Evaluating Biofiltration in Small Urban Areas: Chico, California Case Study

EPA Grant Number: SU835992
Title: Evaluating Biofiltration in Small Urban Areas: Chico, California Case Study
Investigators: Bronner, Colleen E
Institution: California State University - Chico
EPA Project Officer: Sergeant, Anne
Phase: I
Project Period: September 1, 2015 through August 31, 2016
Project Amount: $14,963
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2015) RFA Text |  Recipients Lists
Research Category: P3 Awards , Pollution Prevention/Sustainable Development , Sustainability , P3 Challenge Area - Green Infrastructure


As urbanization and climate change progress, more impermeable surfaces combined with intense storm events lead to increased surface water runoff. Whether runoff enters a storm water collection system or drains directly into a surface water body (e.g., lake or river), it contains primary pollutants such as sediment, nutrients, pesticides, and metals. To mitigate the adverse effects of these pollutants on aquatic ecosystems, communities are installing urban green water infrastructure such as biofiltration systems to slow runoff down and capture pollutants. As with any new technology, the practice is ahead of the science and there is a lack of evidence-based design for these systems. This project will use laboratory experiments to investigate key design criteria for developing an efficient and sustainable biofiltration system. In addition, the team will perform a life cycle analysis (LCA) on the selected biofiltration design to estimate the overall impact on the environment and local economy.


The project team will design and construct laboratory biofiltration systems out of inexpensive construction materials in Chico, a city in Northern California, which will serve as a model small urban area. Potential media to be tested include cobble, gravel, sand, lava rock, zeolite, granular activated carbon, and other media. Native, drought-resistant, sun-tolerant plants will be employed. In Phase I of the project, short-term experiments will examine physical design factors (e.g., plant density, permeability of media) and further investigate plants species suitable for biofiltration based on climate conditions. In Phase II, longer-term experiments will investigate preferred media configurations and plant types. The team will measure efficiencies of the different configurations for removing nutrients, suspended sediment, metals and select chemicals. Water used for these experiments will either be a synthetic “storm water” mixture of chemicals or storm water collected from rain events in Chico, depending on availability. Samples will be collected and analyzed at scheduled intervals. The student team will also perform a LCA to compare biofiltration with other types of storm water management techniques. Furthermore, the project team will develop a complementary educational component to disseminate knowledge about urban green water infrastructure.

Expected Results:

Results will be synthesized to identify important design considerations for biofiltration and produce a biofiltration guidance pamphlet for small cities and campuses considering this pollution prevention method. Other educational outcomes will include production of biofiltration infographics, demonstrations for K-12 outreach events, and a poster explaining the results and importance of the research project.

Supplemental Keywords:

water treatment technology, urban water planning, water filtration, pathogen removal, storm water management, ecological, hydrological, water cycle, cost benefit assessment, environmental education;

P3 Phase II:

Evaluating Biofiltration in Small Urban Areas: Chico, California Case Study