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Solar disinfection of wastewater to reduce contamination of lettuce crops by Escherichia coli in reclaimed water irrigation

Bichai, Françoise, Polo-López, M. Inmaculada and Fernandez Ibanez, P (2012) Solar disinfection of wastewater to reduce contamination of lettuce crops by Escherichia coli in reclaimed water irrigation. Water Research, 46 (18). pp. 6040-6050. [Journal article]

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URL: http://dx.doi.org/10.1016/j.watres.2012.08.024

DOI: 10.1016/j.watres.2012.08.024


Low-cost disinfection methods to allow safe use of recycled wastewater for irrigation can have important beneficial implications in the developing world. This study aims to assess the efficiency of solar disinfection to reduce microbial contamination of lettuce crops when solar-treated wastewater effluents are used for irrigation. The irrigation study was designed as a complete experimental loop, including (i) the production of irrigation water through solar disinfection of real municipal wastewater treatment plant effluents (WWTPE), (ii) the watering of cultivated lettuce crops at the end of solar treatment, and (iii) the detection of microbial contamination on the irrigated crops 24 h after irrigation. Solar disinfection was performed using two types of reactors: (i) 20-L batch borosilicate glass reactors equipped with CPC to optimize solar irradiation, and (ii) 1.5-L PET bottles, i.e. the traditional SODIS recipients commonly used for disinfection of drinking water in devel- oping communities. Both solar and H2O2-aided solar disinfection processes were tested during 5 h exposure of WWTPE, and Escherichia coli inactivation was analysed. A presence/ absence detection method was developed to analyse lettuce leaves sampled 24 h after watering for the detection of E. coli. Results of inactivation assays show that solar disin- fection processes can bring down bacterial concentrations of >103e104 E. coli CFU mL 1 in real WWTPE to <2 CFU/mL (detection limit). The absence of E. coli on most lettuce samples after irrigation with solar-disinfected effluents (26 negative samples/28) confirmed an improved safety of irrigation practices due to solar treatment, while crops irrigated with raw WWTPE showed contamination.

Item Type:Journal article
Keywords:Escherichia coli Hydrogen peroxide Irrigation Lettuce Solar disinfection Wastewater reuse
Faculties and Schools:Faculty of Computing & Engineering
Faculty of Computing & Engineering > School of Engineering
Research Institutes and Groups:Engineering Research Institute
Engineering Research Institute > Nanotechnology & Integrated BioEngineering Centre (NIBEC)
ID Code:37011
Deposited By: Dr Pilar Fernandez-Ibanez
Deposited On:09 Mar 2017 09:57
Last Modified:17 Oct 2017 16:27

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