This paper presents a comparative review of arsenite (As(III)), arsenate (As(V)), and fluoride (F⁻) for a better understanding of the conditions and factors during their adsorption with focus on (i) the isotherm adsorption models, (ii) effects of pH, (iii) effects of ionic strength, and (iv) effects of coexisting substances such as anions, cations, and natural organics matter. It provides an in-depth analysis of various methods of arsenite (As(III)), arsenate (As(V)), and fluoride (F^-) removal by adsorption and the anions’ characteristics during the adsorption process. The surface area of the adsorbents does not contribute to the adsorption capacity of these anions but rather a combination of other physical and chemical properties. The adsorption capacity for the anions depends on the combination of all the factors: pH, ionic strength, coexisting substances, pore volume and particles size, surface modification, pretreatment of the adsorbents, and so forth. Extreme higher adsorption capacity can be obtained by the modification of the adsorbents. In general, pH has a greater influence on adsorption capacity at large, since it affects the ionic strength, coexisting anions such as bicarbonate, sulfate, and silica, the surface charges of the adsorbents, and the ionic species which can be present in the solution.

The appalling state of Liberia’s municipal solid waste management system (MSWM) is the motivation for this review and analysis. Solid waste management protocols and system dynamic modeling support policy development as it uses waste prevention to explain the complex waste management systems and suggests methods for effective management. However, creating an effective waste system goes beyond the formulation of policies and legislation; it involves financial and technological proficiency, skilled human capacity, technical, social, resource recycling, educational awareness programs, and active public participation. Because of urbanization, Liberia’s municipal solid waste (MSW) problems have become heightened, thereby impacting the economic, social, and political fabric of society by overburdening infrastructure and social facilities. The impact of urbanization must be addressed because urbanization, amongst several factors, including unsustainable management of MSW, degrades the environment and presents risks to public health. The purpose of this review was to highlight the current waste management activities in Liberia and provide information to the readers about the challenges facing the waste management sector and the challenges impeding the development of a sustainable waste management system. In Liberia, waste management activities are getting worse daily due to shortage of a comprehensive waste management framework, the absence of guidelines regarding the responsibilities of waste generators, and the decision-makers' lack of intent to design and implement a sustainable and integrated management system. Recommendations for collaborative efforts are made by focusing on delivering a waste strategy which concentrates on waste minimization, recycling, resource recovery, and promoting sustainable waste management practices for communities, small businesses, corporations, and government institutions in Liberia and other developing countries.

This mini-review analyses food losses and waste (FLW) management in low- and middle-income countries (LMICs) and identifies potential strategies to improve FLW management efficiency on the African continent. To achieve this aim, a search of grey and published scientific literature-case studies, feasibility studies, theses, peer-reviewed journals, governments and technical reports was performed. Food waste (FW) per capita in sub-Saharan Africa (SSA) was determined to be between 6 and 11 kg capita⁻¹ year⁻¹. Factors militating against FLW management include a lack of infrastructure, waste reduction and mandatory waste management plans, financial support for food redistribution programmes, awareness and a lack of knowledge of FW management and effective approaches. Poor recovery systems, a lack of incentives in FW recycling programmes, a lack of a regulatory and policy framework and institutional weaknesses as well as a lack of sufficient and appropriate education programmes to improve FW source separation and collection rates are all significant challenges in the African region, with negative consequences for the environment and public health. Except for fuel conversion and food scraps for digestion to recover energy, there is a huge potential for composting and using FW as a digestate, which could eventually lead to a reduction in the amount of FW being landfilled or incinerated. The study explores potential interventions to reduce amount of FLW and form a basis for future research in this field and improving FW management efficiency in LMCs, especially on the continent of Africa. It also provides information that could assist researchers, policymakers and decision-makers reduce amount of FLW, aid in the utilization of FW for energy production, and reduce greenhouse gas emissions in the continent, as well as support the achievement of other sustainable development goals, such as 12.3, which is particularly important in the context of the African continent, which is dependent on food imports.

The population of Monrovia is increasing accompanied by rapid urbanization. Due to rapid urbanization, economic development, higher living standards and changes in consumption patterns and lifestyle, the generation rate of waste has increased. Mismanagement of solid waste tends to hinder any progress towards environmental sustainability. This study endeavored to determine the adequacy of waste management services in the city, explore the linkage between population and development and the increase in the generation of wastes. The study assessed both qualitatively and quantitatively behavioral factors including knowledge, attitude and practices of solid waste management, collaboration among stakeholders, and challenges related to sustainable waste management in Monrovia. Households were selected randomly (simple and stratified) to show the socio-economic groups in the city. Purposive sampling was used to identify key informants or personnel in charge of waste management and the use of questionnaires captured vital information on waste management in the city. The major findings showed the main proportion of waste generated in Monrovia was organic refuse (40.2%) followed by plastic (14.2%). Waste generated are inadequately disposed of due to the inadequate collection system, as large fragment of waste remain uncollected resulting in open dumping and burning of wastes. These waste management challenges have become heightened as a result of insufficient technology to ensure proper management, low budgetary allocations for effective waste management, lack of skilled professionals, poor implementation of regulations to ensure adequate management, and poor public awareness.

The ineffective management of household solid waste (HSW) in most developing cities in Africa including Monrovia has become a major issue threatening the environment and public health. In response to these waste challenges, developed countries have embarked upon major environmental reforms, and have made advances in best practices and sustainable management of their Municipal Solid Waste (MSW). However, in most developing countries like Liberia, such environmental reforms have not been initiated and therefore the situation has become compounded; this is due to several factors impeding the development of a sustainable municipal solid waste system. This study, therefore, aims to critically analyze the influencing factors of solid waste management; the characteristics of household waste and suggest management solutions for effective and sustainable management. Results from the analysis of data, using The Ordinary Least Square Regression (OLS) method estimates the average household waste per capita generation as 0.76kg/capita/day. Regarding the composition of the waste stream, the results show that 67% of the waste sampled from Monrovia is biodegradable and mostly comprised of high wet weight and high moisture content kitchen waste. On the other hand, the remaining percentage is mostly non-degradable but recyclable materials such as glass ceramics and metals. This suggests that due to the high moisture content in the waste, samples are suitable for composting and other mechanical and biological management options. Using the stratified sampling method, 300 households were chosen. Multiple regressions were conducted to determine the relationship between waste generation and socio-economic factors and these showed that the effect of income, household size and the environmental concern on HSW generation is statistically significant at a 1% significance. However, further findings revealed a negative relationship between income and HSW generation at a 1% level of significance. These findings provide new insight regarding the role of socio-economic characteristics affecting the generation of household waste in Monrovia.