Browsing by Author "Bari, Niamul"

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    An analysis of factors that influence the spatial pattern of faecal matter flow in unsewered cities
    (Elsevier, 2025-05-25) Sultana, M. Sufia; Waine, Toby W.; Bari, Niamul; Tyrrel, Sean
    The management of sanitation systems in unsewered cities in low and middle income countries is a critical issue, yet it is unclear where the risk hotspots are and where interventions should be focused. This study utilised a prototype model, developed by the authors, to map the spatial pattern of faecal flow in Rajshahi city, a secondary city in northwest Bangladesh with a population around a million. This city serves as a representative example of 60 such secondary cities in Bangladesh and hundreds more in the economically developing region in Asia, Africa and Latin America. The model relies on assumptions that carry significant uncertainties; hence, the study employed a sensitivity analysis with multiple plausible scenarios to characterise these uncertainties, aiming to identify ways to improve the model further. Five major influencing factors on the spatial pattern of faecal flow were identified: the emptying of septic tanks, the use of soak pits, and sludge removal from drains, variations in faecal matter production by building types, and the presence or absence of toilets. These factors were shown to collectively have a significant impact (almost 50 % changed) on the model outcome, depending upon the assumptions made. The study offers insights that will guide future data collection efforts by emphasising the need to understand these specific influencing factors and their spatial pattern. Consequently, this research has broader implications for urban sanitation management as well as associated public health research like wastewater surveillance, risk assessment, and disease dynamics in similar urban settings, offering insights into areas of uncertainty that need to be addressed in future modelling efforts.
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    Assessing the reliability of open-source data used for spatial characterisation of urban sanitation infrastructure—a field study in Rajshahi, Bangladesh
    (Springer, 2025-03) Sultana, M. Sufia; Waine, Toby; Bari, Niamul; Tyrrel, Sean
    Urban sanitation in rapidly growing secondary cities remains a critical challenge, particularly in unsewered areas. This study evaluates the effectiveness of open-source data for modelling the sources and movement of faecal matter in such contexts, with a specific focus on Rajshahi, an unsewered secondary city in Bangladesh. By triangulating data from direct observations, key informant interviews (KIIs), and focus group discussions (FGDs), we assess the reliability of using open-source data to map faecal matter flow. The findings demonstrate an 80% alignment between the model’s simulated flow directions and actual field observations, highlighting the potential of using open-source data in urban sanitation management. Furthermore, the study reveals that 80% of buildings are connected to storm drains with many allowing faecal matter to overflow from septic tanks, thus posing a health risk. Despite efforts by the City Corporation to manage the drainage system through reactive measures like drain scraping and unblocking, blocked and overflowing drains remain prevalent, particularly during the rainy season. KIIs and (FGDs) highlight a lack of proactive maintenance and widespread unawareness of sanitation management systems. This integration of field-based insights with open-source data supports for a more proactive, data-driven approach to urban sanitation management in secondary cities, ultimately aiming to enhance public health and quality of life.
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    Sanitation infrastructure and faecal flow – SanIFFlow: a spatial mapping tool for integrated planning and management of sanitation in unsewered urban areas
    (Elsevier, 2025-07-01) Sultana, M. Sufia; Waine, Toby; Bari, Niamul; Tyrrel, Sean
    Proper sanitation is vital for public health, particularly in urban areas. However, planning and managing sanitation systems in secondary cities within economically developing countries presents persistent challenges, largely due to a lack of spatial understanding and representation. To address these challenges, this study introduces SanIFFlow (Sanitation Infrastructure and Faecal Flow), a spatial analytical approach focused on a city-scale, ward-level model. SanIFFlow provides an actionable insights into infrastructural attributes and faecal flow dynamics, tailored to the practical governance capacities of the city's existing management framework. By leveraging open-source data on buildings, population, and drainage network, the method offers a detailed spatial representation of faecal matter sources and movement pathways within urban catchments. This approach enables strategic sanitation planning and proactive management, identifying high-risk areas and supporting targeted interventions, such as ward-level infrastructure upgrades. SanIFFlow represents a scalable, data-driven tool designed to enhance urban sanitation management in resource-constrained settings.
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    Towards a new spatial representation of faecal sources and pathways in unsewered urban catchments using open-source data
    (IWA Publishing, 2023-03-14) Sultana, Mst Sufia; Waine, Toby; Bari, Niamul; Tyrrel, Sean
    Spatial representation of sanitation infrastructure and service coverage is essential for management planning and prioritising services. The provision of sanitation services in developing countries is inherently unequal because the sanitation infrastructure is lacking, and onsite sanitation is managed individually. Here, we developed a prototype method for creating a spatial representation of faecal sources and movement in a small area in Rajshahi city in northwest Bangladesh, which is representative of 60 other such secondary cities. We demonstrate an approach to estimate spatial variability in faecal production at the building scale by combining widely accessible buildings, ground elevation, and population data. We also demonstrate an approach to attribute potential faecal movement pathways by integrating drainage data, and faecal production at the building scale. We made use of free and open-source data and provide answers to the broader topic of spatial representation of faecal mobility in unsewered urban settings which has implications in a similar setting in developing countries.