>Magister Scientiae - MSc / To address the urgent need for safe potable water in South Africa’s rural areas, sustainable systems for water disinfection at the village-scale of operation are required.In this thesis, the development of a small-scale water chlorination system that runs on salt and solar panels is described. The system combines a membrane-based hypochlorite generator, or “membrane electrolyser”, with an automated hypochlorite dosing system.The system was designed to (i) coordinate hypochlorite production and dosing automatically in a flow-through system, and (ii) fit inline with low pressure pipelines from overhead storage tanks or raised water sources. Low cost materials were used for construction, and water-powered mechanisms were devised to control both brine supply to the electrolyser and regulation of water flow. The capacity of the system was based on the maximum daily output of the electrolyser at ~20 g of sodium hypochlorite. This was sufficient chlorinate up to 10 kL of water per day using less than 80 g of salt and less than 0.1 kW.h of electricity. The cost of the system was estimated at ~R10 000 and therefore potentially affordable for communities up to 100 people, e.g. small farms and villages.Testing of the system was carried out at a farm site in Worcester (Western Cape) using remote monitoring of current levels in the electrolyser. Operation of the system over a two month test period, dosing at ~4 mg/L, produced consistent chlorination measured as(FAC). Community participation in maintenance of the brine supply was managed and chlorinated water was made available to the community after a brief social survey was conducted. Community awareness of chlorination was minimal. No significant history of diarrhoea was reported. However, the community regularly boiled their tap water in response to turbidity increase in summer.The system was affected by turbidity increase in the local water, which caused a drop in electrolyser current and chlorine production due to particle blockage of the membrane in the electrolyser. However, turbidity at acceptable levels for chlorination was found to have no detrimental effect on the system’s performance. The system showed promise for rural implementation providing low turbidity was maintained. Therefore,groundwater sites, and surface waters with appropriate clarification systems are recommended for the system’s installation. Further testing of the system will be required to establish its long term viability in the hands of a rural community.

Surgical site infection is a major postoperative complication that causes patient suffering and is costly for society. The general aim of this thesis was to test and describe interventions performed by operating room (OR) nurses to prevent bacterial growth in surgical patients, with the intent to prevent surgical site infections (SSIs) whilst increase patients comfort. In studies I and II, 220 pacemaker patients were tested to compare pre-heated skin disinfection with room-temperature skin disinfection regard-ing bacterial growth, skin temperature and patient experience. Preheated skin disinfection was not less effective compared to room-temperature skin disinfection in reducing bacterial growth after skin disinfection and there were no differences regarding SSIs three month postoperatively. Preheated skin disinfection reduces skin heat loss and was perceived as more pleas-ant compared to room-temperature skin disinfection. In study III, 12 OR nurses were examined regarding bacterial growth on their hands and at the sterile glove cuff end after surgical hand disinfec-tion and again after wearing sterile surgical gloves during surgery. They were compared with a control group of 13 non-health care workers. OR nurses’ hands had higher amounts of bacterial growth at two of three culture sites after surgical hand disinfection compared with the control group, and the bacterial growth increased in both groups with time during surgery. There seems to be a risk of bacterial growth at the glove cuff end during surgery, involving the same type of bacteria as isolated from the hands. In study IV, 890 OR nurses answered an online questionnaire describ-ing OR nurses interventions guided by national guidelines to reduce SSIs, such as preparation of the patient skin, patient temperature, and OR ma-terials used. The proportion of the OR nurses who complied with the national guidelines preventive interventions was high: skin disinfection solution (93.5%), drapes (97.4%) and gowns (83.8%), and double gloves (73%). However, when guidelines were lacking the interventions differed.

O cuidado a saúde incorpora continuamente, novas tecnologias relacionadas a produtos e processos que podem trazer riscos, especialmente, quando não possuem embasamento técnico-científico. Ampolas de plástico são amplamente utilizadas no preparo de injetáveis, no entanto, a contaminação biológica das soluções na sua abertura é ainda questionável. Sabe-se que o risco de infecção tem etiologia multifacetada envolvendo aspectos complexos da microbiota endógena e das condições ambientais. O objetivo do estudo é contribuir para com a segurança microbiológica da abertura de ampolas com base no procedimento de desinfecção e, assim, minimizar os riscos de contaminação biológica no preparo de injetáveis. Trata-se de um experimento de laboratório que permitiu avaliar a esterilidade do conteúdo das ampolas e, consequentemente produziu evidencias acerca da segurança microbiológica no preparo de injetáveis. Para determinação se a abertura de ampolas possibilita veiculação bacteriana para as soluções utilizaram-se dois métodos de desinfecção do gargalo um com suabe e outro com algodão ambos umedecidos em álcool a 70%. Das 120 ampolas de plástico com água esterilizada 60 tiveram seus gargalos contaminados intencionalmente com Serratia marcescens (ATTCC 14756) e outra metade com Staphylococcus aureus resistente à meticilina (MRSA) (ATTCC 43300) na ordem de 106 UFC/mL. Na abertura das respectivas ampolas utilizaram-se os princípios e o rigor de assepsia em termos de higiene das mãos e uso de luvas esterilizadas. Na avaliação da positividade das culturas uma alíquota da solução de cada ampola foi pipetada em caldo nutriente e incubada a 35ºC por 14 dias. A fricção dos gargalos das ampolas com suabe ou bolas de algodão embebidas em 3 ml de álcool a 70% não foi eficaz na redução da contaminação do conteúdo destas ampolas. Evidencia-se que houve maior contaminação nas ampolas, intencionalmente contamindas com Serratia marcescens, que receberam desinfecção com suabe 19 (63,3%) comparado as ampolas 15 (50%) que foram desinfetadas com bolas de algodão embebidas em álcool. As ampolas contaminadas com Staphylococcus aureus resistente à meticilina independentemente de utilizar suabe ou bolas de algodão embebidas em álcool, a contaminação do conteúdo das ampolas foi alta 24 (80%) e 18 (60%), respectivamente. Das 60 (100%) ampolas contaminadas com Serratia marcescens 34 (56,7%) apresentaram contaminação da água destilada e, das 60 (100%) ampolas contaminadas com Staphylococcus aureus resistente à meticilina, 42 (70%) apresentaram contaminação. A elucidação do processo de contaminação do conteúdo de ampolas de plástico durante sua abertura é urgente, especialmente considerando a possibilidade do contato da solução com o meio externo e vice- versa. Consta-se que a temática carece de mais investimentos de pesquisa dado a relevância do procedimento de desinfecção na redução da carga microbiana. / The health care incorporates continuously new technologies related to products and administration processes that may pose risks, especially when there is no technical- scientific basis. Plastic ampoules are widely used in the preparation of injectables, however, biological contamination in solutions at its opening is still questionable. It is known that the risk of infection presents a multifaceted etiology involving complex aspects of endogenous microbiota and environmental conditions. The present investigation was carried out in order to contribute to the microbiological safety of opening ampoules based on disinfection procedure and thereby minimize the risk of biological contamination in the preparation of injectables. This is a laboratory experiment that allowed to evaluate the sterility of ampoules´ contents and consequently produced evidences regarding the microbiological safety in the preparation of injectables. To determine whether the opening of ampoules allows the carrying of bacteria into the solutions it was used two methods of ampoule neck disinfection, one with cotton balls and another with cotton swab both soaked with 70% alcohol. Of the 120 plastic ampoules containing sterile water, 60 had the ampoules necks intentionally contaminated with Serratia marcescens (ATTCC 14756) and the other half with methicillin-resistant Staphylococcus aureus (MRSA) (ATTCC 43300) of the order of 106 CFU/mL. At the opening of respective ampoules it was used the principles of strict asepsis and rigor in terms of hand hygiene and use of sterile gloves. In the evaluation of positive cultures an aliquot of solution from each ampoule was pipetted in nutrient broth and incubated at 35 °C for 14 days. Rub the ampoules necks with swab or cotton balls soaked with 70% alcohol in 3 ml was not effective in decreasing contamination of contents of those ampoules. It is evident that there were more contamination in ampoules intentionally contaminated with Serratia marcescens which received disinfection with swabs 19 (63.3%) if compared ampoules disinfected with cotton balls soaked in alcohol 15 (50%). Ampoules contaminated with methicillin-resistant Staphylococcus aureus neither swab nor cotton balls soaked in alcohol was effective, contamination of the contents of the ampoules 24 was high (80%) and 18 (60%), respectively. Of the 60 (100%) ampoules contaminated with Serratia marcescens 34 (56.7%) had distilled water contaminated, and from 60 (100%) ampoules contaminated with methicillin-resistant Staphylococcus aureus, 42 (70%) were contaminated. The elucidation of contamination process of contents of plastic ampoules during its opening is an urgent need, especially considering the possibility of contact of the solution with the external environment and vice versa. The evidence suggests that the issue needs more research investments given the relevance of the disinfection procedure in decreasing microbial load.

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To mitigate microbial activity in swimming pools and to assure hygienic safety for bathers, pool systems have a re-circulating water system ensuring continuous water treatment and disinfection by chlorination. A major drawback associated with the use of chlorine as disinfectant is its potential to react with organic matter (OM) present in pool water to form potentially harmful disinfection by-products (DBP). In this thesis, the treatment performance of different combinations of conventional and novel treatment processes was compared using a pilot scale swimming pool model that was operated under reproducible and fully controlled conditions. The quality of the pool water was determined in means of volatile DBPs and the concentration and composition of dissolved organic carbon (DOC). Further, overall apparent reaction rates for the removal of monochloramine (MCA), a DBP found in pool water, in granular activated carbon (GAC) beds were determined using a fixed-bed reactor system operated under conditions typical for swimming pool water treatment. The reaction rates as well as the type of reaction products formed were correlated with physico-chemical properties of the tested GACs.

The disinfection of wastewater is not something that is currently in use at any wastewater treatmentplant in Sweden. The government has however stated some requirements for some wastewatertreatment plants to have a plan to implement disinfection in their treatment process, if asked.Therefore the goal of the project is to research if disinfection with sodium hypochlorite can beimplemented at Slottshagen wastewater treatment plant. There are several factors that will affect the efficacy of the disinfection of the wastewater. Firstly, thedisinfection process is dependent on the pH of the water solution. This is because the weakhypochlorous acid has better disinfection than the hypochlorite ion, and hypochlorous acid is presentthe most in the solution at pH 3-6. Another factor that is important to consider is the amounts ofnutrients present in the solution, since the chlorine oxidizes the nutrients rather than reacting with theorganisms in the solution. Some of the products from the oxidation of the nutrients are bad for bothhuman health and the environment. Also the temperature of the water and the concentration of thechlorine will affect the disinfection. Lastly, depending on which organism that is sought out to bedisinfected, the chlorine will have more or less effect on that particular organism. To research the chlorination effect, different additions of sodium hypochlorite were added to samplesolutions from the treatment plant and got to react in the solution for 5 minutes. Following thesamples were neutralized with ascorbic acid, and the amount of E. coli , coliform bacteria andintestinal enterococci were analyzed. The disinfection of the water during 1,5 minutes and at a shortertemperature were also analyzed. The results showed that the temperature, the contact time with thesolution and the concentration all are important factors to reach a proper disinfection, but the resultsalso showed that the amount of bacteria in the solution also is an aspect to take into considerationwhen treating wastewater. Finally, the considerations of disinfection of the wastewater with sodium hypochlorite is discussed.The point of addition of the chlorine was concluded to best be directly after the last chemicaltreatment step. When analysing if the disinfection would be possible, the disinfection was from theresults possible, but it was noticed that the results fluctuated a lot. The most probable reason why isbecause of the water quality. The water quality in general fluctuates regularly throughout the day, aswell as in between days of the week. Therefore throughout the disinfection process, the additions ofchlorine would need to be depending on several parameters, making the disinfection difficult toimplement. One solution to this could be to add a lot of chlorine to the bulk water at all times, but itwould cost too much if treating the water for a longer time, as well as it would be a higher risk to theenvironment. A solution to this problem could be to possibly neutralize the water before it is releasedas well, however when analyzing the cost of the ascorbic acid that was used as neutralization in thisproject, the cost to neutralize the water completely would be too high. Lastly it was discussed that theonly time disinfection of the wastewater would give any desirable results, is if the specific organismsthat are being sought out to be treated are bacteria or some viruses. If the particular organism that iswished to be treated is parasites, the disinfection with chlorine would not work.

As climate change progresses, the number of extreme weather events are predicted to rise and generate an increase in climate related humanitarian emergencies. These emergencies result in complex displacements of populations, unsanitary conditions, and a corresponding increase in diarrheal disease risks within affected communities. Because diarrheal disease ranks as one of the major contributors to overall morbidity and mortality rates following a disaster, it is critically important that aid agencies are prepared to make informed decisions regarding the prevention of disease transmission. As water is one of the main transmission routes of diarrheal disease, providing clean and safe drinking water is acknowledged as one of the most important and effective interventions. Once we acknowledge the importance of this resource, we also acknowledge the need for quick, simple, and effective water treatment solutions. The term point-of-use (POU) water treatment defines water treatment systems and technologies that are used at the point of consumption. These systems often treat relatively small batches of water and are operated by the consumer or head of household. POU water treatment systems and safe storage techniques have been shown to improve water quality and decrease diarrheal disease incidence and are therefore an effective option in humanitarian emergencies. One type of POU water treatment product - coagulant/disinfection products (CDPs) which are also known as flocculant/disinfectants, have been increasingly used in response to humanitarian emergencies. CDPs are shown to provide microbial and aesthetic (i.e. turbidity reductions) water quality improvements and post-treatment protective free chlorine residuals (FCRs). The relative simplicity of CDPs allows quick intervention for communities with few resources plus CDPs are durable, small, and ready for quick deployment. However, limited research has been completed on the different CDPs on the market or on methods to improve them. This thesis explores CDPs and their role in emergency response through two interlinked perspectives: 1. First, in an overall review compiled as Manuscript #1 (Chapter 2), I assess the existing and current CDPs, how they perform in comparison to global water treatment guidelines, and where their limitations lie. The outcomes of this study provide a simple analysis for aid agencies to carefully select the CDPs used in emergency interventions; and 2. I take the findings from the research completed in Chapter 2 to develop a computational modelling approach to improving the residual protective capacity of the CDPs. These results are presented in Manuscript #2 (Chapter 3) . The outcomes are intended to serve two purposes: (1) to provide a baseline computational model to guide and encourage improvement and testing of these products by manufacturers; and (2) to provide an educational tool to facilitate understanding of these products and the key functions taking place during their treatment. This thesis addressed the research objective of invoking conversation surrounding effective emergency response through developing solutions to provide clean drinking water in at-risk communities during complex humanitarian emergencies. / Graduate

M. Tech (Department of Biotechnology, Faculty of Applied and Computer Sciences) Vaal University of Technology. / The presence of enteric viruses in drinking water poses a health risk to consumers. It is therefore very important for drinking water suppliers to provide water that is pathogen free and fit for human consumption. This can be achieved by an effective water treatment system that ensures the safety of water from the treatment plant until the water reaches the consumer. This study assessed the ability of a conventional water treatment system to remove viruses. The system consisted of three unit processes, namely, clarification, sand filtration and disinfection. These processes were simulated on a bench-scale to determine the effectiveness of each one at removing viruses. Clarification was conducted using a Phipps and Bird jar testing system and three different chemical treatments: (i) Polyelectrolyte (SUDFLOC 3835), (ii) a combination of lime and activated silica and (iii) a combination of lime, activated silica and ferric chloride. Sand filtration was simulated using a Phipps and Bird column filtration system. Disinfection was conducted using free chlorine. The findings from this study showed that the removal or inactivation of viruses increased with an increase in the concentration of chemicals added. For clarification, the combination of lime, activated silica and ferric chloride was the most effective treatment for the removal or inactivation of viruses. Sand filtration was found to be ineffective for the removal of viruses. Disinfection was shown to be the most effective process for the removal or inactivation of viruses. While clarification, sand filtration and disinfection did not remove or inactivate viruses equally, the entire treatment chain is still essential. This is because even if a barrier does not directly remove viruses it ensures that subsequent processes can function effectively. Overall the treatment processes should not be considered as discrete barriers but rather an integrated system that must function throughout to avoid a risk to customers.

Introduction: Community mitigation strategies (CMS) have demonstrated to be effective in the reduction of transmission and incidence of COVID-19, especially in the population with symptoms associated with the disease. The aim of this study was to evaluate the association between the presence of COVID-19 symptoms and adherence to CMS in Latin American adults. Methods: We carried out a secondary analysis of a database developed by the University of Maryland and Facebook social network during the COVID-19 pandemic. We included Latin American adults that used the Facebook platform and participated in a survey conducted from April 23 to May 23, 2020. The principal outcome variable was reported compliance with the three main CMS (physical distancing, use of face masks, and hand washing). The exposure variable included symptoms suspicious for COVID-19 defined as the presence of three or more symptoms of an acute clinical case of COVID-19. We performed generalized linear models of the Poisson family with a logarithmic link function to evaluate the association between the presence of COVID-19 symptoms and reported compliance with CMS. We calculated crude and adjusted prevalence ratios (PR) with their 95% confidence intervals (95%CI). Results: We analyzed 1,310,690 adults from Latin America; 48.1% were male and 42.9% were under 35 years of age. The prevalence of suspicious symptoms of COVID-19 was 18.5% and reported compliance with the three CMS was 45.3%. The countries with the highest proportion of reported compliance with the three CMS were Peru, Bolivia and Panama, while those with the lowest reported compliance were Costa Rica, Nicaragua and Honduras. In the adjusted model, people with suspicious symptoms for COVID-19 had a 14% lower compliance with the three CMS (aPR = 0.86; 95%CI: 0.85–0.87; p < 0.001). Conclusions: Less than half of the participants complied with the CMS, and those presenting suspicious symptoms for COVID-19 had lower reported compliance with the three CMS. / University of Maryland / Revisión por pares

No description available.