Search Results (7)

Illegal solid-waste dumping (ISWD) is prevalent globally with adverse social and environmental impacts, particularly in poor communities. Understanding the extent, practices and perceptions of ISWD is needed to inform interventions. Using GIS techniques and household surveys, this study examined the prevalence of dumpsites, and perceptions of ISWD in a low-income neighbourhood of Komani, South Africa. A total of 120 dumpsites were encountered in green spaces, empty residential plots and street edges, suggesting illegal dumping of solid waste is widespread. More than half of the respondents (58%) disposed of household waste in undesignated sites or burnt it, attributing this to the non-collection of waste. Potential interventions suggested were largely technical, including regular collection of waste, and the provision of bins and plastic bags. The paper suggests approaches to addressing sustainable solid-waste management should consider the views of local communities, who are principal stakeholders in the solid-waste production and management mix. Full article

Background: Saudi Arabia is a leading country endorsing a sustainable future, from policymaking and investment to infrastructure development. One of the rising concerns in Saudi Arabia's Vision 2030 is solid waste management, especially in Makkah. The Solid Waste Collection Problem (SWCP) refers to the route optimisation of waste collection trucks visiting containers across various locations. Manually generated routes might contain some mistakes, and constructing and revising designed solutions can take a long time. Thus, there is a need to find optimal and fast solutions to this problem. Solving this problem demands tackling numerous routing constraints while aiming to minimise the operational cost. Since solid waste has a significant impact on the environment, reducing fuel consumption must be an objective. Methods: Thus, a mixed-integer programming model is proposed in this paper while using the time-oriented nearest neighbour heuristic. The goal is to investigate their performance on nine existing instances of SWCP in the city of Makkah. The proposed model is implemented in the Gurobi solver. The time-oriented nearest neighbour heuristic constructs the initial solution and is then re-optimised using Google OR-tools. Results: Using the greedy method to construct a solution for this problem generated better solutions when compared to the results obtained without the greedy method. Computational times are also improved by 55.7% on the problem instances. Conclusions: The findings confirm the competitive performance of the proposed method in terms of computational times and solution quality. Full article

The global demand for fuel keeps increasing daily. The massive depletion of fossil fuels and their influence on the environment as pollution is a severe problem. Meanwhile, food waste disposal is also a complex problem in solid-waste management since one-third of every food consumed is discarded as waste. The standard waste management methods, including food waste incineration and landfilling, are considered hazardous to the environment. Food waste constituents are majorly starch-based and contain various biomolecules, including sugar, lipids, proteins, vitamins, cellulose, etc. These polysaccharides can be hydrolysed into monosaccharides such as glucose, which can then be fermented using microorganisms to produce ethanol through the fermenting of sugars derived from enzymatic hydrolysis treatment of food wastes. The human food system is rich in starch, which can be a potential resource for bioethanol production. Full article

Solid-waste management is a challenge in many cities, especially in low-income countries, including Uganda. Simple and inexpensive strategies such as solid-waste segregation and recycling have the potential to reduce risks associated with indiscriminate waste management. Unfortunately, these strategies have not been studied and adopted in slums in low-income countries. This cross-sectional qualitative study, therefore, used the behavioral-centered design model to understand the drivers of recycling in Kampala slums. Data were coded using ATLAS ti version 7.0, and content analysis was used for interpreting the findings. Our findings revealed that the study practices were not yet habitual and were driven by the presence of physical space for segregation containers, and functional social networks in the communities. Additionally, financial rewards and awareness related to the recycling benefits, and available community support were found to be critical drivers. The availability of infrastructure and objects for segregation and recycling and the influence of politics and policies were identified. There is, therefore, need for both the public and private sector to engage in developing and implementing the relevant laws and policies on solid waste recycling, increase community awareness of the critical behavior, and create sustainable markets for waste segregated and recycled products. Full article

The paper examined the willingness of smallholder cassava processors to pay for value-added solid wastes management solutions in Nigeria. We employed a multistage sampling procedure to obtain primary data from 403 cassava processors from the forest and Guinea savannah zones of Nigeria. Contingent valuation and logistic regression were used to determine the willingness of the processors to pay for improved waste management options and the factors influencing their decision on the type of waste management system adopted and willingness to pay for a value-added solid-waste management system option. Women constituted the largest population of smallholder cassava processors, and the processors generated a lot of solid waste (605–878 kg/processor/season). Waste was usually dumped (59.6%), given to others (58.1%), or sold in wet (27.8%) or dry (35.5%) forms. The factors influencing the processors’ decision on the type of waste management system to adopt included sex of processors, membership of an association, quantity of cassava processed and ownership structure. Whereas the processors were willing to pay for new training on improved waste management technologies, they were not willing to pay more than US$3. However, US$3 may be paid for training in mushroom production. It is expected that public expenditure on training to empower processors to use solid-waste conversion technologies for generating value-added products will lead to such social benefits as lower exposure to environmental toxins from the air, rivers and underground water, among others, and additional income for the smallholder processors. The output of the study can serve as the basis for developing usable and affordable solid-waste management systems for community cassava processing units in African countries involved in cassava production. Full article

The conversion of biomass to high-density briquettes is a potential solution to solid waste problems as well as to a high dependence on fuel wood in developing countries. In this study, the potential of converting vegetable waste to briquettes using waste paper as a binder was investigated. A sample size of 30 respondents was interviewed using a self-administered questionnaire at the D-line fruit and vegetable market in Port Harcourt, Nigeria. Carrot and cabbage leaves were selected for briquetting based on their availability and heating value. This waste was sun-dried, pulverized, torrefied and fermented. Briquettes were produced with a manual briquette press after the processed vegetable waste was mixed with waste paper in four paper:waste ratios, i.e., 10:90, 15:85, 20:80 and 25:75. The moisture content, densities and cooking efficiency of the briquettes were determined using the oven-drying method, the water-displacement method, and the water-boiling test, respectively. There was no observed trend in moisture content values of the briquettes, which varied significantly between 3.0% and 8.5%. There was no significant variation in the densities, which ranged from 0.79 g/cm³ to 0.96 g/cm³ for all the briquette types. A degree of compaction above 300% was achieved for all the briquette types. Water-boiling test results revealed that 10:90 paper:sun-dried cabbage briquettes had the highest ignitability of 0.32 min. Torrefied carrot briquettes with 25% paper had the least boiling time and the highest burning rates of 9.21 min and 4.89 g/min, respectively. It was concluded that cabbage and carrot waste can best be converted into good-quality briquettes after torrefaction. Full article

Delhi generates about 8360 tons of municipal solid waste per day, and there is low compliance to rules regarding waste management. The objective of this paper was to understand the situation in Delhi with respect to the segregation, storage, collection, and disposal of household waste, and to assess the knowledge of the residents of Delhi, and their willingness to engage in solid-waste management. A stratified random sample, comprising 3047 respondents, was chosen for a questionnaire survey, covering all municipalities of Delhi, with socio-economic classification as the stratifying variable. Survey results indicate that 60% of residents do not know the difference between biodegradable and non-biodegradable waste, and only 2% of them segregate waste. Fifty-eight percent of respondents reported that the waste collector mixes the segregated waste, 97% of respondents reported that they sold items to an itinerant waste buyer, and 87% of households are covered by doorstep waste collection services. Abstract knowledge (general knowledge about waste management) is seen to have a significant correlation with willingness to engage in waste management. Differences between the socio-economic groups indicate that the highest (most educated and wealthy), as well as the lowest socio-economic category (least educated and poor), older age-groups, and women, have greater abstract knowledge. Socio-economic categories having higher abstract knowledge can be active participants in decentralized models of waste management. Full article