Phytoremediation of the Des Plaines River

Abstract

The problem of contaminated waterways is an inclusive issue. A 2018 United States water quality survey showed nearly half of the rivers and streams, and more than one-third of lakes are polluted and unfit for swimming, fishing, or drinking. The research scope of this thesis was to propose and evaluate phytoremediation methods for bacteria, nitrogen and phosphorous, metals, and dissolved oxygen in the Des Plaines River in the Gooselake watershed of Illinois. The first objective of this study was to identify appropriate actionable remediation methods for bacteria, nitrogen and phosphorous, metals, and dissolved oxygen in the Des Plaines River. This was done by modeling a general approach of evaluating prior phytoremediation and wastewater treatment studies. The second objective was to provide recommendations that can be utilized by decision makers to support the remediation of this waterway. The remedial effectiveness, environmental impact, and cost benefit were determined for each proposed option. Methods for this study included analysis of prior case studies, environmental impact, and fiscal feasibility. I hypothesized that phytoremediation for the top contaminants found in the Des Plaines River could offer the same contaminant removal rate as a capital wastewater treatment plant. Furthermore, I hypothesized that phytoremediation for the top contaminants found in the Des Plaines River can offer a financial benefit of 70% lower investment and operating cost when compared to a wastewater treatment plant. This research provided insight on the effectiveness of remediation methods for cleaning up prevalent contaminants found in the Des Plaines River. As an outcome of this research, a possible policy was developed for government agencies and permit holders. The recommendation is that phytoremediation be included as a best practice for the National Pollutant Discharge Elimination System (NPDES) and municipal separate storm sewer systems (MS4) permit holders. The effectiveness of Typha species was especially promising as it could streamline the initiative, making it cheaper and easier to apply. The results of the environmental impact study showed that phytoremediation is an effective long-term remediation option, engages the community, and is less environmentally damaging. The overall effectiveness of phytoremediation is based on the customization of each application. Depending on the scope of time and application size, phytoremediation can be more effective than a wastewater treatment plant for nitrogen, phosphorous, aluminum, and arsenic removal. The rate at which contaminants could be removed remains dependent on factors such as growing conditions, scope of application, and combination of plant usage. It was determined that a wastewater treatment plant is more effective at increasing dissolved oxygen, and remediating lead and bacteria. The cost benefit analysis showed that the cost for disposal is equal for phytoremediation and a wastewater treatment plant. However, phytoremediation showed significant cost savings for capital, staffing, and potentially operation and maintenance expenses.