The phrase “What gets measured, gets managed” is a well-worn credo in business and, while its meaning is fairly direct — using metrics to inform decisions can produce better results — it has been criticized and even misunderstood over the years.
When it comes to direct potable water reuse (DPR), the phrase carries weight and deserves consideration as stakeholders across the United States look for ways to address current and future water scarcity issues.
DPR remains at the furthest end of the water reuse continuum but is increasingly becoming necessary for sustaining freshwater supplies for communities. When evaluating and determining benchmarks for a new project, past case studies and technology summaries can be valuable tools. They are limited, however, due to the variability from technology to technology, state to state, and even site to site.
To choose between different technologies and processes, project developers could benefit from a process or decision-making framework. One valuable tool that can help provide information to improve decision-making is techno-economic analysis that includes key performance indicators (KPIs).
KPIs can play a key role for utilities looking to make difficult decisions about future projects. Developers must know what needs to be measured in their own facility before being able to find comparable projects around the country to further investigate.
Linking Performance with Project Needs
Water reuse projects are driven by regulatory imperatives, water scarcity or consistent supply issues, or the emergence of more cost-effective solutions. The way that water reuse is implemented, however, is driven by the application of individual water reuse projects.
While industrial applications tend to focus more on the business case for application, municipal applications must put a heavy emphasis on public health and safety, education, and emotional responses.
There is currently no consistent list of reliable KPIs, though regulatory KPIs are required regardless of application. There are also currently no Environmental Protection Agency (EPA) or federal regulations for potable reuse, only state-level regulations and guidelines in select areas. These regulations and guidelines are useful, especially in measuring chemical risks and pathogen risks related to public health requirements, but there are additional KPIs for water reuse that should also be considered, including stakeholder and technology KPIs.
Stakeholder KPIs differ by application and typically indicate perceived success. Technology-based KPIs vary widely and are based on source and end-use.
Because of the various applications and stakeholder considerations, these fit-for-purpose thresholds are most likely a resource-intensive barrier for many states trying to develop water reuse KPIs. This all points to the fact that it may be more effective to outline a KPI decision framework instead. This kind of process would help compile evidence-based information to better align use and source.
How to Determine Additional Considerations
In addition to regulations, stakeholders, and technology KPIs, other indicators should also be considered. Energy demand and greenhouse gas (GHG) emissions, related to both energy consumption and implementation, should be examined at a unit-process or system-wide level. Sound energy efficiency concepts and resource recovery practices can be used to offset energy demand.
When choosing between different water recycling technologies, an important indicator can be the percentage of water recovered via reuse. Reverse osmosis (RO) and technologies that generate a brine or reject steam would compare unfavorably to others, while using a percentage of water recovered can be a useful metric for evaluating RO membranes.
Operational considerations center on the size of a facility and its surrounding community. A small community may not have enough dedicated staff members to operate and maintain a potable reuse facility. Instead, small communities and facilities may be better suited for low-input technologies and strategies, including unit operations that combine process steps and enable recycling. Because of this, potential technologies and strategies should be evaluated according to maintenance intervals and operational complexity.
Comparing various suppliers and specific technologies can result in significantly different costs of ownership to utilities. As such, the lifespan of technologies, as well as a supplier’s experience in executing successful projects, should both be on the list of KPIs. For example, some membrane suppliers may manufacture products that lack reinforcement to cut costs, but those decisions result in significant future costs to owners once the membranes begin to fail at different rates.
KPIs Driving Innovation
As we push innovation in potable recycling flowsheets, it’s important to compare how the technologies will fit together. This highlights a more generalized example of a KPI for emerging technologies.
For example, ozone combined with biofiltration in water treatment yields multiple benefits, representing a paradigm shift in comparison to RO membranes, which have high energy demand while producing brine reject. A combined ozone and biofiltration treatment offers considerable process performance potential in the removal of natural organic matter, disinfection by-product precursors, total organic carbon (TOC), and turbidity. The process also provides cost savings across treatment trains and is easily implemented.
It’s worth looking at the Research and Innovation for Strengthening Engagement (RISE) program, an approach for technology adoption that the nonprofit Water Environment Federation models through its research and innovation committee. In order to accelerate the adoption of innovative technologies in the water industry, it’s essential to integrate utilities, academics, technology developers, and consultants in a common discussion. To drive adoption, stakeholders must create pathways for investment and funding, regulatory alignment, and end-user connections.
Focus on a Collaborative Framework
Developers should focus on a KPI decision-making process rather than using standardized or “fit-for-purpose” KPIs. They should start by deciding why something needs to be measured, who needs to make the decision, and what information is necessary. Then they can determine how the KPI should be presented, how it’s defined, and what data gathering analysis method is most appropriate.
This kind of framework can be a powerful tool that considers the specific variables each facility is dealing with, from regulatory to workforce to footprint to cost of ownership. Other important KPIs could include diversity, ecosystem opportunities, or climate resilience.
When technology is adopted and aligned with more granular KPIs that account for current and potential applications, positive results can be achieved. A chosen technology should help deliver a competitive total cost of ownership, meet discreet effluent targets and downstream needs, and monitor process elements that correlate or ensure system performance. The technology should enable ease of system operation, robustness, and reliability, while supporting future reuse options. Establishing these project-specific KPIs will help drive the technology forward.
Knowing what to measure on water reuse projects will help drive the decisions of today and the solutions of tomorrow, and in a more timely and cost-effective manner. WW
About the Author: Stephen Katz is the market development manager for water technologies and solutions at SUEZ. He has worked with water and process technologies for more than 15 years.
Published in WaterWorld magazine, November 2022.
