Investigating the feasibility of a chlorinated resin for water disinfection in rural and peri-urban areas

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dc.contributor.advisorPillay, Visvanathan Lingamvrthien_ZA
dc.contributor.authorMtimuni, Tadalaen_ZA
dc.contributor.otherStellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering. Process Engineering.en_ZA
dc.date.accessioned2024-03-05T09:57:27Zen_ZA
dc.date.accessioned2024-04-26T22:38:25Zen_ZA
dc.date.available2024-03-05T09:57:27Zen_ZA
dc.date.available2024-04-26T22:38:25Zen_ZA
dc.date.issued2024-03en_ZA
dc.descriptionThesis (MEng)--Stellenbosch University, 2024.en_ZA
dc.description.abstractENGLISH ABSTRACT: Water is essential for humanity in daily household activities, but most water sources are contaminated and necessitate treating water before it can be used. Chlorine has been the predominant disinfectant in rural areas, but determining the right dosage has been challenging. Chlorinated resins are a promising option as they release chlorine in a controlled manner. However, control of chlorination during the synthesis of these resins is a major problem. Previous chlorine sources released reactive chlorine (Cl) species during chlorination, resulting in unreacted chlorine that did not bind on the specific site and over-chlorinated resins. Hence, this study aimed to synthesize a resin using sodium dichloroisocyanurate (NaDCC) as a chlorine source that releases less reactive Cl species and could improve the chlorination process. First, a chlorinated resin was developed using a two-step procedure. The first procedure was split into two: a hydantoin with amide functional groups was prepared and grafted onto the resin's surface. The modified resin was then chlorinated using NaDCC. The first procedure used a two-factor central composite design (CCD) to optimize temperature and reaction time. A three-factor central composite design was used in the chlorination reaction by varying temperature (20-30 °C), reaction time (40-50 mins), and pH (5.5-6.5). The optimum conditions were identified as a temperature of 25°C, a reaction time of 54 minutes, and a pH of 5. The developed resin contained 6.18% chlorine (by mass%), in contrast to the earlier chlorinated resins that had chlorine loadings of more than 20% (mass%). The performance of the developed resin was evaluated through chlorine release experiments and disinfection efficacy experiments using a 1-litre water sample with a bacterial concentration of 3.6 x106 cfu/ml. The first-order kinetic model was used to study the chlorine release behaviour of the resin. A resin mass of 485.43 mg (containing 30 mg of Cl) exhibited a chlorine release rate of 0.351 mg/minute. Experiments on disinfection efficacy demonstrated that a resin mass with over 30 mg of chlorine achieved a 99.99% reduction in bacteria concentration within 5 minutes. A lab-scale point-of-use (POU) water treatment system with a resin disinfecting column was designed using the parameters obtained from the first-order kinetic model for chlorine release. A resin column with a 3 cm diameter achieved a minimum flow rate of 0.89 L/min and demonstrated a disinfection efficacy of 99.99%. The resin was stable; it maintained a 99.99% disinfection efficacy and a residual chlorine concentration of 0.3 mg/L after flushing 1L of water through the resin column for 20 continuous cycles. By a small margin, the chlorine content in the resin decreased with increasing disinfection cycle A feasibility study was conducted to evaluate the disinfection efficacy, ease of implementation, and environmental impact of the resin POU system in comparison to the World Health Organization (WHO) standards for water treatment technologies. The chlorinated resin achieved 99.99% (4 log10) bacterial elimination, aligning with the WHO standards. The scalability advantages of the POU system were demonstrated, allowing easy implementation. In addition, the resin-based disinfection unit maintained a residual chlorine level of 0.3 mg/L, meeting the WHO standards on residual chlorine. With the improved chlorine loading, the chlorinated resin holds a promising prospect as a potential point of use water treatment device for peri-urban and rural areas. However, a techno-economic analysis will be necessary.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.af_ZA
dc.description.versionMastersen_ZA
dc.format.extentxv, 161 pages : illustrationsen_ZA
dc.identifier.urihttps://scholar.sun.ac.za/handle/10019.1/130576en_ZA
dc.language.isoen_ZAen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subjectHousehold water disinfection; N-halamine polymers; Merrifield resin; Sodium dichloroisocyanurate; Electrophilic substitution reaction; First-order kinetic drug release modelen_ZA
dc.subject.lcshWater -- Purification -- Chlorinationen_ZA
dc.subject.lcshGums and resinsen_ZA
dc.subject.lcshSodium dichloroisocyanurateen_ZA
dc.subject.lcshChemical kineticsen_ZA
dc.subject.lcshTechno-economic analysisen_ZA
dc.titleInvestigating the feasibility of a chlorinated resin for water disinfection in rural and peri-urban areasen_ZA
dc.typeThesisen_ZA
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