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Investigation of pathogens removal from wastewater using a hydroponic system

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dc.contributor.author Ndulini, Sinqobile Fanele
dc.date.accessioned 2018-08-06T14:02:42Z
dc.date.available 2018-08-06T14:02:42Z
dc.date.issued 2017
dc.identifier.uri http://hdl.handle.net/10530/1697
dc.description A dissertation submitted to the Faculty of Science and Agriculture in fulfillment of the requirements for the Degree of Master Of Science (Microbiology) in the Department of Biochemistry and Microbiology at the University Of Zululand, 2017 en_US
dc.description.abstract Microbial contamination in water sources is a threat to public health and environment. It may lead to distribution of pathogenic microorganisms in water, which may lead to waterborne diseases outbreaks. The current municipal wastewater treatment systems employ the chlorination process for disinfection and inactivation of pathogenic microorganisms. This process has been associated with life threatening drawbacks, which has necessitated the application of green technology in wastewater treatment sector. This work was aiming at investigating the reduction of pathogens in the hydroponic system. A vertical flow constructed wetland planted with emergent macrophytes (Bidens pilosa L and Amaranthus hybridus L) was used to treat wastewater treatment from the secondary stage of the conventional sewage treatment process. Wastewater samples were collected at different hydraulic retention times and analyzed for physiochemical parameters (temperature, pH and dissolved oxygen), organic material and pathogens concentrations. A field multimeter probe was used for measuring physiochemical parameters. The respective cell tests and Aqualytic Thermostatic Cabinet was used to measure organic material content. The real-time qPCR was used for the quantification of pathogens. The removal efficiency of pathogens in the system after treatment was 59%, 73% and 18% for E. coli, Salmonella spp. and Shigella spp. respectively. The removal was not statistically significant (p=0.06), which indicated that the system was able to efficiently remove pathogens from wastewater. The physiochemical parameters were correlated with the reduction of pathogens. The temperature had a positive correlation with pathogens removal (0.15≤r≤.083). While pH had a negative correlation with pathogens removal (-0.90≤r≤0.09). Dissolved oxygen also had a negative correlation with pathogens removal (-0.99≤r≤-0.65), and COD had a positive correlation with pathogens removal (0.19≤r≤0.99). These correlations indicated that there was some influences of physiochemical parameters on the pathogens reduction in the system. Pathogens removal mechanism in the system was also investigated through investigation of antimicrobial production by macrophytes. The plant extract was prepared and screened for phytochemical compounds, which revealed the presence of saponins, alkaloids, tannins and terpenoids. Salmonella, Shigella and E. coli were selected as the pathogens of public concerns and tested against the plant extracts of macrophytes using the method described by Eloff 1998. Where the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the methanol extracts were determined. The MIC of B. pilosa L extract against pathogens ranged between 25-50 mg/ml while A. hybridus L had the MIC at 25 mg/ml only. The MBC results showed that the extracts inhibition activity was not lethal but bacteriostatic to the pathogens of interest. This has shown that macrophytes are capable of inactivating and ultimately reducing pathogens in the system. Thus the study found that the hydroponics have a potential of being used to remove pathogens in wastewater treatment. This technology could be used in a demanding area of the water sector if properly constructed and optimized. en_US
dc.description.sponsorship National Research Foundation Of South Africa Council for Scientific and Industrial Research (CSIR) en_US
dc.publisher University of Zululand en_US
dc.subject microbial contamination --pathogenic microorganisms waterborne diseases en_US
dc.title Investigation of pathogens removal from wastewater using a hydroponic system en_US
dc.type Thesis en_US

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