Browsing by Author "Sharma, Manan"

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    Biochar and zero-valent iron sand filtration simultaneously removes contaminants of emerging concern and Escherichia coli from wastewater effluent
    (Biochar, 2023-07-19) Zhu, Linyan; Chattopadhyay, Suhana; Akanbi, Oluwasegun Elijah; Lobo, Steven; Panthi, Suraj; Malayil, Leena; Craddock, Hillary A.; Allard, Sarah M.; Sharma, Manan; Kniel, Kalmia E.; Mongodin, Emmanuel F.; Chiu, Pei C.; Sapkota, Amir; Sapkota, Amy R.
    Advanced treated municipal wastewater is an important alternative water source for agricultural irrigation. However, the possible persistence of chemical and microbiological contaminants in these waters raise potential safety concerns with regard to reusing treated wastewater for food crop irrigation. Two low-cost and environmentally-friendly filter media, biochar (BC) and zero-valent iron (ZVI), have attracted great interest in terms of treating reused water. Here, we evaluated the efficacy of BC-, nanosilver-amended biochar- (Ag-BC) and ZVI-sand filters, in reducing contaminants of emerging concern (CECs), Escherichia coli (E. coli) and total bacterial diversity from wastewater effluent. Six experiments were conducted with control quartz sand and sand columns containing BC, Ag-BC, ZVI, BC with ZVI, or Ag-BC with ZVI. After filtration, Ag-BC, ZVI, BC with ZVI and Ag-BC with ZVI demonstrated more than 90% (> 1 log) removal of E. coli from wastewater samples, while BC, Ag-BC, BC with ZVI and Ag-BC with ZVI also demonstrated efficient removal of tested CECs. Lower bacterial diversity was also observed after filtration; however, differences were marginally significant. In addition, significantly (p < 0.05) higher bacterial diversity was observed in wastewater samples collected during warmer versus colder months. Leaching of silver ions occurred from Ag-BC columns; however, this was prevented through the addition of ZVI. In conclusion, our data suggest that the BC with ZVI and Ag-BC with ZVI sand filters, which demonstrated more than 99% removal of both CECs and E. coli without silver ion release, may be effective, low-cost options for decentralized treatment of reused wastewater. Graphical Abstract available at: https://doi.org/10.1007/s42773-023-00240-y Highlights - The efficacy of BC, Ag-BC, and ZVI sand filtration, and their combinations, in removing contaminants from reused water was evaluated. - Ag-BC, ZVI, BC with ZVI and Ag-BC with ZVI demonstrated > 90% removal of E. coli. - BC, Ag-BC, BC with ZVI and Ag-BC with ZVI demonstrated efficient removal of selected contaminants of emerging concern.
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    Zero-Valent Iron and Sand Filtration Reduces Levels of Cyclospora cayetanensis Surrogates, Eimeria tenella and Eimeria acervulina, in Water
    (Microorganisms, 2024-11-16) Gutierrez, Alan; Tucker, Matthew S.; Yeager, Christina; Fournet, Valsin; Jenkins, Mark C.; Dubey, Jitender P.; Kniel, Kalmia E.; Rosenthal, Benjamin M.; Sharma, Manan
    Recurring outbreaks of cyclosporiasis linked to fresh produce demonstrate the need to develop interventions to reduce C. cayetanensis in irrigation water. C. cayetanensis is resistant to commonly used irrigation water treatments, such as chemical sanitizers, making removal of oocysts by filtration the most suitable intervention. This study evaluated the reduction of Eimeria tenella and E. acervulina, as surrogates for C. cayetanensis, in water using filters packed with sand alone or mixtures of sand and zero-valent iron (ZVI). Water inoculated with Eimeria spp. oocysts was filtered through laboratory-scale (PVC column) and field-scale (swimming pool filter) filters packed with either 100% sand or 50% ZVI/50% sand (v/v). Filtered and backflush water was examined microscopically for oocysts. Laboratory-scale filters with 50% ZVI significantly (p < 0.05) reduced 99.9% of E. tenella oocysts compared to 55.3% with filters containing 100% sand. At the field-scale level, 50% ZVI filters significantly (p < 0.05) reduced 70.5% of E. acervulina oocysts compared to 54.5% by 100% sand filters. Filters were backflushed to examine the recovery of these parasites during routine filter-media cleaning procedures. Backflush recovery of oocysts ranged from 4.42–16.7%. The addition of ZVI significantly improved the reduction of Eimeria spp. oocysts at both filter scales. and should be further investigated as a potential irrigation water intervention to reduce C. cayetanensis.