Stormwater Recharged: Innovating with Electrical Flocculation

Discover the future of stormwater management! Join us for a presentation on our self-contained, portable stormwater treatment device. Developed through a US DOT SBIR contract, this device employs electrical flocculation technology to achieve water quality improvements without chemicals, pumps, or filters. With a significant reduction in pollutants like TSS, heavy metals, and nutrients it's a scalable, versatile solution for construction and post-construction stormwater runoff challenges. In our upcoming session, we'll discuss the design, construction, and testing conducted in Phase I and unveil plans for Phase II, focusing on device refinement and enhanced capabilities. Don't miss this opportunity to learn about the next generation of stormwater solutions!

Full Abstract: Stormwater management is integral to the design and operation of roadways to mitigate the impacts transportation infrastructure has on water quality and to assure compliance with state and federal regulations. State department of transportations (DOTs) are challenged with the obligation to maintain and preserve local environmental systems while maintaining a safe, reliable, and cost-efficient transportation system. The construction, operation, and maintenance of roadways generates pollutants such as sediment, heavy metals, and nutrients; pollutants which the U.S. Environmental Protection Agency (USEPA) identifies as the most widespread in impeding the beneficial uses of the Nation’s rivers and streams. Today, 80% of the U.S. population lives in areas regulated by municipal separate storm sewer system (MS4) permits. These areas are required to implement measures to address water quality and quantity impacts. Despite decades of regulatory action, over half of our nation’s assessed water ways are listed as impaired or threatened from urban non-point source runoff. Increased urban runoff pollution coupled with aging systems earned Stormwater infrastructure a letter grade of “D” on the 2021 American Society of Civil Engineers Infrastructure Report Card. Therefore, a need exists to develop enhanced stormwater management practices that are easy to employ and maintain while minimizing potential for other pollutant concerns associated with treatment measures.
Through a Small Business Innovation Research (SBIR) contract with the US DOT, Fagan Consulting LLC, in partnership with Auburn University, is developing a self-contained, portable stormwater treatment device. The device employs electrical flocculation technology to meet desired water quality goals. This innovative device, similar to electrocoagulation systems in water and wastewater treatment, harnesses electrical current to induce the formation of flocs from suspended contaminants, thereby enhancing settling and removal efficiencies. This process achieves the effectiveness of chemical flocculation without the use of chemical compounds, pumps, or filters. Further, the “electrical floc generator” operates effectively using 12 volts of power. Its design allows for versatile applications – it can be a standalone, battery-powered unit for mobility or be integrated into a fixed location with an external power source. Additionally, the scalability of the device enables it to handle larger flows and pollutant loads effectively, making it a valuable tool for stormwater management practices. This flexibility makes it an ideal solution for a variety of settings, from construction sites to post-construction environments.
Significant findings from the assessment of the electrical floc generator's capabilities show its effectiveness in treating a diverse array of pollutants, encompassing total suspended solids (TSS), nutrients, heavy metals, and beyond. Data collected from preliminary testing shows over a 70% reduction in TSS, iron, copper, and lead. Similarly, these results yielded over a 60% decrease in cadmium and phosphate. Testing conditions consisted of a 10GPM flow rate, a passive mixing mechanism, and 30 minutes of settling in a lamella settler. These findings prove the device's versatility and efficacy in addressing a broad spectrum of environmental contaminants. Further, spectrophotometer testing was conducted to assess the amount of dissolved aluminum (Al3+ ions) that would be released using the electric floc generator, under the same testing conditions. Results from the spectrophotometer testing showed 0.22 mg/L of dissolved aluminum was found in the effluent of our samples. The EPA specifies a maximum concentration of 0.20 mg/L for Al3+ ions in drinking water.
Our team will begin the two-year Phase II of the SBIR contract in the summer of 2024. We will focus on device refinement, PFAS and 6PPD-quinone removal testing, photovoltaic power integration, and automation of controls.