Urban stormwater is a significant contributor to impaired water quality in receiving waters. Contaminated roadway runoff may cause various adverse effects to aquatic species, ranging from sublethal impacts to acute toxicity. Stormwater treatment technologies are often installed to address such water quality challenges. However, performance of many treatment technologies is only evaluated or optimized with regulated parameters, and little is known with respect to performance for removal of broader suites of contaminants, long-term performance, or effectiveness for protection of aquatic organisms. In this study, we evaluated the roadway runoff treatment performance of compost-amended bioswales (CABS) in both laboratory and field conditions. The field CABS was a 100 ft full-scale system on State Route 518 (SR518) in SeaTac, WA, and the lab CABS was a 48 ft triplicate laboratory system constructed at the Washington Stormwater Center (WSU-Puyallup, Puyallup, WA), treating the runoff from SR520 of Seattle. Over 3 years, we collected 9 sets of samples from the field CABS during storms and 8 sets of samples from the lab CABS, and compared the contamination profile in untreated and treated runoff samples to assess the performance. We collected samples at different lengths and flowrates in the lab system to analyze the removal mechanisms. We measured regulated parameters and target contaminants, including TSS, Cu, Zn, PAHs, and phthalates, and we used high-resolution mass spectrometry (HRMS) to conduct a non-target analysis, characterizing the removal of a broad range of organic contaminants. The results showed that longer swale length and longer hydraulic retention time (HRT) improved contaminant removal. The removal mechanisms of contaminants varied according to the properties, and hydrophobic sorption and ion exchange were the primary removal mechanisms. In general, the removal rates of non-polar organics were satisfactory, but in consistent removal of dissolved metals were observed. 6PPD-quinone, a recently discovered toxicant that kills coho salmon, was efficiently (&gt;80%) removed in both laboratory and field CABS system.

Evaluating the removal of stormwater contaminants in compost amended bioswales using target and non-target analysis

ACS Spring Meeting 2021

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