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Purpose The purpose of this paper was to determine the effect of route optimization on travel distance, travel time and fuel consumption of municipal solid waste (MSW) collection trucks. Design/methodology/approach The study modeled the existing waste collection routes in three local authorities in Ghana and proposed optimal routes using Esri’s ArcGIS Network Analyst Extension. The system generated optimal distances and times were validated by subjecting collection trucks to the optimal routes. Paired sample t-test was used to analyze the differences in means of the existing and optimal outcomes. The collected data were subjected to correlation and uncertainty analyses. Findings Results from the study indicated that weekly travel distance reduced by 81.27 km, translating into saving of 4.79 percent when trucks used the optimal routes. Travel time and fuel consumption reduced by 853.59 min and 145.86 L, making savings of 14.21 and 10.81 percent, respectively. Significant differences occurred between the means of the existing and optimal routes for travel time and fuel consumption, for each of the three local authorities. Research limitations/implications The study was conducted in Ghana using data collected from three local authorities. Practical implications Significant reduction of MSW collection cost can be achieved by waste management practitioners through route optimization. Originality/value The effect of route optimization on travel distance, travel time and fuel consumption has been established. Statistical analyses of the existing and optimal outcomes of the three local authorities have been provided. The findings from this study support the hypothesis that optimal routes reduce operating cost through savings in travel distance, travel time and fuel consumption.

The objectives of this study were to assess the black soldier fly larvae (BSFL) composting potential and to analyse the quality of organic fertilizer produced for agricultural purposes. The waste biodegradation was determined by varying waste feed treatment (2, 2.5, 3.0, 3.5, to 4 kg) and control treatment of (2 kg) of heterogeneous mixture of municipal organic solid waste from market, restaurant and households. Each of the setups received equal number of viable larvae (i.e. 2000) which were 5–6 days old. To analyse the nutrient concentration of the compost residues with BSFL, the substrate and final compost were evaluated based on the levels of NPK as well as the C:N ratio. To evaluate the toxic levels of the final compost in terms of heavy metals, the presence and levels of As, Cd, Fe, Pb and Ni were investigated. The analysis showed that there was high percentage increase of nitrogen, phosphorus and potassium levels, i.e. 41.2% (SD ± 0.71%), 32.4% (SE ± 0.2%) and 77.1% (SE ± 0.19%), respectively. It was found that the larvae degraded more than half of the total substrate within 2 weeks. The study showed a decrease in heavy metal concentrations after larvae composting. The study revealed that the concentration of NPK increased significantly among the treatment groups. The study further revealed that some of the heavy metals under investigation had reduced to an acceptable level according to the standards of both local and international regulatory bodies.

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.

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.

This study was carried out to assess the degradation and accumulation rates of fresh human excreta and how addition of anal cleansing materials affect performance during vermicomposting by Eisenia fetida and Eudrilus eugeniae. Vermicomposting setups consisting of two transparent containers (length 0.27 m, breadth 0.17 m and depth 0.12 m) stacked on top of each other were installed and operated under laboratory conditions. Earthworms, Eisenia fetida and Eudrilus eugeniae, were obtained from Green Cycle Technologies Limited in Accra, Ghana and the species verified and cultured before use. Fresh human excreta for feeding the experimental setups was collected from an Enviro-loo public toilet and 13 g applied to the setups daily. Similar setups were fed with 0.3 g of anal cleansing material in addition to the fresh excreta. A setup without any earthworms (NW) was set up as a control. Physicochemical characteristics of vermicompost accumulating in the setups were determined weekly for 28 days using standard laboratory procedures while the sludge accumulated in the various setups were weighed and recorded daily. One-way analysis of variance (ANOVA) and Post-hoc LSD tests were conducted to determine whether the differences in results between the two earthworm species and among setups with and without anal cleansing materials were statistically significant (p ≤ 0.05). The study showed 12.3% and 26.2% reduction in volatile solids in EE (Eudrilus eugeniae and excreta only) and EF (Eisenia fetida and excreta only) while ash content increased indicating good degradation. The percentage mass reductions recorded at the end of the fourth week were 67.5%, 58.8% and 40.5% in systems EE, EF and NW respectively, while reductions of 73.7% and 68.5% were realized in EEA (Eudrilus eugeniae with excreta and toilet paper) and EFA (Eisenia fetida with excreta and toilet paper) respectively. There was greater amount of sludge accumulated in systems without earthworms, 0.00020 m3 (59.5%) in NW, than in systems with earthworms where 0.00011 m3 (32.5%) and 0.00014 m3 (41.2%) were recorded for EE and EF respectively. The rate of accumulation in vermibeds EE and EF was relatively higher than in vermibeds with excreta and toilet paper (EEA and EFA). EEA and EFA recorded accumulation rates of 0.00009 m3 (26.3%) and 0.00011 m3 (31.5%) respectively. Complete removal of helminth eggs was not achieved in any of the treatment systems.

Many fruits including mango (Mangifera indica), key lime (Citrus aurantiifolia), African star apple (Chrysophyllum albidum) and African or bush pear (Dacryodes edulis) are nutritionally valuable as human food, however after consumption of the fruits, their seeds are discarded as wastes since they are of no commercial value and this results in disposal problems. Hence assessment of the constituents of such waste seeds will enable their application to be considered. In this study the proximate composition and phytochemical constituents of the seeds of Duncan mango (Mangifera indica), key lime (Citrus aurantiifolia), African star apple (Chrysophyllum albidum: C. acreanum) and African or bush pear (Dacryodes edulis: D.e.var.edulis) obtained from southern part of Nigeria have been investigated and compared for the four different seeds. The results obtained from the proximate analyses showed that the major constituent of the seeds are carbohydrates, proteins and fats. The key lime seed was found to contain more protein and fat compared to the other seeds while the African star apple seed was found to contain the least fat and more carbohydrate compared to the other seeds. The phytochemicals detected in all the seeds were tannins, glycoside, coumarins and phenols, however steroids were absent. Only African star apple seed contained saponins and alkaloids. The results further indicated that only the key lime seed was devoid of flavonoid and starch. Tannins in plants have been reported to be among the active agents that bring about coagulation and natural polymers (proteins, carbohydrate (starch) etc.) act as bridging flocculants. Saponins, flavonoids coumarins and phenols have also been reported to posses antibacterial potentials against pathogenic organisms. This study shows that these seeds contain these constituents and they are present in reasonable amount. Therefore it is concluded that these seeds can be investigated as possible coagulant aids for drinking water treatment.

On-site sanitation systems, the commonest sanitation technologies in low-income countries, are central to the elimination of open defecation in such countries. Nevertheless, their selection and application in the physical and socio-economic environment of low-income settings could be a complex and challenging task. Poorly designed and constructed facilities could pollute groundwater resources and create nuisances to the user and the general public. Meanwhile, local authorities in these countries often lack the human resource with the requisite technical capacity to analyse situations and recommend appropriate solutions. This calls for guidance in the most crucial technical decisions that affect the safe usage and environmental sustainability of on-site sanitation technologies. This Chapter reviews salient standards and guidelines for the selection of appropriate technologies, prevention of groundwater pollution, control of odor and fly nuisance, structural stability and safety of the latrine user.

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 cent, inorganic and residue was over 69 per cent and the paper and plastics was over 60 per cent. Research limitations/implications – The study suggests that the success of source separation programme hinges on education and economic incentives. It was noted that the sample size could be increased to enhance the accuracy of the data for prediction purpose. Practical implications – The findings showed there is potential for recycling through source separation programme in low-and middle-income communities. Public education and economic incentives are necessary for successful source separation programme. Originality/value – The paper provides insight into source separation to contribute to better understanding of how city authorities in developing countries could take advantage of economic incentives to scale-up recycling.

The recovery of recyclables from the waste stream is a vital factor to consider in any recycling scheme since it enhances the quality of recyclables and ensures efficient recycling schemes. This study was conducted in the Tamale Metropolis of Ghana to investigate incentive options that can promote municipal solid waste resource recovery to support policy decisions on the formalization of recycling scheme in the Metropolis. Solid waste source separation scheme was set up in four different waste management service zones in the Metropolis. The quantity of separated materials, set-out rate, as well as separation efficiency of the targeted materials in the scheme were also assessed. The result of the study indicated a high recovery factor for dry recyclables (53.97%) as against food waste (10.03%). There was a significant effect of incentives on waste material quantities. Significant differences also occurred in the set-out rates and separation efficiency. Moreover, the study showed that employing prize as a reward scheme in addition to the provision of a waste storage facility had a high propensity for waste material recovery. The study demonstrated that the quantity of waste materials that may be retrieved in a recycling scheme in different solid waste management service zones depends on the type of incentive employed in the scheme and the service zone considered.

The ventilated improved pit (VIP) latrine has the potential to address the challenge of access to improved sanitation in built-up low-income settings. However, its conventional technical design fails to address the needs and preferences of some users. The objective of this paper was to test the technical performance of modified engineering designs of the technology to respond to some preferences of toilet users. The entry of air from multiple windows in the superstructure and installation of insect screens in windows were tested in an experimental VIP latrine. The modified design achieved the recommended ventilation rate of 20 m3/h when a vent pipe diameter of 150 mm was used. The study concludes that adopting a multidirectional airflow design leads to a lower ventilation rate as compared to the conventional design. However, when fitted with the recommended size of vent pipe, this modified design achieves more than twice the recommended ventilation rate with or without an insect screen installed in the windows. Nevertheless, the practice in which 100 mm diameter vent pipes are used with insect screens installed in windows is likely to lead to odour problems due to inadequate ventilation through the vent pipe.

This paper explores how transition management processes can be designed to address the unsustainability of water, sanitation, and hygiene (WASH) services in informal settlements in cities in Sub-Saharan Africa. The unsustainability of services related to WASH in informal settlements in Sub-Saharan Africa is deeply embedded in current societal and governance structures, cultures, and practices, it is context-dependent and involves numerous actors with different interests. Based on a literature review and empirical work in Arusha (Tanzania), Dodowa (Ghana), and Kampala (Uganda), we identify five context dimensions that account for the unsustainability of WASH services: (a) multiplicity of WASH practices, structures, and arrangements, (b) governance capacities for WASH services and maintenance, (c) landownership for sustainable access to WASH, (d) public participation in decision-making related to WASH, and (e) socio-economic inequalities governing access to WASH. These dimensions pose numerous conceptual and application challenges for transition management. Based on these challenges, recommendations are formulated for the design of a contextualized, participatory transition management process that is not only functional, but also emancipatory.

To assess the suitability of water sources for drinking purposes, samples were taken from groundwater sources (boreholes and hand-dug wells) used for drinking water in the Dodowa area of Ghana. The samples were analyzed for the presence of fecal indicator bacteria (Escherichia coli) and viruses (Adenovirus and Rotavirus), using membrane filtration with plating and glass wool filtration with quantitative polymerase chain reaction (PCR), respectively. In addition, sanitary inspection of surroundings of the sources was conducted to identify their vulnerability to pollution. The presence of viruses was also assessed in water samples from the Dodowa River. More than 70% of the hand-dug wells were sited within 10 m of nearby sources of contamination. All sources contained E. coli bacteria, and their numbers in samples of water between dug wells and boreholes showed no significant difference (p = 0.48). Quantitative PCR results for Adenovirus indicated 27% and 55% were positive for the boreholes and hand-dug wells, respectively. Samples from all boreholes tested negative for the presence of Rotavirus while 27% of the dug wells were positive for Rotavirus. PCR tests of 20% of groundwater samples were inhibited. Based on these results we concluded that there is systemic microbial and fecal contamination of groundwater in the area. On-site sanitation facilities, e.g., pit latrines and unlined wastewater drains, are likely the most common sources of fecal contamination of groundwater in the area. Water abstracted from groundwater sources needs to be treated before use for consumption purposes. In addition, efforts should be made to delineate protected areas around groundwater abstraction points to minimize contamination from point sources of pollution.

The objective assessment of the level of odour in on-site sanitation systems is required when evaluating emerging technology options and maintenance practices. The purpose of this study was to measure the concentrations of hydrogen sulphide and ammonia as surrogates of odour using a portable gas detector, and assess whether the concentrations of the compounds correlate with the perception of users of the facilities. The Aeroqual 500 portable gas detector with hydrogen sulphide and ammonia sensor heads was used to measure the concentrations of the compounds in 88 private and seven communal latrines sampled from a peri-urban community in Ghana. The odour perception of 189 and 165 users of private and communal latrines, respectively, was assessed on an ordinal scale. It was found that the concentrations of hydrogen sulphide and ammonia measured with the gas detector reflected the known variation of odour levels among different technology options and the perceptions of the latrine users. The concentrations of hydrogen sulphide measured in the water closet, ventilated improved pit (VIP) and the simple pit latrines were 0.01, 0.03 and 0.13 ppm, respectively; those of ammonia were undetected for the water closet, and 0.30 and 3.27 ppm for the VIP and simple pit latrines, respectively. The Pearson correlation coefficient between hydrogen sulphide concentrations and user perception of odour (−0.234) was significant at 5 % level (p = 0.022) but that for ammonia was not. The results indicate that a portable hydrogen sulphide detector may be employed to objectively assess the effectiveness of new latrine designs and maintenance practices aimed at reducing odour in latrines.

Government failures call for private sector involvement in solid waste service provision which requires government regulation. Surveys of 1,300 households, 25 private companies and five local governments were conducted in five cities in Ghana to assess the regulatory practices in solid waste collection. The results showed that there were weak regulatory practices and non-adherence to contractual obligations. Service quality and cost recovery were affected by unsigned contracts, the long period before revision of collection fees and service charges, delayed payment of subsidy (more than a year) and no interest on money delayed. These weak regulatory practices affected investment in new tracks and did not provide incentive for private sector growth and development. But a gradual well-functioning system was emerging, with two competitive bidding and signing of contracts in two cities. The solution to the problem of solid waste management hinges on adherence to formal rules, such as competitive bidding, signing of and adhering to contracts, the use of appropriate cost recovery mechanisms, and the restructuring of institutional arrangements to enforce legislation.

This paper shows who the poor are in the slums of Accra and what kind of institutional arrangements they have to obtain drinking water and to solve their sanitary problems. The two most promising options were collaboration with the utility, which would provide standpipes or engage with private suppliers. We will analyse these options in more detail to show that they are serving the poor and can be benchmarked. That could lead to a situation where the achievements would be measured regularly and would imply that an increasing number of poor would be served, while the quality and price of the drinking water would be assured at a certain level. Similar arrangements are possible for the sanitation sector, where the Accra Metropolitan Authority is the responsible organisation.