The continual generation and discharge of waste are currently considered two of the main environmental problems worldwide. There are several waste management options that can be applied, though anaerobic digestion (AD) process technology seems to be one of the best, most reliable, and feasible technological options that have attracted remarkable attention due to its benefits, including the generation of renewable energy in the form of biogas and biomethane. There is a large amount of literature available on AD; however, with the continuous, progressive, and innovative technological development and implementation, as well as the inclusion of increasingly complex systems, it is necessary to update current knowledge on AD process technologies, process variables and their role on AD performance, and the kinetic models that are most commonly used to describe the process-reaction kinetics. This paper, therefore, reviewed the AD process technologies for treating or processing organic biomass waste with regard to its classification, the mechanisms involved in the process, process variables that affect the performance, and the process kinetics. Gazing into the future, research studies on reduced MS-AD operational cost, integrated or hybrid AD-biorefinery technology, integrated or hybrid AD-thermochemical process, novel thermochemical reactor development, nutrient recovery from integrated AD-thermochemical process, and solid and liquid residual disposal techniques are more likely to receive increased attention for AD process technology of biomass wastes.

The use of biobased heterogeneous catalysts made from agricultural waste for producing biodiesel has gained attention for its potential to create a sustainable and low-cost process. The blending of two or more biomass residues to create more viable biobased catalysts is still in its early stages. In this study, a Biobased Composite Heterogeneous Catalyst (CHC) was made by blending the shells of periwinkle (PWS), melon seed-husk (MSH), and locust bean pod-husk (LBP) at a mixing ratio of 67:17:17 using Simplex Lattice Design Mixture, that was then calcined for 4 h at 800 °C. The chemical, structural, and morphological components of the CHC were characterized via XRF, XRD, SEM-EDX, BET, TGA/DSC, and FTIR to assess its catalytic potential. The CHC was employed to synthesize biodiesel from palm kernel oil, and the process optimization was conducted using the Taguchi approach. The XRF analysis showed that the catalyst had 69.049 of Calcium (Ca) and 9.472 of potassium (K) in their elemental and oxide states as 61.592% calcium oxide and 7.919% potassium oxide. This was also supported by the EDX result, that showed an appreciable value of 58.00% of Ca and 2.30% of magnesium, that perhaps provided the active site in the transesterification reaction to synthesize biodiesel. The morphological and physisorption isotherms via SEM and BET showed mesoporous structures in the CHC that were made up of nanoparticles. A high maximum biodiesel yield of 90.207 wt.% was attained under the optimized process conditions. The catalyst could be reused for up to four cycles, and the biodiesel produced met both ASTM D6751 and EN 14214 standards for biodiesel. This study demonstrates that blending PWS, MSH, and LBP waste materials can produce high-quality biodiesel without the need for additional catalysts.

The paper attempted to examine the impact of manufacturing sector output on economic growth in Nigeria from 1981 to 2016. The study employed secondary data sourced from the Central Bank of Nigeria statistical bulletin for Autoregressive Distributed Lag (ARDL) model and the Granger causality techniques on RGDP, manufacturing capacity utilization (MCU), manufacturing output (LMO), government investment expenditure (GINVEXP), money supply (LM2) and interest rate (INR). Evidence of long-run and short-run relationships among the variables was established. The results showed that MCU has positive influence on RGDP while LMO also affects RGDP positively. It also showed that GINVEXP has negative effects on RGDP whereas LM2 influenced RGDP positively. Moreover, the result indicated a unidirectional causality between RGDP and MCU, LMO and LM2. Based on the above, the study suggest government should intensify efforts to promote socio-economic infrastructural, macroeconomic and institutional framework in Nigeria to provide favourable environment for external and domestic institutions interactions; so harnessed mobilized funds effectively towards productive manufacturing sector.

For centuries, state posts distinguished themselves as dependable institutions to citizens and governments within the life cycle of societies prior to the emergence of alternative mail delivery channels. The demand for traditional postal services has been on the decline due to changing customer demands, competition, unfavourable business divergence and the substitution of paper mail with digital alternatives. This study identifies critical challenges associated with the last mile segment of postal operations. A qualitative and quantitative survey methodology was employed to evaluate specific public postal service providers within developing nations. These were selected through a stratified sampling method and data were aggregated using a structured questionnaire. Last mile operational models adopted in developed nations were evaluated and identified best practices informed some of the recommendations. The study further considered various environmental impacts of postal operations, and feasible models were explored for integrating into the existing systems.