizing the need to rethink water reuse, the City partnered with various firms to enhance the facility over several years, and ultimately chose PCL as its leading contractor. Now, after a nearly decade-long effort by the City of San Luis Obispo, partner agencies and dedicated residents, the plant has undergone an extraordinary upgrade.

The facility upgrade enhances its current treatment process with a series of clarifiers, significantly reducing its environmental footprint and improving wastewater treatment efficiency using membrane bioreactors. The innovative membrane bioreactor treatment is a key feature that sets this facility apart. This upgrade not only enhances the plant's efficiency but also meets the long-term water supply needs of the area. While the reused water is not potable, it meets Title 22 long-term goals by improving the ability to produce higher quality recycled water usage for various irrigation purposes in everyday necessities such as parks and schools. PCL also incorporated other upgrades, including world-class equipment requiring less space and fewer chemicals, that lay the foundation for more flexible water reuse solutions in the future.

Jon Merryman, PCL project manager, says, “Upgrading secondary treatment from traditional clarifiers to MBR and coupling this with UV disinfection enables greater water reuse – not necessarily for potable purposes initially, but for non-potable Title 22 water. By reusing this water for various irrigation purposes, the demand on the potable system is reduced, creating a more sustainable and capacity-rich potable water system. The San Luis Obispo Water Plus upgrade allows the city to meet regulatory requirements while reducing potable water consumption in favor of non-potable Title 22 reuse water.”

While the City addressed the removal of pollutants, it also recognized that all easily accessible water sources have been explored. It could no longer rely solely on surface water reservoirs. This challenge, however, also presented the community with the opportunity to build enhanced systems and expand their treatments. That’s why the San Luis Obispo Water Resource Recovery Facility was designed to recycle and reclaim water for the most efficient use, not just in the short term but for decades to come. The advanced purification technology implemented in the upgrade will deliver high-quality water for future generations.

Patrick McGrath, Water Resource Recovery Facility supervisor for the City of San Luis Obispo, says, "The City's active involvement in both design and construction over the last three years has made a significant impact. We achieved and maintained regulatory compliance throughout the project through strong collaboration and transparency between the City and PCL."

Water facilities must be prepared for the increasing frequency of extreme weather events such as droughts and high precipitation. To address this, the PCL project team and the City of San Luis Obispo took decisive steps to ensure the Water Resource Recovery Facility’s preparedness. The upgraded facility provides enhanced protection for the community and improves resilience in the face of natural disasters and unpredictable weather. The increased water reuse capabilities enable the facility to withstand water scarcity during droughts by treating and reusing wastewater for non-potable purposes like irrigation or industrial processes. Similarly, during periods of excessive rainfall, the facility efficiently manages and treats the increased wastewater volume, preventing overflow and minimizing environmental hazards.

"We’re witnessing a common pattern of five to six years of drought followed by extreme rainfall,” Talwar says. “With our ability to withstand these periods being crucial, our infrastructure must adapt. During dry periods, we need to sustain water needs through storage and additional water reuse. The wastewater industry, particularly in the Southwest, has been adapting by building around this infrastructure and planning for extreme weather events. On the other hand, during large storms, additional flood protection requirements are necessary. This calls for increased capacity in our water treatment and wastewater treatment plants to address these extreme needs. It requires thoughtful and proactive thinking due to its various impacts."

The Water Resource Recovery Facility’s upgraded filtration and treatment processes effectively remove pollutants and pathogens from wastewater, significantly reducing the risk of waterborne diseases and illnesses. This ensures the safety and reliability of the community's water supply, even during extreme weather events like storms, fires and earthquakes.

The upgraded facility enhances protection against extreme weather and provides a higher-quality water supply, while also significantly benefiting the environment. It now supplies cleaner water for reuse, improving water quality and reducing the volume required for landscape irrigation. The upgraded treatment process is expected to reduce chemical usage by 80% compared to the previous method, reducing salt levels in local groundwater basins and waterways. Additionally, the facility discharges higher-quality water into San Luis Obispo Creek and Avila Beach, and the increased on-site biogas production helps offsets its energy demand, promoting greater energy renewal.

McGrath says, "The work we're doing on this upgrade is setting us up for future success. The infrastructure we're putting in place right now is building a more resilient future in the face of a changing climate."

Beyond providing sustainable solutions and advanced technologies, the Water Resource Recovery Facility actively supports community education and contributes to the well-being of San Luis Obispo and California communities. The upgrade improves odor control throughout the facility and offers valuable educational opportunities by creating partnerships with local businesses and fostering higher education in clean water initiatives. Local workers performed an impressive 77% of all labor hours, demonstrating the commitment to support the local community.

The San Luis Obispo Water Resource Recovery Facility stands as a shining example of sustainable water management, driven by resilience, technological advancements, environmental restoration, and community empowerment. It leads us toward a future where water resources are cherished and responsibly utilized, ensuring a brighter and more sustainable future.

Talwar says, “The upgrade to the facility ensures the public can sleep at night knowing that they have a plant that functions very well in extreme events, whether extreme dry periods or extreme floods. It’s been a great honor to partner with the City of San Luis Obispo on constructing such an impactful facility. It’s future-thinking and will have a positive impact on the generations to come.”

To learn more about the San Luis Obispo Water Resource Recovery Facility, visit here.

To learn more about PCL’s water-reuse solutions, visit here.