Presentation Title

Analysis of the pathogen mobility from wastewater to suspended duckweed

Faculty Mentor

Natalie Mladenov, Monica Palomo

Start Date

18-11-2017 12:30 PM

End Date

18-11-2017 1:30 PM

Location

BSC-Ursa Minor 115

Session

Poster 2

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Global efforts are being made to ensure safe water sources, sanitation, food security, and sustainable agriculture through the United Nations Sustainable Development Goals. These efforts have attracted interest in the use of duckweed, a small angiosperm that thrives in nutrient rich waters across the globe, for polishing treatment of effluent from anaerobic baffled reactor (ABR) systems, and as a green-fertilizer or soil amendment. However, it is hypothesized that elevated concentrations of pathogenic bacteria may be present in the biomass of duckweed grown in ABR effluent. In order to address this, lab-scale batch and continuous-flow duckweed ponds were constructed with a 3 and 2-day hydraulic residence time (HRT), respectively to determine pathogen concentrations in Lemna minor and a mixed duckweed with both Lemna minor and Wolffia arrhiza. Analysis for Total Coliforms (TC) and E. coli indicator bacteria in ABR effluent and duckweed biomass was conducted using a spread plate method with 3M Petrifilms and Brilliance E. coli/coliform selective agar. Counts of E. coli and TC were lower in the effluent of ponds with duckweed than in controls without. After growth in ABR effluent, Lemna minor and mixed biomass contained E. coli and TC at concentrations of 10and 8 log CFU/g, respectively. When Lemna minor and mixed duckweed was dried at 32°C, E. coli and TC present in duckweed biomass were reduced to a magnitude of 3 log CFU/g within the first 24 hours. During the next 48 hours E. coli and TC increased to 4.19(±0.07) and 4.78(±0.06) log CFU/g, respectively in Lemna minor biomass. In mixed biomass E. coli and TC increased to 4.04(±0.18) and 4.80(±0.11) log CFU/g respectively. These results indicate that pathogen counts in the ABR effluent are reduced and taken up by duckweed biomass, posing a potential health risk when used as a green-fertilizer or soil amendment.

Keywords: Agriculture, Anaerobic Baffled Reactor (ABR), Constructed Wetlands, Decentralized Wastewater Treatment System (DEWATS), Duckweed, E. coli, Pathogens, Sanitation, Sorption, Total Coliforms (TC)

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Nov 18th, 12:30 PM Nov 18th, 1:30 PM

Analysis of the pathogen mobility from wastewater to suspended duckweed

BSC-Ursa Minor 115

Global efforts are being made to ensure safe water sources, sanitation, food security, and sustainable agriculture through the United Nations Sustainable Development Goals. These efforts have attracted interest in the use of duckweed, a small angiosperm that thrives in nutrient rich waters across the globe, for polishing treatment of effluent from anaerobic baffled reactor (ABR) systems, and as a green-fertilizer or soil amendment. However, it is hypothesized that elevated concentrations of pathogenic bacteria may be present in the biomass of duckweed grown in ABR effluent. In order to address this, lab-scale batch and continuous-flow duckweed ponds were constructed with a 3 and 2-day hydraulic residence time (HRT), respectively to determine pathogen concentrations in Lemna minor and a mixed duckweed with both Lemna minor and Wolffia arrhiza. Analysis for Total Coliforms (TC) and E. coli indicator bacteria in ABR effluent and duckweed biomass was conducted using a spread plate method with 3M Petrifilms and Brilliance E. coli/coliform selective agar. Counts of E. coli and TC were lower in the effluent of ponds with duckweed than in controls without. After growth in ABR effluent, Lemna minor and mixed biomass contained E. coli and TC at concentrations of 10and 8 log CFU/g, respectively. When Lemna minor and mixed duckweed was dried at 32°C, E. coli and TC present in duckweed biomass were reduced to a magnitude of 3 log CFU/g within the first 24 hours. During the next 48 hours E. coli and TC increased to 4.19(±0.07) and 4.78(±0.06) log CFU/g, respectively in Lemna minor biomass. In mixed biomass E. coli and TC increased to 4.04(±0.18) and 4.80(±0.11) log CFU/g respectively. These results indicate that pathogen counts in the ABR effluent are reduced and taken up by duckweed biomass, posing a potential health risk when used as a green-fertilizer or soil amendment.

Keywords: Agriculture, Anaerobic Baffled Reactor (ABR), Constructed Wetlands, Decentralized Wastewater Treatment System (DEWATS), Duckweed, E. coli, Pathogens, Sanitation, Sorption, Total Coliforms (TC)