Browsing by Author "Dodoo-Arhin, David"

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Assessment of fluoride removal in a batch electrocoagulation process: A case study in the Mount Meru Enclave
(Elsevier B.V., 2021-03-04) Mureth, Risala; Machunda, Revocatus; Njau, Karoli; Dodoo-Arhin, David
The presence of excessive amounts of fluoride than prescribed standards has been reported in various sources of domestic water supply around the slopes of Mount Meru and other parts in Tanzania. Efforts to remove the excessive fluoride have been carried out using various technologies. In this study, electrocoagulation experiments were carried out to assess its efficiency on fluoride removal. The fluoride concentration tested ranged from 1.37 to 48 mg/L in both synthetic and natural waters. The voltage applied in the electrocoagulation (EC) process ranged from 0 to 50 V while maintaining pH values of 4 to 9. The representative experimental results for the Ngarenanyuki river water with initial fluoride concentration of 29.5 mg/L accomplished a removal efficiency of 90% at an optimal electrolysis time of 30 min, an applied voltage of 30 V and an optimal pH of 6. The method showed efficient fluoride removal in water to allowable limits by World Health Organization (WHO) and Tanzania Bureau of Standards (TBS) (1.5 mg/L). Despite the voltage applied (30 V), the pH at neutrality remained unchanged thus making the process more efficient. At this voltage (30 V) the process has been reported previously also to have the capability of disinfecting the water and hence rendering such water safe for use
Managing non-revenue water in Mwanza, Tanzania: A fast-growing sub-Saharan African city
(Elsevier Ltd., 2021-07) Shushu, Upendo; Komakech, Hans; Dodoo-Arhin, David; Ferras, David; Lal Kansal, Mitthan
High non-revenue water (NRW) and unreliable water supply services are major challenges in operations of the water infrastructure of most fast-growing cities in developing coun- tries. In this study, an analysis of the existing distribution network was carried out to investigate its performance concerning water loss reduction and system improvement. A high percentage of NRW (50%) was found in a selected district metering area (DMA) com- pared to the city’s entire network (37%). About 87% of the NRW was contributed by real losses in the DMA, while about 52% of the nodal junctions had pressure above the recom- mended thresholds. The high pressure was responsible for the observed leakages and pipe bursts in the DMA. Optimization of pressure by using pressure-reducing valves as well as changing the network topology minimized the potential leakages to 46%. Also, flow veloci- ties in about 83% of the pipes were found inadequate leading to poor water quality due to water stagnation. Low velocities were due to oversized indicating incidence of unplanned spatial and temporal expansion of the distribution network. This study, therefore, revealed that a comprehensive zone by zone assessment of water distribution network can improve the management of non-revenue in unplanned urban areas which is in line with ensuring the availability and sustainable management of water and sanitation for all.