Evaluating Access to Potable Water and Basic Sanitation in Ghana's Largest Urban Slum Community: Old Fadama, Accra

Access to potable water and basic sanitation in urban poor communities remains a critical issue in the developing world. This paper examines access to potable water and basic sanitation in Ghana's largest urban slum and the level of commitment by stakeholders to improve the current conditions. It drew on an extensive field survey, interviews, focus group discussions and drinking water quality analyses. The study revealed that the community depend entirely on vended water for their daily water supply needs. Apart from being sold at exorbitant prices, the sources of drinking water is also contaminated with attendant health risks. Household toilets are non-existent in the community and thus residents rely exclusively on public latrines; KVIP and pan latrines which are also inadequate. This partly accounts for the practice of open defecation in the community with possible health effects such as diarrhea and cholera. Indiscriminate dumping of refuse, choked drains and pools of stagnant water are ubiquitous thereby posing health threats. There is a low level of commitment to improving access to water and sanitation in the community by major stakeholders in spite of the glaring health effects. The outcomes of this study will be useful to relevant stakeholders and authorities in developing suitable strategies for improving access to water and sanitation for urban poor communities. Keywords: Accra, health, Old Fadama, sanitation, slum, wate

Fate and transport of nutrients in groundwater and surface water in an urban slum catchment, Kampala, Uganda; Dissertation, UNESCO-IHE Institute for Water Education, Delft.

Urban informal settlements or slums are growing rapidly in cities in sub-Saharan Africa. Most often, a sewer system is not present and the commonly-used low-cost onsite wastewater handling practices, typically pit latrines, are frequently unplanned, uncontrolled and inefficient. Consequently, most households dispose of their untreated or partially treated wastewater on-site, generating high loads of nutrients to groundwater and streams draining these areas. However, the fate of nutrients in urban slums is generally unknown. In excess, these nutrients can cause eutrophication in downstream water bodies.The aim of this study was to understand the hydro-geochemical processes affecting the generation, fate and transport of nutrients (nitrogen and phosphorus) in a typical urban slum area in Kampala, Uganda. The approach used combined experimental and modeling techniques, using a large set of hydrochemical and geochemical data collected from shallow groundwater, drainage channels and precipitation.The findings showed that both nitrogencontaining acid precipitation and domestic wastewater from slum areas were important sources of nutrients in urban slum catchments. For nutrients leaching to groundwater, pit latrines retained over 80% of the nutrient mass input while the underlying alluvial sandy aquifer was also an effective sink of nutrients where nitrogen was removed by denitrification and anaerobic oxidation and phosphorus by adsorption to calcite. In surface water, nutrient attenuation processes were limited. The study demonstrates that groundwater may not be that important with regard to eutrophication of downstream ecosystems, implying that management interventions in slum areas should primarily focus on reducing nutrients released into drainage channels. This research is of broad interest as urbanization, and particularly the growth of peri-urban areas is an ongoing trend and many cities in developing countries lack adequate sanitation systems

Phosphorus transport and retention in a channel draining an urban, tropical catchment with informal settlements

rban catchments in sub-Saharan Africa (SSA) are increasingly becoming a major source of phosphorus (P) to downstream ecosystems. This is primarily due to large inputs of untreated wastewater to urban drainage channels, especially in informal settlements (or slums). However, the processes governing the fate of P in these catchments are largely unknown. In this study, these processes are investigated. During high runoff events and a period of base flow, we collected hourly water samples (over 24 h) from a primary channel draining a 28 km2 slum-dominated catchment in Kampala, Uganda, and from a tertiary channel draining one of the contributing slum areas (0.54 km2). The samples were analysed for orthophosphate (PO4-P), particulate P (PP), total P (TP), suspended solids (SS) and hydrochemistry. We also collected channel bed and suspended sediments to determine their geo-available metals, sorption characteristics and the dominant phosphorus forms. Our results showed that the catchment exported high fluxes of P (0.3 kg km2 d?1 for PO4-P and 0.95 for TP), which were several orders of magnitude higher than values normally reported in literature. A large proportion of P exported was particulate (56%of TP) and we inferred that most of it was retained along the channel bed. The retained sediment P was predominantly inorganic (>63% of total sediment P) and consisted of mostly Ca and Fe-bound P, which were present in almost equal proportions. Ca-bound sediment P was attributed to the adsorption of P to calcite because surface water was near saturation with respect to calcite in all the events sampled. Fe-bound sediment P was attributed to the adsorption of P to iron oxides in suspended sediment during runoff events given that surface water was undersaturated with respect to iron phosphates. We also found that the bed sediments were P-saturated and showed a tendency to release P by mineralisation and desorption. During rain events, there was a flushing of PP which we attributed to the resuspension of P-rich bed sediment that accumulated in the channel during low flows. However, firstflush effects were not observed. Our findings provide useful insights into the processes governing the fate and transport of P in urban slum catchments in SSA.Water ManagementCivil Engineering and Geoscience

Transport and retention of phosphorus in surface water in an urban slum area

The transport of excessive phosphorus (P) discharged from unsewered informal settlements (slums) due to poor on-site sanitation is largely unknown. Hence, we investigated the processes governing P transport in a 28 km2 slum-dominated catchment in Kampala, Uganda. During high runoff events and a period of base flow, we collected hourly water samples (over 24 h) from a primary channel draining the catchment and from a small size tertiary channel draining one of the contributing slum areas (0.5 km2). Samples were analyzed for orthophosphate (PO4-P), particulate P (PP), total P (TP) and selected hydro-chemical parameters. Channel bed and suspended sediments were collected to determine their sorption potential, geo-available metals and dominant P forms. We found that P inputs in the catchment originated mainly from domestic wastewater as evidenced by high concentrations of Cl (36–144 mg L-1), HCO3 and other cations in the channels. Most P discharged during low flow conditions was particulate implying that much of it was retained in bed sediments. Retained P was mostly bound to Ca and Fe/Al oxides. Hence, we inferred that mineral precipitation and adsorption to Ca-minerals were the dominant P retention processes. Bed sediments were P-saturated and showed a tendency to release P to discharging waters. P released was likely due to Ca-bound P because of the strong correlation between Ca and total P in sediments (r2 = 0.9). High flows exhibited a strong flush of PP and SS implying that part of P retained was frequently flushed out of the catchment by surface erosion and resuspension of bed sediment. Our findings suggest that P accumulated in the channel bed during low flows and then was slowly released into surface water. Hence, it will likely take some time, even with improved wastewater management practices, before P loads to downstream areas can be significantly reduced.Water ManagementCivil Engineering and Geoscience