Problem to Product: Evaluating the Use of Stormwater Pond Algae to Bioremediate Ponds and Generate Compost
While stormwater ponds are an effective best management practice for reducing stormwater runoff, often the algae that accumulates in them is considered a nuisance. Traditional treatments such as copper-based algaecides are not environmentally friendly, and other methods of removal can be costly and time consuming. Additionally, algae has a high capacity to remove contaminants from the water, a process called phycoremediation. This study aims to evaluate the viability of utilizing stormwater pond algae as a vermicompost feedstock, using what would be waste to improve water quality in the ponds and the water bodies they feed into and turning it into an environmentally and economically friendly product. Two phases of study were conducted. First, a mesocosm experiment to quantify uptake of nickel, copper, zinc, cadmium, lead, and mercury by the algae was conducted. Results of the study revealed a 150-185% decrease in metal concentrations in the tanks that contained algae compared to control tanks that contained no algae. Next, two rounds of compost studies were conducted to establish the algae as a viable compost feedstock and to evaluate the metal concentrations of the final product. While feedstock viability was supported, tests for the metal concentrations in the final compost product were inconclusive. Analysis of the input materials suggests final concentrations can exceed European Union limits for heavy metals in compost. Further studies are planned to determine the safety of the compost. If found to be safe, removal and composting of algae from stormwater ponds could be an effective, eco-friendly, and even lucrative alternative to traditional algae treatments.
Phoebe is a senior at Virginia Wesleyan University pursuing her Bachelor of Science in Earth and Environmental Sciences while working part time for The Elizabeth River Project as an administrative assistant. She hopes to pursue a master’s degree in an environmental policy program after graduation. She is also a 2020 recipient of the VLWA Leo Bourassa Scholarship.