Sampson Oduro-Kwarteng

Groundwater as a strategic resource for improved resilience: a case study from peri-urban Accra

Water insecurity is a growing concern globally, especially for developing countries, where a range of factors including urbanization are putting pressure on water provisioning systems. The role of groundwater and aquifers in buffering the effects of climate variability is increasingly acknowledged, but it can only be fully realized with a more robust understanding of groundwater as a resource, and how use of it and dependency on it differ. Accra and its hinterland exemplify an African city with chronic water shortages, where groundwater resources offer opportunities to improve resilience against recurring droughts and general water insecurity. Based on a mixed-methods study of a peri-urban township, it was found that for end users, particularly poor urban households, resilience is an every-day matter of ensuring access from different sources, for different purposes, while attention to drinking water safety is falling behind. Planners and decision makers should take their cue from how households have developed coping mechanisms by diversifying, and move away from the focus on large infrastructure and centralized water supply solutions. Conjunctive use, managed aquifer recharge, and suitable treatment measures are vital to make groundwater a strategic resource on the urban agenda.

Source separation and recycling potential of municipal solid waste in Ghana

Purpose – The purpose of this paper is to assess the waste characteristics and separation efficiency of source separation of household waste in low- and middle-income communities in Kumasi Metropolis, Ghana. Design/methodology/approach – A sample of 60 households participated in the household survey, education on source separation and pilot source separation exercise. The solid waste was sorted into six fractions and three recycling categories (biodegradable; paper and plastic; residue). Findings – The mean generation rate of solid waste was 0.52±0.26 kg/per capita/day for the low-income community and 0.65±0.27 kg/per capita/day for the middle-income community. The waste fractions in the communities (low, middle income) were biodegradable organics (59.15, 65.68 per cent), plastics (11.01, 10.68 per cent), papers (3.15, 4.51 per cent), glass (0.89, 2.57 per cent), metals (0.96, 4.63 per cent) and miscellaneous (24.84, 11.93 per cent), respectively. The separation efficiency for organic category was 70 per ...

The latrine ownership ladder: A conceptual framework for enhancing sanitation uptake in low-income peri-urban settings

Purpose – The purpose of this paper is to present the latrine ownership ladder as a conceptual policy framework to enhance sanitation uptake in low-income peri-urban areas. Design/methodology/approach – The paper draws from literature and a case study in a Ghanaian peri-urban community to highlight the challenges that undermine sanitation uptake in low-income peri-urban areas and the prospects of various levels of facility sharing as conceived in the latrine ownership ladder approach. Findings – The authors argue that the infrastructural and other socio-economic challenges of low-income peri-urban areas prevent some households from acquiring their own latrines. For such households, a more responsive approach to latrine promotion and prevention of open defecation would be the recognition of shared ownership regimes such as co-tenant shared, neighbourhood shared and community shared, in addition to the promotion of household latrines. The paper identifies provision of special concessions for peri-urban area...

Optimal Routing of Solid Waste Collection Trucks: A Review of Methods

This paper reviews the effect of applying optimization methods on the collection process of solid waste, with particular interest in mathematical programming and geographic information system approaches in developing countries. Mathematical programming approaches maximize or minimize an objective function for improvement in procedure, to ensure operational efficiency and also serve as decision support tools. They however provide partial solutions when implemented in reality and cannot fully handle road network constraints. Geographic information system approaches allow processing of additional considerations, often ignored in other methods, such as the street network modeling. Incorporating environmental pollution consideration is very challenging in this approach, the vehicle routing problem solver encountering limits for large data. For enhanced efficiency of the vehicle routing systems, studies should further focus on incorporating all network constraints, environmental pollution considerations, and impact of land use changes on routing.

Optimising ventilation to control odour in the ventilated improved pit latrine

The rate of ventilation through the vent pipe of a ventilated improved pit latrine is the main technical factor that determines its efficiency in odour control aside the maintenance and cleaning practices of the users. Even though the factors affecting the ventilation rate have been well researched, they have not been previously related in a mathematical model to quantify the relative effect of the various factors on the ventilation rate. The objective of this paper is to develop such a model that could be used to optimise and predict the ventilation rate as a function of relevant design criteria and weather conditions. The ventilation rates produced by various design modifications in an experimental ventilated improved pit latrine were measured under monitored weather conditions. A linear regression model was used to assess the relative effect of the various design modifications and the elements of weather on the ventilation rate. It was found that the diameter of the vent pipe is the most important factor which accounts for 53% of variations in the ventilation rate, followed by the external wind speed, which accounts for 25% of changes in ventilation. The provision of windows in other sides of the superstructure other than the windward side leads to a reduction of 32% in the ventilation rate and accounts for 9% of the variations in the ventilation rate. A regression model developed in this study could be used to optimise and predict the ventilation rate based on a set of design criteria and meteorological data.

Cost drivers and functions for municipal solid waste collection systems in Ghana

The collection of municipal solid waste accounts for 60% to 80% of total management cost. This study determined the factors driving operating cost and developed cost functions for municipal solid waste collection systems in Ghana. Data on cost variables from seventy systems were used to estimate the parameters of log-linear cost functions. Results from the study led to the conclusion that quantity of waste collected, fuel consumed and distance travelled increase significantly and explain about 63.0% of the variation in operating cost. The amount of fuel consumed and quantity of waste collected varied significantly and explained about 67.4% of the variation in operating cost of systems from low waste generating sources. For high waste generating sources, the distance travelled, fuel consumed and quantity of waste collected significantly and better explained (85.4%) the variation in operating cost. This can be attributed to the fact that such systems are from places with better facilities. The cost function for high waste generating sources can comparatively better aid decision making in terms of operations, management, investment and policy actions. Cost-effective solid waste collection schemes should therefore consider efficient management of fuel consumed, quantity of waste generated and distance travelled.