Developing and Implementing Tools for Small Systems to Evaluate and Select Appropriate Treatment Technologies

Water utilities can struggle to know which treatment technologies to consider and then which one to select and implement to solve their water quality and compliance challenges. This is particularly challenging for small water systems without resources to stay up-to-date on the range of appropriate technology options and their associated treatment and operational performance. The DeRISK Center is dedicated to addressing this challenge by developing and implementing tools for small systems to evaluate and select appropriate treatment technologies. These tools are designed to help utilities, states, consultants, and technology providers make technology selection decisions based on public health protection and sustainability beyond just regulatory compliance.

A conventional analysis of technology alternatives is typically performed when water systems need to upgrade or replace major treatment facilities. This analysis consists of identifying the feasible alternatives that will accomplish the treatment goals, comparing the alternatives based on some criteria, and selecting the “best” alternative. The criterion most used is cost—capital cost, operation and maintenance cost, or an engineering life-cycle cost analysis that includes the anticipated life-span of major equipment.
 
The DeRISK Center tools employ a decision support methodology that improves on this conventional approach. The major steps in the methodology are deciding what criteria are most important to stakeholders and providing and easy way to compare technology alternatives to each other with respect to each criterion. Our approach strives to go beyond just a comparison of costs. As shown in Figure 1, the decision support methodology expands on the conventional analysis of alternatives process by including:

• Facilitated methodology that incorporates stakeholder input
• Data on innovative treatment technologies
• Relative health risk protection of treatment approaches
• Sustainability measures of treatment approaches
• Stakeholder preferences

Performance information such as treated water quality and performance data along with other characteristics, including source water quality constraints, are used to identify feasible technology alternatives. The characteristics for feasible alternatives are then fed into the analyses of health risk, sustainability, and stakeholder preferences in order to provide data to the decision support methodology.  
 
Microbial and chemical agents in drinking water can pose significant human health risks. Evaluating the combined impacts from multiple contaminants can provide new insights into how best to manage that risk and protect public health to meet regulatory compliance and achieve the greatest risk protection possible given feasible alternatives. The DeRISK Center tools utilize the Relative Health Indicator (RHI)—a semi-quantitative metric developed to harmonize the cancer and non-cancer impacts from a wide range of drinking water contaminants—to compare the relative health risks posed by multiple waterborne constituents.
 
The DeRISK Center is also focused on analyzing and improving the environmental and economic sustainability of small drinking water treatment systems. To achieve this, life cycle analysis (LCA) methodology is being used to quantify and characterize environmental impacts associated with various drinking water technologies. These impacts (using EPA’s TRACI assessment method) include ozone depletion (kg CFC-11 eq), global warming (kg CO₂ eq), smog (kg O₃ eq.), acidification (kg SO₂ eq.), eutrophication (kg N eq.), carcinogenics (CTUh), non carcinogenics (CTUh), respiratory effects (kg PM 2.5 eq.), ecotoxicity (CTUe), and fossil fuel depletion (MJ surplus). A comprehensive LCA model framework was developed utilizing water treatment data, experience, and commercial information.
 
Last, the DeRISK Center is putting these tools to the test evaluating treatment technology decisions through cases studies with actual small water systems needing to address water quality and compliance challenges. The first case studies are assessing disinfection alternatives for small water systems in New Hampshire. 

If you are interested in testing these tools and collaborating with DeRISK Center researchers to assess treatment technology alternatives for your water system, please contact Chad Seidel at chad.seidel@colorado.edu.