Research Publications (Academic Support)

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A cluster-randomized controlled trial to reduce Diarrheal disease and dengue entomological risk factors in rural primary schools in Colombia
(National Centre for Biotechnology Information, 2016-11-07) Overgaard, Hans J.; Alexander, Neal; Matiz, María Inés; Jaramillo, Juan Felipe; Olano, Victor Alberto; Vargas, Sandra Lucía; Sarmiento, Diana; Lenhart, Audrey; Stenström, Thor-Axel
Background As many neglected tropical diseases are co-endemic and have common risk factors, inte-grated control can efficiently reduce disease burden and relieve resource-strained public health budgets. Diarrheal diseases and dengue fever are major global health problems sharing common risk factors in water storage containers. Where provision of clean water is inadequate, water storage is crucial. Fecal contamination of stored water is a common source of diarrheal illness, but stored water also provides breeding sites for dengue vector mosquitoes. Integrating improved water management and educational strategies for both diseases in the school environment can potentially improve the health situation for students and the larger community. The objective of this trial was to investigate whether interven-tions targeting diarrhea and dengue risk factors would significantly reduce absence due to diarrheal disease and dengue entomological risk factors in schools. Methodology/Principal Findings A factorial cluster randomized controlled trial was carried out in 34 rural primary schools (1,301 pupils) in La Mesa and Anapoima municipalities, Cundinamarca, Colombia. Schools were randomized to one of four study arms: diarrhea interventions (DIA), dengue interven-tions (DEN), combined diarrhea and dengue interventions (DIADEN), and control (CON). Interventions had no apparent effect on pupil school absence due to diarrheal disease (p = 0.45) or on adult female Aedes aegypti density (p = 0.32) (primary outcomes). However, the dengue interventions reduced the Breteau Index on average by 78% (p = 0.029), with Breteau indices of 10.8 and 6.2 in the DEN and DIADEN arms, respectively compared to 37.5 and 46.9 in the DIA and CON arms, respectively. The diarrhea interventions improved water quality as assessed by the amount of Escherichia coli colony forming units (CFU); the ratio of Williams mean E. coli CFU being 0.22, or 78% reduction (p = 0.008). Conclusions/Significance Integrated control of dengue and diarrhea has never been conducted before. This trial pres-ents an example for application of control strategies that may affect both diseases and the first study to apply such an approach in school settings. The interventions were well received and highly appreciated by students and teachers. An apparent absence of effect in primary outcome indicators could be the result of pupils being exposed to risk factors out-side the school area and mosquitoes flying in from nearby uncontrolled breeding sites. Inte-grated interventions targeting these diseases in a school context remain promising because of the reduced mosquito breeding and improved water quality, as well as educa-tional benefits. However, to improve outcomes in future integrated approaches, simulta-neous interventions in communities, in addition to schools, should be considered; using appropriate combinations of site-specific, effective, acceptable, and affordable interventions.
Development of poly (aspartic acid-co-malic acid) composites for calcium carbonate and sulphate scale inhibition
(Taylor and Fancis, 2014) Kumar, N. Mithil; Gupta, Sanjay Kumar; Jagadeesh, Dani; Kanny, Krishnan; Bux, Faizal
Polyaspartic acid (PSI) is suitable for the inhibition of inorganic scale deposition. To enhance its scale inhibition eﬃciency, PSI was modiﬁed by reacting aspartic acid with malic acid (MA) using thermal polycondensation polymerization. This reaction resulted in poly(aspartic acid-co-malic acid) (PSI-co-MA) dual polymer. The structural, chemical and thermal prop-erties of the dual polymers were analysed by using scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diﬀraction, diﬀerential scanning calorimetry and gel permeation chromatography. The eﬀectiveness of six diﬀerent molar ratios of PSI-co-MA dual polymer for calcium carbonate and calcium sulphate scale inhibition at laboratory scale batch experiments was evaluated with synthetic brine solution at selected doses of polymer at 65–70°C by the static scale test method. The performance of PSI-co-MA dual polymer for the inhibition of calcium carbonate and calcium sulphate precipitation was compared with that of a PSI single polymer. The PSI-co-MA exhibited excellent ability to control inor-ganic minerals, with approximately 85.36% calcium carbonate inhibition and 100% calcium sulphate inhibition at a level of 10 mg/L PSI-co-MA, respectively. Therefore, it may be reasonably concluded that PSI-co-MA is a highly eﬀective scale inhibitor for cooling water treatment applications.
Ecological functionality of the Upper and Middle Vaal Water Management areas
(2012-12-05) Dzwairo, Bloodless; Otieno, Fredrick Alfred O.; Ochieng, George M.
A harmonised in-stream water quality guideline was constructed for the Upper and Middle Vaal Water Management Areas (WMAs) using ideal catchment background values for the sub-catchments; Vaal dam, Vaal barrage, Klip River and Blesbokspruit/Suikerbosrant Rivers. Data for years 2003 to 2009 was interpolated to a daily time-step for 2526 days at 21 monitoring sites covering both WMAs. Conductivity was used as a surrogate to capture the variability in water quality. This provided an ecological functionality model of the study area, coded for ranges 10-18, 19-45, 46-80, 80< and 81-100 mS/m. The Upper and Middle Vaal basin is currently extremely vulnerable to changes in water quality, uncertainty about changes which it can tolerate, and the fact that there are very limited options for mitigating effects of poor water quality in the basin, overall. Thus a precautionary approach is being proposed in this paper, in order to protect the ecological functionality of the aquatic ecosystem. The proposed harmonised guideline presents a crucial model to pre-determine the ecological functionality for any water point in the study area, in order to provide upstream-downstream pollution trading and other decision support processes towards sustainable basin management
Exploring the potential reservoirs of non speciﬁc TEM beta lactamase (blaTEM) gene in the Indo-Gangetic region : a risk assessment approach to predict health hazards
(Elsevier, 2016) Singh, Gulshan; Vajpayee, Poornima; Rani, Neetika; Amoah, Isaac Dennis; Stenström, Thor-Axel; Shanker, Rishi
The emergence of antimicrobial resistant bacteria is an important public health and environ-mental contamination issue. Antimicrobials of -lactam group accounts for approximately two thirds, by weight, of all antimicrobials administered to humans due to high clinical efﬁcacy and low toxicity. This study explores -lactam resistance determinant gene (blaTEM) as emerging con-taminant in Indo-Gangetic region using qPCR in molecular beacon format. Quantitative Microbial Risk Assessment (QMRA) approach was adopted to predict risk to human health associated with consumption/exposure of surface water, potable water and street foods contaminated with bac-teria having blaTEM gene. It was observed that surface water and sediments of the river Ganga and Gomti showed high numbers of blaTEM gene copies and varied signiﬁcantly (p < 0.05) among the sampling locations. The potable water collected from drinking water facility and clinical set-tings exhibit signiﬁcant number of blaTEM gene copies (13 ± 0.44–10200 ± 316 gene copies/100 mL).
Integrating quality and cost of surface raw water : upper and middle Vaal water management areas South Africa
(IWA Publishing, 2010) Dzwairo, Bloodless; Otieno, Fredrick Alfred O.
The user-pays principle encourages use of a water tariff structure that incorporates pollution and/or depletion of a water resource because that water represents a capital resource base. Development of a tool that models variability of surface raw water quality in order to predict cost of treatment thus makes economic sense. This paper forms the backbone for an on-going doctoral study in South Africa's Upper and Middle Vaal Water Management Areas (U&MVWMAs) of the Vaal River (VR). Specific objectives of the overall research are; to carry out pollutant tracer hydrochemistry of specific reaches of the U&MVWMAs including producing an integrated ecological functionality for the whole study area, and to develop a tool that models the variability of surface raw water quality using surface raw water tariffs and water quality data for years 2003–2008. This paper concluded that downstream water boards (WBs) paid a higher water resources management charge (WRMC) for more polluted raw water than upstream WBs. It was recommended that a quality-cost model be incorporated at tier1 of the cost chain for water services to ensure fairness of service delivery and spread of burden to consumers.
Making a case for systems thinking approach to integrated water resources management (IWRM)
(Academic Journals, 2010-04-22) Dzwairo, Bloodless; Otieno, Fredrick Alfred O.; Ochieng, George M.
While definite benefits could be gained from integrating the management of natural and human systems, taking into account the effects of human activities on the environment, the task of operationalising and implementing this approach in practice represents an enormous challenge. Some limitations highlighted include the definition of integrated water resources management (IWRM) itself, where it appears to be broad, all-encompassing and impressive but contains ‘‘lofty phrases’’ that have little practical importance for either present or future water management practices. This paper makes recommendations to uptake and incorporate the systems thinking approach (STA) in IWRM decision making processes, an approach envisaged to be more participatory and also process-oriented. Incorporation of socio-economic dynamics is also recommended, with a suggestion that the biophysical relationships like interactions in a basin between water, the human population and settlements should be analysed to the extent possible.
One-dimensional finite difference approach for sedimentation process in sand filled reservoirs
(Academic Journals, 2011-04-04) Olufayo, O. A.; Ochieng, George M.; Ndambuki, Julius M.; Otieno, Fredrick Alfred O.
There have been continuing efforts to decrease silt deposits due to interstitial blockage in sand-filled reservoirs. However, estimating weir height to allow for deposition of required grain sizes is difficult. This paper presents a numerical process-imitating model aimed at improving water storage potential in sand filled reservoirs. The technique uses a finite difference (FD) numerical model to numerically solve mass balance continuity equation built upon the conservative laws of solid-fluid mixture hydrodynamics. Present investigation shows that barrier height used in sand-filled reservoirs determines the grade quality of deposited sands. The predictions of the model compared with laboratory measurements show agreement between computational and experimental results. The study could provide economic and suitability data for increasing water supplies to a small community through determination of appropriate weir height that will increase subsurface water storage potential.
Optimal control intervention strategies using an n-patch waterborne disease model
(Wiley, 2016-11) Collins, Obiora Cornelius; Duffy, Kevin Jan
Waterborne diseases are an important concern in public health, especially in communities with limited access to clean water. Diﬀer-ent community subpopulations can require diﬀerent copping strategies for the same diseases. Modeling is one method to assist understanding and the development of eﬀective strategies. To this end, we investigated the use of meta-population models with three types of control interventions: vaccination, treatment, and water puriﬁcation. Important mathematical features of the model are determined and examined. Optimal control, applied to the model, is also formulated to determine the eﬀective strategies to reduce the spread of the disease. For example, using optimal control, a four-fold reduc-tion in infected individuals is possible. The value of such an improvement to the communities involved would be signiﬁcant.
A process-based model for fluidized bed in sand filled reservoirs
(ASCE: American Society of Civil Engineers, 2011) Olufayo, O. A.; Ochieng, George M.; Ndambuki, Julius M.; Otieno, Fredrick Alfred O.
Arid and semi-arid regions are prone to severe water inadequacies. They are characterized by little rainfall resulting in several seasonal rivers. Seasonal riverbeds provide opportunity for water to be stored in river’s sand-beds while their surfaces may appear dry. It is an important source of water in most rural areas under arid conditions. Several numerical models have been developed for solving sediment problems in alluvial rivers. However, rarely if ever were a model applied for sand filled reservoirs. This study presents a model to understand interacting factors through which physical water storage potential can be increased in sand filled reservoirs. Finite different method (FDM) has been applied to numerically solve mass balance continuity equation in sand filled reservoir. There were reasonable agreements between estimated results and experimental measurements from a laboratory setup. The study could provide economic and suitability data for increasing water supplies to a small community.
Quantification of pathogen inactivation efficacy by free chlorine disinfection of drinking water for QMRA
(IWA Publishing, 2015-09-13) Petterson, S.R.; Stenström, Thor-Axel
To support the implementation of quantitative microbial risk assessment (QMRA) for managing infectious risks associated with drinking water systems, a simple modeling approach for quantifying Log10 reduction across a free chlorine disinfection contactor was developed. The study was undertaken in three stages: firstly, review of the laboratory studies published in the literature; secondly, development of a conceptual approach to apply the laboratory studies to full-scale conditions; and finally implementation of the calculations for a hypothetical case study system. The developed model explicitly accounted for variability in residence time and pathogen specific chlorine sensitivity. Survival functions were constructed for a range of pathogens relying on the upper bound of the reported data transformed to a common metric. The application of the model within a hypothetical case study demonstrated the importance of accounting for variable residence time in QMRA. While the overall Log10 reduction may appear high, small parcels of water with short residence time can compromise the overall performance of the barrier. While theoretically simple, the approach presented is of great value for undertaking an initial assessment of a full-scale disinfection contactor based on limited site-specific information.
Sand water storage : unconventional methods to freshwater augmentation in isolated rural communities of South Africa
(Academic Journals, 2010-10-20) Otieno, Fredrick Alfred O.; Olufayo, O. A.; Ochieng, George M.
South Africa water resources are scarce in global terms with mean annual rainfall of about half world average of 860 mm a year. On the other hand, current economy development with resulting contamination of available water resources will further reduce water availability, if present patterns of water use continue unchanged. The conventional water resources (largely surface water) in the country have been fully exploited with little opportunity for further expansion. So therefore, new approaches are necessary by accessing alluvial aquifers of non-perennial rivers in forming additional water resources in this part of semi-arid region. High evaporative losses from surface storage, increasing costs of large dams and aridity conditions have hindered development of conventional water resources with increasing interest in using groundwater for rural water supply. Many South Africa rivers are non-perennial, therefore, development of unconventional sand water storage is appealing for freshwater augmentation in isolated rural communities. This paper presents overviews of South Africa water resources highlighting sand water storage options for potential application in rural water supply for isolated communities where groundwater potential is low.
Strategies for building resilience to hazards in water, sanitation and hygiene (WASH) systems: The role of public private partnerships
(Elsevier, 2014-07-15) Johannessen, Ase; Rosemarin, Arno; Thomalla, Frank; Gerger Swartling, Åsa; Stenström, Thor-Axel; Vulturius, Gregor
The aim of this paper is to enhance understanding of how the resilience of water, sanitation and hygiene (WASH) systems to hazards can be improved. In turn, this aims to inform different strategies for public and private partnerships (PPPs). In a new approach, to acknowledge the multi levelled nature of resilience; risk at the relevant levels are taken into account, (regional/river basin, urban area, and individual). For these levels, we first describe the different components of risk, vulnerability and resilience of the WASH system that influence people's exposure to hazards. We illustrate these components using examples from case studies in the literature. Using a social learning lens - a crucial ingredient of resilience - we examine opportunities for reducing risks through improving public–private engagement. These are presented as strategies which could guide invest-ment decisions: As pressures from climate change and development add up, businesses must become aware of the risks involved in operating and investing without considering ecosystem health, both in terms of the services they provide for mitigating floods and droughts, as well as in terms of the development approaches that define how ecosystems are managed (e.g. “making space” for, rather than controlling water). There is a need to develop an institutional culture that strives towards greener and more resilient urban environments with the help of various quality assurance methods. Partnerships must reach the poorer customer base, encourage informal small entrepreneurs, and boost financial mechanisms (e.g. micro-insurance, micro-finance) to support the most vulner-able in society.
Towards a more sustainable surface raw water tariff structure in the Vaal basin : a situational analysis
(Academic Journals, 2011-04-18) Dzwairo, Bloodless; Otieno, Fredrick Alfred O.; Ochieng, George M.
With an increasingly urbanised population, further study was necessary to determine if water could be used more efficiently by applying efficient tariff structures in combination with decision support tools in the form of models. This paper highlighted challenges towards establishing a sustainable surface raw water tariff structure. Limitations of using the pollute-pays principle for setting a surface raw water tariff structure within a highly urbanised environment were noted. A tariff structure in the Upper and Middle Vaal Water management Areas which are part of the Vaal basin in South Africa was shown to promote inequity such that a downstream user paid more for using more polluted water. Recommendations specific to the Vaal basin included adopting a user-pays principle and also use of a model that incorporated variability in surface raw water quality for tariff setting and also for purposes of predicting potable water treatment costs.
Uncertainty sources in climate change impact modelling of water resource systems
(UniversityPublications.net, 2014) Oyebode, Oluwaseun Kunle; Adeyemo, Josiah; Otieno, Fredrick Alfred O.
Modelling climate change impacts on water resources have been widely acknowledged to have various complexities. These complexities are due to the complex, dynamic and non-linear characteristics of the changes in atmospheric, climatological and hydrological processes. These changes are majorly as a result of human activities. Assessment of the potential impacts of these changes with the goal of planning adaptation strategies has given birth to numerous methodologies and approaches. However, uncertainty still occurs at almost every phase of the modelling process; from the development and downscaling of emission scenarios to the use of hydrological models. This paper reviews some of the current methods employed in hydrological modelling of climate change impacts and identifies the key sources of uncertainty inherent at each stage of the hydrological modelling process. Strategies that would incorporate of all sources of uncertainty while ensuring complementary modelling are suggested. These strategies would help in achieving meaningful progress with respect to the development of adaptive water resource systems, and also positively influence decision-making by relevant stakeholders.
Water demand management and losses in Garankuwa and Mabopane, South Africa
(2012-11-19) Mhlongo, Ntombie Thandazile; Otieno, Fredrick Alfred O.; Ochieng, George M.
This study attempted to address possible solutions to water demand management for the improvement of efficient use of a given volume of water while increasing water access to new users; application of water demand management tools both at the utility and end-user sides; and managing water losses in the distribution network which is a critical aspect of water demand management. The research was conducted in Garankuwa and Mabopane supplied by ODI Water Services in South Africa. This paper describes water resources in South Africa, water demand management tools in place and water supply to the ODI Water Services. It further presents data for the total purchases of water from Rand water and the final billed water at the utility, and water consumption patterns during the period of July to December 2009. This included attempts made to identify and quantify water losses in Garankuwa and Mabopane during the same period. Suggestions were made on how water losses can be reduced. In Garankuwa and Mabopane it was discovered that human perceptions on water demand management and water wastage through unaccounted-for-water together with the indigenous knowledge systems for the management of natural resources need to be altered as the country is water stressed.
Water security in South Africa: perceptions on public expectations and municipal obligations, governance and water re-use
(Creative Commons Attribution Licence, 2016-07-03) Sershen, S.; Rodda, N.; Stenström, Thor-Axel; Schmidt, S.; Dent, M.; Bux, Faizal; Hanke, N.; Buckley, C. A.; Fennemore, C.
South Africa is a water-scarce country with increasing pressure on its water resources. Urgent interventions are needed to protect water security within this rapidly developing country. This paper reports on an interdisciplinary Water Security Colloquium, convened by the South African Young Academy of Science in 2014. A selected group of water professionals from academia, civil society and local government was brought together to discuss water security under three focus themes: ‘public expectations and municipal obligations’, ‘water security and governance: challenges and advances’, and ‘water re-use: health and infrastructural considerations’. Participant perceptions were generated using a focus group methodology, combined with participatory data collection methods. Under each theme, inputs were categorised as ‘challenges’, ‘gaps in knowledge’, and ‘solutions/recommendations’ and these inputs were thereafter ranked in order of importance via a ‘voting’ process. Major challenges perceived included a lack of both skills and political will in government, a need to restore citizen trust in government intention and capability to deliver water-related services, and a failure to up-scale existing water re-use technology. Participants identified understanding of the process and implications of the Green and Blue Drop Programmes, knowledge transfer to the public, and the role of educators as major knowledge gaps. The top suggestions proposed included creating public awareness around and buy-in to initiatives to improve water security, accessible and user-friendly conversion of research results to implementation, and ensuring an active role for educators in creating awareness around water security. In view of the concerns identified, participants suggested as potential solutions: improving government and public understanding around water issues, incentivising water re-use and conservation, introducing rising block tariffs and improving human capacity development in the water sector. Developing the ecological infrastructure that protects both quantity and quality of water and building strong partnerships among all stakeholders were also recognised as key.
Women in selected rural municipalities: Resilience and agency against vulnerabilities to climate change
(Taylor and Francis, 2014-11-03) Meyiwa, Thenjiwe; Maseti, Thandokazi; Ngubane, Sizani; Letsekha, Tebello; Rozani, Carina
The role of rural women in eradicating poverty and ending hunger has been recognised by both scholars and practitioners. There is an acknowledgement that women serve a critical role in the agricultural labour force, subsistence farming, and rural development in sub-Saharan Africa, yet their central role in food security has been largely ignored, particularly in policy (Govender, 2012). Although much of the labour of rural women is not nationally defined as economically active employment these women still spend long hours in undervalued productive and reproductive work to ensure the well-being of their households. Linked to this role is the challenge of dealing with rapidly changing climatic conditions. Women assume primary responsibility in fetching water and wood for meal preparation, and in tilling the ground. They are among the most vulnerable groups to climate change as a result of their precarious environmental livelihoods. Using data from a workshop with rural women to discuss climate change and qualitative interviews with rural women in selected rural communities in the Eastern Cape and KwaZulu-Natal we explore the meaning of climate change. We report on the way climate change is understood, its effects on rural livelihoods and some responses to climate change problems experienced by the women in the communities. The women in the rural communities highlight that there are also social problems that have arisen from water scarcity. As a result of the household division of labour, rural girls confront particular challenges as they need to search further from home for water and are exposed to the risk of gender violence.