James Darmey

This study examined the anaerobic co-digestion of the organic fraction of municipal solid waste (OFMSW), elephant grass (EG), and abattoir waste (AW) to boost biomethane production in Kumasi, Ghana. Analyses of physicochemical, ultimate, lignocellulosic, and organic fractions showed that the substrates have complementary traits suitable for anaerobic digestion. Elephant grass had high carbohydrate levels and low lignin, while abattoir waste supplied nitrogen-rich compounds to enhance nutrient balance during digestion. Biomethane potential (BMP) tests under mesophilic conditions with various substrate mixes revealed that EG ₁₀₀ generated a total methane yield of 275.55 mL CH₄ g⁻ ¹ VS, a 26.7% increase over OFMSW mono-digestion (217.51 mL CH₄ g⁻ ¹ VS). AW ₁₀₀ produced 155.52 mL CH₄ g⁻ ¹ VS. The co-digested mixture O50EG50 achieved the highest methane yield of 346.70 mL CH₄ g⁻ ¹ VS, representing a 59.4% increase over mono-digestion of OFMSW. The modified Gompertz model estimated an ultimate methane yield (G₀) of 531.37 mL CH₄ g⁻ ¹ VS for O ₅₀ EG ₅₀ , about 142.3% higher than for OFMSW alone, indicating that the co-digestion conditions need optimisation. These findings indicate that co-digesting OFMSW with elephant grass significantly enhances biomethane output and offers a sustainable waste-to-energy strategy for Ghana.

Sustainable recovery of aluminium from water treatment plant sludge (WTPS) offers a promising route for resource valorisation and waste reduction. In this study, Donnan dialysis (DD) is evaluated as a separation technique for recovering aluminium from a synthetic hydroxide-based feed simulating WTPS. A Box–Behnken design coupled with response surface methodology (BBD–RSM) was employed to model and quantify the effects of key operating parameters, namely feed pH, flow rate, initial aluminium concentration, runtime, and sweep solution concentration. Particle Swarm Optimisation (PSO) was integrated with the RSM framework to enhance global optimisation. The PSO approach predicted a maximum aluminium recovery of 99.1% under optimal conditions (pH 4.74, flow rate 98.60%, feed concentration 1313.3 ppm, runtime 21.5 h, and sweep concentration 0.25 M). Experimental validation yielded a recovery efficiency of 90.4%, corresponding to a deviation of 9.2% at a 95% confidence level with R² = 0.9632 and predicted R² = 0.9072. The results demonstrate that DD is an effective and scalable approach for recovering aluminium from hydroxide-rich sludge matrices, while PSO provides a robust optimisation strategy to address the nonlinearities inherent in membrane-based separation processes. This hybrid modelling framework advances process optimisation methodologies and supports the development of sustainable sludge-to-resource technologies in water treatment systems.

Anaerobic digestion (AD) is an effective technology for sustainable waste management, renewable energy production and resource recovery within a circular economy. This study offers a systematic bibliometric review of global advances in AD research and assesses their relevance to Ghana. Using the PRISMA framework, the literature from 2011 to 2025 was sourced from the Scopus database and analysed through bibliometric and thematic methods. The review emphasises four key factors affecting AD performance: municipal solid waste as feedstock, pretreatment technologies, biochemical methane potential (BMP) assessment and process optimisation. Studies were included if they addressed any of these themes. Non-English publications, inaccessible full texts and papers lacking bibliographic metadata were excluded. After screening 3424 records, 61 studies were included in the systematic review. After metadata screening, 3374 of the 3424 retrieved records were retained for bibliometric analysis. Results show that municipal solid waste, food waste, agricultural residues and sewage sludge are promising sources for biogas generation. Pretreatment techniques, including thermal, chemical, mechanical and biological, significantly enhance substrate biodegradability and methane production. BMP assessment is a reliable way to gauge feedstock suitability and energy recovery potential. Optimising parameters like pH, temperature, organic loading, hydraulic retention time and co-digestion ratios improves process stability and biogas yield. The review highlights the increasing use of modelling and optimisation to boost digester performance and facilitate scale-up. In Ghana, abundant organic waste offers significant opportunities for biogas development. Employing advanced feedstock characterisation, pretreatment, BMP evaluation and optimisation can improve AD efficiency, support renewable energy, reduce waste disposal issues and promote Ghana’s shift toward a sustainable circular bioeconomy.

Anaerobic digestion (AD) is a sustainable method of treating organic waste to generate methane-rich biogas. However, the complex lignocellulosic nature of organic waste in most cases limits its biodegradability and methane potential. This review evaluates pretreatment technology to optimize AD performance, particularly in developing countries like Ghana, where organic waste remains underutilized. A narrative synthesis of the literature between 2010 and 2024 was conducted through ScienceDirect and Scopus, categorizing pretreatment types as mechanical, thermal, chemical, biological, enzymatic, and hybrid. A bibliometric examination using VOSviewer also demonstrated global trends in research and co-authorship networks. Mechanical and thermal pretreatments increased biogas production by rendering the substrate more available, while chemical treatment degraded lignin and hemicellulose, sometimes more than 100% in methane yield. Biological and enzymatic pretreatments were energy-consuming and effective, with certain enzymatic blends achieving 485% methane yield increases. The study highlights the synergistic benefits of hybrid approaches and growing global interest, as revealed by bibliometric analysis; hence, the need to explore their potential in Ghana. In Ghana, this study concludes that low-cost, biologically driven pretreatments are practical pathways for advancing anaerobic digestion systems toward sustainable waste management and energy goals, despite infrastructure and policy challenges.

Finding sustainable solutions to the increasing waste generation in Ghana has received a lot of attention in recent years. Through several waste-to-energy processes, the energy potential of municipal solid waste has recently witnessed significant technological advancements. The Renewable Energy Master Plan has projected the production of about 122 MWp from waste-to-energy installations by 2030 in Ghana. To help policymakers and engineers achieve national goals, this paper reviews the waste generation in Ghana estimated from 2010 to 2030 and the status of various bioenergy technologies in Ghana. This paper further estimates the energy recovery potential of municipal solid waste in Ghana under incineration, anaerobic digestion, and landfill gas recovery technologies. The review establishes that, by 2030, municipal solid waste generation will increase by 123% of the 2023 quantities and may produce 1484.25 MW of installed electricity capacity and 13,002.03 GWh per year, which would amount to nearly 59% of Ghana’s 2030 renewable energy target. Additionally, it was determined that anaerobic digestion, incineration, and landfill gas recovery technologies, when properly developed, will add 105.33 MW, 301.4 MW, and 377.31 MW of installed electrical capacity, respectively, to Ghana’s energy mix in 2028.

The use of antibiotics is widespread throughout the world, and Ghana is not an exception. They are one of the most frequently prescribed medications. Antibiotic residue concentrations are rising in the environment and are found in practically all water bodies, including lakes and rivers, because of inadequate management of residential and medical wastes. Contrarily, there is a substantial chance of medication toxicity and resistance. Therefore, removal of these pollutants from water bodies is essential, yet conventional wastewater or water treatment methods frequently fall short of efficiently removing these chemicals. Antibiotics will be used as a case study in this chapter to discuss the concentration of pharmaceutical pollutants in the environment, specifically in Ghanaian waterbodies, and risk evaluations of these pollutants. Additionally, this chapter will look into the possible removal technologies report and establish the present investigation on removing these pollutants with microplastics.

Coconut shells are used as precursors for preparation of activated carbons. The shells could vary in terms of their maturity. The influence of the maturity of the shells on gold adsorption efficiencies of derived activated carbons (ACs) from gold di-cyanide solution was investigated. The shells were pyrolysed at 900 ºC and the resulting chars were activated in steam at the same temperature for different durations. Assessment of the properties of the derived ACs revealed that; the hardness, gold adsorption capacities and rates of gold adsorption of the ACs depended on the maturity of the shells. The more matured the shells the harder the AC. The relative hardness and gold adsorption rates of the mature coconut shells activated carbons, HMand RM, respectively and those of the less mature shells, HLand RL, respectively were in the order of HM >HL and RM >RL. The relative hardness of the ACs derived from the more mature and less mature shells after 3 hrs activation were 99.3% and 94.0%, respectively and the gold adsorption rates were 5.78 mg Au/hr/gand 4.95 mg Au/hr/g, respectively. The adsorption rates and relative hardness depended on the duration of activation, where longer activation times resulted in increase in the adsorption rates and a decrease in relative hardness of the derived ACs. Keywords: Adsorption, Activated Carbon, Coconut Shells, Maturity, Relative Hardness