Field-scale application of artificial floating islands for cyanotoxin reduction from residential raw sewage treatment basin
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Date
2024-03
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Abstract
Microcystin (MC) stands as the most prevalent cyanotoxin associated with freshwater harmful algal blooms (HABs), posing substantial health risks to both humans and aquatic ecosystems. Artificial floating islands (AFIs) present a promising solution to MC reduction. In this study, we implemented AFIs with two native aquatic plants, Carex comosa (bristly sedge) and Eleocharis obtusa (blunt spike-rush), in the equalization basin of a wastewater treatment plant for preliminary treatment of residential raw sewage. Over three months in late summer and fall, we monitored MC concentrations, physico-chemical parameters, nutrient levels, and plant biomass. Results indicated that the AFI system reached the highest of 77.9% reduction in MC levels during the active plant growth period. Precipitation emerged as a critical factor affecting MC reduction rate in natural settings. Plant assimilation was identified as the primary contributor to MC reduction under natural conditions, given the low susceptibility to temperature fluctuations. While temperature and nutrient levels did not directly influence MC reduction rates, they impacted plant growth, thereby indirectly affecting AFI performance. Notably, C. comosa exhibited higher potential for MC reduction than E. obtusa, attributed to its rapid growth and greater biomass yields. This study is the first exploration of field-scale AFI applications targeting MC as the primary pollutant, emphasizing the viability of field-scale AFIs as a sustainable and effective strategy for cyanotoxin management.
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Poster Division: Food, Agricultural, and Environmental Sciences (FAES): 1st Place (The
Ohio State University Edward F. Hayes Advanced Research Forum)