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This paper examined the nexus between economic growth and exchange rate, remittances, trade, and agricultural output based on data sourced from 1980 to 2018 for 10 selected African economies. We employed both the Dumitrescu and Hurlin time-domain Granger causality test and the Croux and Reusens frequency domain Granger causality test. Results from the time-domain test suggests that causality only exists between economic growth and both exchange rate and trade, with no significant relationship between economic growth and both remittances and agricultural output. When we employed frequency domain model in our analysis, the results suggested that there is a bi-directional temporary and permanent causality between economic growth and exchange rate, trade, agriculture, and remittances. Our results suggest the validity of both the J-Curve and Marshall–Lerner hypotheses in the studied economies. Our study offers some relevant policy implications.

The present study evaluates the influence of kitchen wastes on animal manures via anaerobic digestion for biogas production. The digestion was done using a digester with a capacity of 5L. The digester was loaded with the slurry of wastes prepared by mixing the wastes with water in ratio 1:1, and operated at mesophilic temperature of 37 ± 2°C for 30 days. The co-digestion of kitchen wastes with poultry droppings produced highest biogas yield (814.0 ml/kg VS fed) and the least (365.84 ml/kg VS fed) was from the co-digestion of kitchen wastes with the mixture of poultry droppings and cow dung. Composition analysis of the biogas showed the highest methane content (63.1%) from kitchen wastes and the lowest (56.2%) from co-digestion of kitchen wastes with poultry droppings. The pH range for optimum biogas production varied between 5.25 and 7.5. The study concluded that biogas yield from co-digestion of substrates, among other factors depends on the composition of participating substrates.

Energy recovery and electricity generation from abattoir wastes was investigated with the aim of combating both energy crises and environmental pollution problems. Anaerobic digestion was carried out in a two 10 L batch digesters for about 30 days under mesophilic condition. Biogas volume was measured by water displacement method at every 24 h interval. Based on the volume of biogas produced and its methane composition, electricity value of the produced biogas was estimated. Daily average and cumulative gas volumes of 0.00103 m3/kg VS (1.03 liters) and 0.0309 m3/kg VS (30.90 liters) were obtained respectively with 63.4% methane composition. The results suggest that 1040 MWh and 1664.6 MWh of electricity can be generated from biogas at low-end conversion efficiency of 25% and at high-end conversion efficiency respectively. The study concluded that waste to wealth technology, if appropriately explored is a viable solution to energy crises in Nigeria.

The heating/calorific value of municipal solid waste (MSW) is essential in selecting or designing the appropriate waste to energy (WTE) systems. Experimental evaluation of the heating value of soli...

The study examined the effect oil price long memory and exchange rate long memory on Nigeria's stock. We have used ARMA estimating techniques to assess whether one or both variables exert impact on the stock market in Nigeria. Our result shows that long memory stock price is driven by a long memory of the exchange rate and long stock of the oil price. We therefore recommend that policymakers pursue policies aimed at stabilizing, on the one hand, the exchange rate regime and ensuring the economy has a position in net oil exportations. We also recommend the development of portfolio strategies by market practitioners so that long-term memory in exchange rates as well as in oil pricing are considered when making investment decisions.Keywords: Exchange rate, oil prices, Share prices, long memory, ARMAJEL Classifications: G15, Q43, C58, O40DOI: https://doi.org/10.32479/ijeep.9643

The quest for renewable energy generation is fast increasing globally due to environmental degradation by fossil fuels. The energy production from the anaerobic codigestion of pineapple peels (PPs) and poultry manure (PM) was assessed in the present study. Prior to digestion, the PPs were pretreated using a strong acid (sulfuric acid) and a low‐cost mild alkali hydrogen peroxide (H2O2) which was prepared via the adjustment of the pH of H2O2 to 11.5 by adding solution of 5 M NaOH. The physicochemical and structural parameters of the biomass, as well as microbial composition, were evaluated by using standard methodologies, while all structural changes to the biomass after pretreatment were determined using the Fourier transform infrared spectra. The application of alkaline H2O2 pretreatment removed 71.34% of lignin, reduced hemicellulose by 61%, but increased the cellulose content by 39%. The alkaline pretreated pineapple peel (Al‐P PP) was able to produce about 91% more biogas than the acid pretreated pineapple peel (Ac‐P PP) and 36% more than the two untreated biomass samples. The results of the economic assessment of pretreatment also showed that investment into the use of H2O2 for pretreatment is economically feasible with high net thermal and electrical energy gain, while that of acid pretreatment results in loses. Therefore, alkaline pretreatment application to PPs prior to digestion is hereby solicited in the biotechnological conversion of PPs/wastes for biogas and quality digestate which can be used as biofertilizers or soil enhancers especially in those regions where pineapple production is enormous.

Adsorption of caffeine from an aqueous solution was carried out using Velvet Tamarind-Pericarp, activated with H

In this study, attempt was made to estimate the quantity of municipal solid waste (MSW) generated per annum, the generation rate in kg/capita/day as well as the quantity and the fractions of the waste streams available for energy production. The physical characterization of the waste streams into fractions was conducted. The proximate and ultimate analyses of the waste fractions were performed. Heating values of the waste streams was determined experimentally using a bomb calorimeter. It was concluded that 1% increase in carbon and sulphur will increase heating value by 79.08% and 10.83% respectively while 1% increase in hydrogen and nitrogen decrease heating value by 30.2% and 619.1% respectively. The energy potential (EPMSW) of the MSW based on the energy content of 584 tons/day MSW, is about 3,244,444 kWh or 3,244 MWh, Electrical Power (EPPMSW) of about 40555 kW or 41 MW and Power to Grid of 27 MW. Keywords: Characterization, Energy potential, Generation rate, Heating value, Municipal solid waste, Power potential

In this study, biogas was produced from the anaerobic digestion of Sorghum bicolor stalk. Pretreatment of the biomass was carried out prior to the digestion using sulfuric acid ( H2SO4) and hydrogen peroxide (H2O2). The physicochemical, elemental and structural analyses were carried out on the biomass before and after pretreatment. The microbial composition of the fermenting materials were also determined using standard method while the Fourier Transform Infra-red (FTIR) spectroscopy were used to quantify the structural changes that took place after pretreatments. Results showed enormous reduction of hemicellulose and partial solubilization of cellulose with the application of H2SO4 for pretreatment with obvious breakdown of all important bonds in the biomass. The most suitable condition for the most efficient acidic pretreatment of the Sorghum bicolor stalk was using H2SO4 concentration of 0.75% (v.v−1), autoclave temperature of 118 ◦ C and biomass dry mass of 3.7 g for 52 min. However, the use of H2O2 caused huge solubilization of lignin while partial dissolution of hemicellulose took place. The most suitable condition that gave the best result in this pretreatment procedure was H2O2 concentration of 6.8% (v.v −1), shaker temperature of 28 ◦ C, agitation at 126 rpm and 3 g of biomass for 85 min. Overall, the use of the H2O2 showed reduction of lignin and hemicellulose by 73 and 42% respectively while also increasing the concentration of cellulose by 23%. The acid and alkaline pretreated biomass produced a total of 312.3 and 607.1 LNbiogas.kg VSad −1respectively. In comparison, the biomass pretreated with H2O2 produced 65% more LNbiogas.kg VSad−1 than the other and equally reduced the production time by 5 days. For the alkaline treated biomass, the 1422 kWh t−1 TS thermal energy gain exceeded the 945 kWh t−1 TS used in the pretreatment thus giving a net thermal energy of 477 kWh t−1 TS. However, the acidic pretreatment of Sorghum bicolor stalk is not profitable because the -131 kWh t−1 TS thermal energy gain was far below the 1025 kWh t−1 TS thermal energy used in pretreatment with a net thermal energy of -761 kWh t−1 TS. Till now, use of low-cost H2O2 for biomass pretreatment is unpopular while the uses of other strong alkali and acids are well studies. However, hydrogen peroxide gave better product yield. Therefore, use of this alkali pose a novel biotechnological means for generating biogas. ©2019 The Authors. Published by Elsevier Ltd. This is an open access article under the

This study explored the optimization of pretreatment of pineapple peel for biogas generation. Pretreatments were carried out sulfuric acid and alkaline hydrogen peroxide prior to anaerobic digestion while the response surface methodology (RSM) was used for optimization of the pretreatment procedures. The physical, chemical, proximate and structural compositions of the peels were determined prior to and at the end of the pretreatment procedures. The dynamics of microorganisms in the reactors were also evaluated by rapid molecular methods while the Fourier Transform Infra-red (FTIR) spectroscopy was employed in the identification of the chemical changes as a result of pretreatments. The use of H2O2 pretreatment caused enormous lignin solubilization in the pineapple peel. In comparison, biogas production was 67% more in the alkaline pretreated pineapple peel than the biomass treated with acid and also 51% over the untreated samples. The total biogas volume produced from the acidic pretreated, alkaline pretreated, not sifted untreated and sifted untreated samples are 194.2 ± 3.0, 587.5 ± 5.2, 287.8 ± 2.1 and 245.4 ± 3.1 respectively. Thus, the alkaline pretreated experiment used lower retention time to achieve maximum gas production in this study. The use of alkaline H2O2 on lignocelluloses has remained unpopular prior to this study. However, its usage in this study yielded better result than all the conventional treatments in terms of lignin solubilization and improvement in methane yield. Economically, the use of H2O2 for pretreatment is adjudged feasible because the 1504 kWh t−1 TS thermal energy gain obtained from the biogas produced by the alkaline treated peel exceeded the 921 kWh t−1 TS used in the pretreatment. This gives a net thermal energy of 583 kWh t−1 TS. Whereas, the investment into acidic pretreatment of pineapple peel may not be economically justified because the total thermal energy gain of −200 kWh t−1 TS was far lower than the 1236 kWh t−1 TS thermal energy that was consumed during the pretreatment giving a net thermal energy of −1436 kWh t−1 TS. Therefore, the use of mild alkaline pretreatment is advocated in biogas generation from pineapple peel and also for biofertilizer production mostly in localities of mass production.

In this study, biogas was produced from the anaerobic co-digestion of Cocoa pod husk (CPH) and poultry manure. Pretreatment of the CPH was carried out using sulfuric acid and hydrogen peroxide. The physicochemical, elemental and structural analyses were carried out on the CPH before and after pretreatment. The microbial composition of the fermenting materials were also determined using standard method while the Fourier Transform Infra-red (FTIR) spectroscopy was used to identify the structural changes that took place after pretreatments. Use of alkaline hydrogen peroxide caused high solubilization of the lignin component of the CPH and reduced up to 81% of lignin i.e. initial value of 21.7% m.m-1 to final value of 4.2% m.m-1. Similarly, the alkali reduced the hemicellulose content of the CPH from 27.0% m.m-1 to 8.5% m.m-1. Overall, there was 68% increase in biogas volume from the alkaline pretreated CPH.

This study explored the production of biogas from the mono-fermentation of pretreated Cocoa pod husk. The pretreatment was carried out with sulfuric acid (H2SO4) and alkaline hydrogen peroxide (H2O2) prepared by adjusting the pH of H2O2 to 11.5 by the addition of 5 M NaOH solution. Prior to and after the pretreatments, physicochemical, structural and microbial analyses were carried on the husk using a standard method in each case. In order to determine the changes to the biomass structures after pretreatments, the Fourier Transform Infra-red (FTIR) spectroscopy were used. Average total biogas volume from all the experiments i.e. the acidic pretreated (AcP), alkaline pretreated (AlP), not sifted untreated (NsU) and sifted untreated (SU) was 162.8 ± 5.0, 564.8 ± 5.1, 243.3 ± 4.1 and 220.8 ± 3.3 respectively. This shows that the AlP Cocoa pod husk yielded the highest biogas volume and was followed by the NsU and the SU husk while the lowest was obtained from the AcP biomass. Overall, the AlP biomass produced 71% more total biogas than the AcP one and also produced 57% more biogas than the NsU Cocoa pod husk. The AlP Cocoa pod husk did not only produce the highest biogas volume but also achieved peak of production faster than all the other experimental setups. Total biogas generation was achieved in just 12 days out of the 30-day retention period used in the study in which biogas production started on the 3rd day and climaxed on the 15th experimental day whereas, biogas generation did not commence until after the 5th and 6th days in other experiments and climax was not reached until between the 18th and 21st days. The result of this study has revealed that use of the low cost mild alkali is more efficient in lignin (L) solubilization and subsequent biogas yield improvement. Also, Cocoa pod husk has been shown in this study to be a profound biofuel substrate. Therefore, further use of AlP Cocoa pod husk for biogas and biofertilizer production is hereby advocated especially in major Cocoa producing regions of the world.

The data described in this article was obtained in an experiment designed for the generation of biogas from the anaerobic co-digestion of Telfairia occidentalis (Fluted pumpkin) fruit rind and poultry manure both of which currently constitute an environmental nuisance in the localities where they are found. The data presented in this article is on the use of combined heat and power (CHP) system to assess the energy and economic feasibility of applying thermo-alkali pretreatment procedures to one of the substrates (Fluted pumpkin) prior to anaerobic digestion. Also, the microbial characterization and succession pattern of important microbes during the anaerobic digestion process was evaluated and the data reported in this paper. Keywords: Biogas, Biomass, Economics, Energy, Fluted pumpkin, Microorganisms

The benefits derived from fermented foods and beverages have placed great value on their acceptability worldwide. Food fermentation technologies have been employed for thousands of years and are considered essential processes for the production and preservation of foods, with the critical roles played by the autochthonous fermenting food-grade microorganisms in ensuring food security and safety, increased shelf life, and enhanced livelihoods of many people in Africa, particularly the marginalized and vulnerable groups. Many indigenous fermented foods and beverages of Africa are of plant origin. In this review, the predominance, fermentative activities, and biopreservative role of

In recent times, research attention is focusing on harnessing agricultural wastes for the production of value-added products. In this study, the valorization of Carica papaya (Pawpaw) fruit peels was evaluated for the production of quality organic fertilizer via anaerobic digestion (AD) while the effects of the fertilizer on maize crop were also assessed. Pawpaw peel was first pretreated by thermo-alkaline methods before AD and analyses were carried out using standard methods. The resulting digestate was rich in nutrients and was dewatered to form solid organic fertilizer rich in microbes and soil nutrients. When applied to maize plants, organic fertilizer showed a better effect on plant traits than NPK 15–15–15 fertilizer and without fertilizer application. These were more pronounced at mid to high organic fertilizer applications (30-to-60-kg nitrogen/hectare (kg N/ha)) rate. Comparison between the values obtained from the field experiments reveals that the organic fertilizer showed better performance in all parameters such as the number of leaves, leaf area, plant height, stem girth, total shoot, and root biomass, and length of the root. However, the chemical fertilizer outperformed all the organic fertilizer applied rates in the average highest size of the corn ear by 1.4%. After harvesting, nutrient elements were found to have bioaccumulated in plant organs (leaves, stem, and root) with the highest values being 29.7 mg/L for nitrogen in the leaf and this value was reported from the experiment with 50 kg N/ha. For phosphorus and potassium, the highest concentrations of 7.05 and 8.4 mg/L were recorded in the plant’ stem of the experiment with 50 kg N/ha. All the treated soils recorded an increase in values of all nutrient elements over the control with the highest values recorded in the experiment with 60 kg N/ha. In soil with 60 kg N/ha, the nitrogen, phosphorus, and potassium increased by 28, 40, and 22% respectively over the chemical fertilizer applied experiment while different levels of increases were also recorded for all other macro and microelements in all the experiments. Thus, agricultural practices by using anaerobic digestates as organic fertilizers is a sustainable method to overcome the dependence on inorganic fertilizers high rate.

Vinasse is a highly polluting by-product waste from bioethanol production processes. In this work, the biochemical methane potential (BMP), biodegradability index (BI), competitiveness index (CI) and physicochemical properties of cassava vinasse (CV) obtained from an ethanol distillery were studied to gain a better understanding of its characteristics and suggest alternative treatment routes and usage. At 28 o C, the CV used had a moisture content, specific gravity, refractive index and Brix value of 93%, 1.03, 1.34 and 5.88% sucrose, respectively. It exhibited relatively high Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) of 62000-736500 and 21620-25000 mg/L, respectively. These, coupled with its acidic pH of 4.2–4.8 and cyanuric acid content of 386–450 mg/L, emphasized its potential as a pollutant both on land and water. The high volatile solids content of 71580-72250 mg/L and BOD-to-COD ratio of 0.3:1–0.4:1 both point to the presence of biodegradable organic matter. The CV contained macro and micro-nutrients in addition to salts of phosphates, nitrates and sulphates. At standard temperature and pressure, a BMP of 247.10 NmL/gVS points to the potential of the CV as a bioenergy resource. Also, while a BI of 0.82 indicated that 82% of organic matter in CV is degradable, a CI above 10 means no competition between the methanogens and the sulphate-reducing bacteria (SRB) if the CV is subjected to anaerobic digestion (AD). Based on these results, the CV could be treated via AD with simultaneous biogas production and, to some extent, used as a nutrient source for microbial-driven bioprocesses.

Adsorption of caffeine from an aqueous solution was carried out using Velvet Tamarind-Pericarp, activated with H3PO4. The adsorbent was characterized using a scanning-electron microscope and the Brunauer-Emmett-Teller. Parameters such as activating agent concentration (80 wt.% in 100 mL solution), initial caffeine concentration of 5���40 g/L, pH of 0���14, and residence time 0���90 minutes, were investigated. Improved adsorptive capacities were seen at increased acid concentrations, with the highest removal rate obtained at a pH of 6. The highest residence time and adsorbent concentrations were obtained at 40 min and 10 g/L. The surface adsorption of the adsorbent obeyed the Langmuir Isotherm, while the regression coefficients conformed to the pseudo-second-order kinetic model for the remediation of caffeine with DG-AC. The highest amount of caffeine removed per gram DG is 72.60 mg.g���1. From the thermodynamic study, the caffeine adsorption was feasible, spontaneous, entropy-driven, and endothermic. These data show that the use of DG-AC can be a good alternative to other expensive methods for caffeine remediation. The Pseudo ��� first/second-order kinetic results gave R2 values of 0.95 and 0.99, other parameters such as entropy (��S��) and enthalpy (��H��) are 0.06 (kJmolK) and (19.21) (kJmolK). Novelty statement The novelty of the work is that the adsorption of caffeine from an aqueous solution/pharmaceutical wastewater was carried out on activated carbon produced from African velvet tamarind (pericarp) and phosphoric acid as activating agent.

Anaerobic digestion (AD) is a biological process that converts complex substrates into biogas and digestate under microbial activity in the absence of oxygen through four main steps: hydrolysis, acidogenesis, acetogenesis, and methanogenesis. It is one of the well-studied technologies for stabilizing organic wastes. Among the treatment technologies available for organic solid wastes, AD is quite suitable because of its environmental friendliness and high potential for energy recovery and production of quality and nutrient-rich digestates, which can in turn be processed to biofertilizers. Such positive aspects coupled with recent concerns about rapid population growth, increasing food demand, and global warming have promoted further research on the biofertilizer production process development and improvement in order to enhance the quality of biofertilizers and by extension enhance their abilities to influence crop growth and well-being and soil nutrient improvement. AD is equally known to be famous in both developed and developing countries where mostly the produced gas is used as fuel for cooking and other purposes while the digestate is used as fertilizers or soil conditioners. However, agronomic characteristics of digestates can produce harmful effects due to digestate quality in terms of pH, organic matter imbalance, and especially heavy metal content. There is therefore the need to evaluate the differences and similarities in agronomic characteristics and the values of anaerobic digestates taking cognizance of their production materials, type of biogas plant that treated it, and the prevailing environmental factors. It is important to study the chemical analyses and the availability of nutrients before applying biofertilizers. Also, crop growth and soil mineralization experiments with biofertilizers should be controlled. Lastly, lifecycle assessments must be carried out with a circular economy approach.

Malaria and Neglected Tropical Diseases (NTDs) are highly endemic in poorer countries of the world. The research investigated the prevalence of parasitic infections among children in Internally Displaced Persons (IDP) camp in Benin City. Faecal, urine and blood specimen were collected from 184 children (100 males and 84 females) aged 6–15. Blood samples were prepared using thick film method and analyzed microscopically. Direct smear technique was employed for faecal sample and sedimentation method to concentrate ova from the urine sample. Ten species of parasites were identified in this study. The predominant species were Plasmodium falciparum (67.93%), Entamoeba histolytica (67.93%) and Giardia duodenalis (59.78%). Plasmodium falciparum and E. histolytica were most prevalent in both sexes, with P. falciparum infecting 68% males and 67.86% females while E. histolytica infected 66% males and 70.24% females (P = 0.24). Mixed infections with blood and intestinal parasites were recorded in 41.18% in age group 5–10 and 47.90% in age group 11–15 (P < 0.5). Also, mixed infections with blood and intestinal parasites were detected in 45% males and 50% females (P = 0.51). Urinary schistosomiasis was recorded in 28.80% of the participants. Parasitic infections especially P. falciparum malaria and amoebiasis were predominant among the children. Therefore, our findings call for specific intervention programmes to reduce parasite intensity and morbidity in the children. Environmental and personal hygiene should be implemented in order to curb parasitosis in the study area., Zoology; Public health; Infectious disease; Prevalence; Plasmodium falciparum; Entamoeba histolytica; Polyparasitism; Hygiene.

A biochemical system was used for electricity generation from food waste (FW) and spent animal beddings (SAB). The wastes were blended and fermented anaerobically to produce fermentation liquids used as fuels for running a catalytic fuel cell. The fermentation liquids were analyzed for their components. The results show the organic contents i.e. volatile solids of both FW and SAB to be 23.4 and 20.9 g/L while the carbon contents were 6.5 and 6.1 g/L respectively. The media were however very rich in volatile fatty acids (VFAs). When used, the fermentation liquids from FW and SAB generated mean open-circuit voltages of 0.64 and 0.53 V and mean maximum power densities (Pmean) of 1.6 and 1.3 mW/cm2 respectively. The fuel cell showed very high efficiency in the conversion of all VFAs especially butyric acid with the highest been 97% for FW and 96% for SAB.

Field experiments were carried out in 2018 and 2019 cropping seasons at Landmark University Teaching and Research farm, Omu-Aran Kwara state, Nigeria, to determine the effect of soil applied Zn-fertilizer, Tithonia diversifolia (Ti), Chromolaena odorata (Ch) and poultry manure (PM) on the performance, yield, minerals and vitamins composition of okra fruits. Treatments were combined and tested as follows:—Control (T1), Control + 10 kg ha−1 Zn (T2), 5 t ha−1 Ti + 5 t ha−1 PM (T3), 5 t ha−1 Ch + 5 t ha−1 PM (T4), 5 t ha−1 Ch + 5 t ha−1 Ti (T5), 10 t ha−1 Ti + 0 kg ha−1 Zn (T6), 10 t ha−1 Ti + 10 kg ha−1 Zn (T7), 10 t ha−1 Ch + 0 kg ha−1 Zn (T8), 10 t ha−1 Ch + 10 kg ha−1 Zn (T9), 10 t ha−1 PM + 0 kg ha−1 Zn (T10), and 10 t ha−1 PM + 10 kg ha−1 Zn (T11). The experiment was laid out in a randomized complete block design with four repetitions. Vegetative, yield and quality parameters of okra were taken. Data were subjected to analysis of variance and means were compared using Duncan Multiple Range Test (DMRT) at p ≤ 0.05. Variations were observed on the vegetative parameters, yield, minerals and vitamin composition of okra among the applied amendments. The combined application of green biomass, poultry manure, and Zn-fertilizer improved all the variables tested as compared to when they were applied singly. Application of Zn-fertilizer to some selected plots significantly increased yield, Zn, Mg and vitamins concentration of okra. Application of 5 t ha−1 Ti + 5 t ha−1 PM + 10 kg ha−1 Zn (T3) and 5 t ha−1 Ch + 5 t ha−1 PM + 10 kg ha−1 Zn (T4) significantly improved all the parameters tested but the use of 5 t ha−1 Ti + 5 t ha−1 PM + 10 kg ha−1 Zn (T3) resulted in optimum yield and at the same time increase minerals and vitamin concentration of okra. The results of this study therefore showed that Tithonia diversifolia (Ti) as green biomass contained and released more and quality nutrients than Chromolaena odorata (Ch) when combined with equal rate of Zn fertilizer and poultry manure.

The study investigated bioenergy generation from anaerobic co-digestion of food wastes (FW), cow dung (CD) and piggery dung (PD). The physicochemical parameters of the substrates were determined before and after digestion following standard procedures after mechanical pretreatment. Throughout the study, pH remained slightly alkaline while temperature varied between 26 and 32 °C. The highest cumulative biogas yield of 0.0488 L was recorded from the digestion of FW + CD + PD on the ninth day. After analyses, the highest methane content of 64.6 was obtained from the digestion of FW + PD while the lowest (54.0%) was from the digestion of FW only. Overall, cumulative biogas production for the four digestion regimes followed the order: FW + CD + PD, FW + PD, FW + CD and FW only respectively. Accumulation of VFAs was recorded at a slow rate during the digestions.

This research investigated the use of cow dung (CD), poultry dung (PD) and cow dung/poultry dung for the bioremediation of artificially contaminated soil with petrol using response surface methodology. The application of cow dung and poultry dung to the contaminated soil was done through a statistical approach and the Box–Behnken design of experiment was adopted using design expert 6.0.8 software. The percentage of petrol removed was used as the response to assess the biodegradation. Experimental results revealed 84–96% for petrol degraded. Analysis of results showed that the quadratic model fitted best with R2 value of 95.85% of petrol removed and the results were also significant at probability values of 0.0487, 0.0114, 0.0113, 0.0001, 0.0016, 0.0234 and 0.003, respectively, were less than 0.05. The optimum process conditions obtained were 2.54 g CD, 3.34 g PD and 2.41 g CD/PD for the percentage of petrol removed and it gave a percentage of petrol removed as 99% from day 5 and then attained equilibrium. A graph of days vs percentage of petrol removed was plotted. Furthermore, biochemical test was carried out on the soil and three of the microorganisms were used also for the bioremediation. The microorganisms are Bacillus, Aspergillus and E. coli, respectively. The best degrader of petrol from the microorganism was Bacillus in which the percentage of petrol removed was 92%. This indicates that augmenting artificially contaminated soil with petrol with cow dung and poultry dung will enhance remediation and restoration of the polluted soil.

This study evaluated the anaerobic mono-digestion of two different samples of Chromolaena odorata. Combinations of mechanical and thermo-alkaline pretreatments were applied to one of the two samples and labeled as “X” while the second had no thermo-alkaline treatment and was labeled as “Y”. The Central Composite Design was used to design the pretreatments. The physicochemical characteristics of the substrates were carried out using standard methods after appropriate pretreatments. From the experimental set-ups, the most probable actual biogas yields in experiments “X” and ”Y” were 0.3554 m3/kg Total Solid (TS)fed and 0.1803 m3/kg TSfed with the desirability of 99 and 100%, respectively. Further shown in the result is a 49.2% higher experimental (actual) biogas yield in experiment “X” over “Y”. Gas chromatographic analysis revealed the CH4 and CO2 content of both experiments to be 65 ± 1.5%; 21 ± 3% and 53.5 ± 2.5%; 26 ± 3%, respectively. Combination of different pretreatment methods enhanced enormous biogas yield from the digested substrates. Optimization of the generated biogas data was carried out using the Response Surface Methodology (RSM) and the Artificial Neural Networks (ANNs). The coefficient of determination (R2) for RSM was lower compared to that of ANN. This shows that ANNs model gives higher accuracy than RSM model. Further utilization of this weed for biogas production is encouraged by the results from this study. Keywords: Anaerobic digestion, Lignocellulosic biomass, Methane, Optimization, Pretreatment, Siam weed

This study was aimed at establishing a water quality database in the study area where none existed previously. Samples were taken from two different sites of River Oluwa, South-Western Nigeria. Physicochemical and biological factors and the metals for one year (April 2011–March 2012) were evaluated using standard methods. All the physical parameters of the water samples from the two sampling Sites did not show deviations from Nigeria Industrial Standard (NIS) for permissible levels of these parameters in drinking water. Virtually all heavy metals investigated deviated from the permissible levels allowed by NIS, and WHO standards in drinking water. In the same vein, all chemical parameters investigated during the dry season was significantly different from rainy season except for BOD at P < 0.05. Isolated microorganisms include members of the genera Bacillus, Micrococcus, Pseudomonas, Streptococcus, Proteus and Staphylococcus. The public health implications of consuming water from this river are fully discussed. Keywords: Bitumen, Drinking water, Health, Nigeria, Pollution, Standards

This study investigated the biogas production potential of Pennisetum purpureum (Elephant grass) (El-g) co-digested with piggery manure (PM) under mesophilic condition in order to combat the menace of weed in cropping systems as well as pollution problems emanating from disposal of PM. Prior to anaerobic digestion (AD), El-g was subjected to a combination of mechanical, thermal and alkaline pretreatments. Using cattle rumen content as inoculum, the pretreated El-g was anaerobically co-digested with PM while the raw El-g was also co-digested with PM and served as control experiment. The physicochemical characteristics of feedstock were evaluated before and after the digestion period using standard methods. The initial high concentrations of chemical oxygen demand (COD) reduced significantly after digestion indicating efficiency of the digestion process. Also, there were reductions in concentrations of calcium and other parameter needed for microbial growth after the digestion which indicated their utilization by microbes to generate biogas. Biogas production began on the 5th and 7th days and was progressive until 30th and 24th days in both digestions after which a decline was observed until the end of the experiment. For the digestion period of 37 days, the total biogas recorded from the pretreated and untreated experiments were 409.5 and 184.1 m3 CH4/kg VS with average of 11.07 and 4.98 m3 CH4/kg VS/day respectively. The study concluded that co-digestion with piggery dung enhanced the biogas producing capacity of El-g hence advocated.

In this study, the potentials of pretreated and untreated Carica papayas fruit peels for biogas generation was evaluated alongside its process optimization after employing the combination of mechanical and thermo-alkaline pretreatment methods. The peel was anaerobically digested using a consortium of microorganisms from cattle rumen content as inoculum. A batch system designed by the Central Composite Design (CCD) was employed. The physicochemical and microbial characteristics of the substrates and inoculum as well as the constituent of the generated biogas were evaluated using standard methods and results showed elevated levels of most elements after anaerobic digestion. The most feasible experimental biogas yields were 0.1839 m3/kg VS and 0.1361 m3/kg VS for the pretreated and untreated experiments respectively. Microbiologically, members of the genus Clostridium dominated the microbial flora and their succession patterns were affected by temperature and pH. The methane and carbon dioxide content of biogas from both experiments were 61.5± 2.5%; 24± 1% and 52 ± 2%; 25± 1.5% respectively. The Response Surface Methodology (RSM) and the Artificial Neural Networks (ANNs) were employed in data optimization. Based on the optimized values, the predicted biogas yield for RSM was 0.1895 m3/kg VS and 0.1839 m3/kg VS for ANNs in the pretreated experiment. For the experiment without pretreatment, the RSM predicted yield was 0.1361 m3/kg VS while that of ANNs was 0.1392 m3/kg VS. In all, there was a 26.5% increase in predicted biogas yield in the pretreated experiment over the untreated. Further usage of pawpaw peels for biofuels generation is advocated.

The potential of a major bioresource (Peanut hull) for biogas generation was evaluated. A sample was pretreated using combinations of mechanical and thermo-alkaline procedures using the Central Composite Design (CCD) for the optimization of the pretreatment temperature and time while another sample was treated without thermo-alkaline methods. The physico-chemical and microbial characteristics of the A. hypogaea hull and the rumen contents were carried out using standard methods. The actual biogas yields were 1739.20 m3/kg TSfed and 1100.50 m3/kg TSfed with desirability values of 91 and 100% for the pretreated and untreated experiments respectively. The methane and carbon dioxide content of biogas from both experiments as revealed by Gas chromatography were 61.5 ± 2.5%; 24 ± 1% and 51 ± 2%; 25 ± 2% respectively. The optimization of important process parameters in the anaerobic digestion were done using CCD of Response Surface Methodology (RSM) and the Artificial Neural Networks (ANNs) and the optimal values for each of the five major parameters optimized are as follows: Temperature = 30.00 �C, pH = 7.50, Retention time = 30.00 day, Total solids = 12.00 g/kg and Volatile solids = 4.00 g/kg. Taking these values into account, the predicted biogas yield for RSM was 1819.89 m3/kg TSfed and 1743.6 m3/kg TSfed for ANNs in the thermo-alkaline pretreated experiment. For the experiment without pretreatment, the RSM predicted yield was 1119.54 m3/kg TSfed while that of ANNs was 1103.40 m3/kg TSfed. In all there was a 38.5% increase in predicted biogas yield in the experiment with pretreatment over that of untreated A. hypogaea hull. Based on the coefficient of determination (R2), the mean error and predicted biogas yields, ANNs was found more accurate and is recommended for the optimization of biogas generation from the substrate used in this study. Further usage of peanut hull for biofuels is encouraged.

Anaerobic co-digestion of pretreated and untreated samples of Tithonia diversifolia with poultry droppings was carried out to establish a permanent solution to the menace of this stubborn weed present in crops worldwide. The physicochemical and microbial characteristics of the substrates (T. diversifolia, poultry droppings, and rumen contents) were evaluated using standard methods. The initial high chemical oxygen demand (COD) values were significantly reduced by 60.45 and 56.33% after digestion. In all the experiments, biogas production was progressive until between the 16th and 21st days in most cases, after which a decrease was observed until the end of the experiments. The most desirable actual/experimental biogas yields from both experiments were 2984.20 and 1408.02 m3/kg total solids (TS) fed, with desirability of 100% for both experiments. Gas chromatographic analysis revealed the CH4 and CO2 contents of both experiments to be 67 ± 1.5%; 22 ± 2% and 60 ± 1%; 23 ± 2%, respectively. The response surf...

Fish may harbor pathogens on or inside its body when in contaminated environment. Clarias gariepinus and Clarias buthopogon were analyzed to evaluate the likely impact of pollution on the antidrug resistance pattern of their microbial isolates. Different bacterial and fungal counts were observed on the fish organs (skin, muscles and gills). The highest bacterial count was 1,040,000 Cfu/mL while the lowest was 101 Cfu/mL. The highest fungal count obtained was 344,000 Cfu/mL while the lowest was 65 Cfu/mL. Bacterial isolates belonging to genera Bacillus , Clostridium , Alcaligenes , Flavobacterium , Enterobacter and Corynebacterium were obtained from the organs . Also, fungal isolates belonging to the genera Penicillium , Aspergillus , Rhizopus , Monila and Fusarium were isolated. The resistance of isolates from C. gariepinus to drugs was between 50% and 90% with Bacillus species showing the highest resistance. For isolates from C. buthopogon , 40–90% resistance was observed with Alcaligenes faecalis showing highest resistance. Five patterns of multiple drug resistance were observed among the bacterial isolates with antibiotics ranging from 4 to 9. Also, result of fungal isolates showed susceptibility to ketoconazole and resistant to fluconazole and griseofulvin. The public health implications of consuming these fishes are discussed.

Aims Plant extracts have long been used for the ethnomedical treatment of diabetes, microbial infections and as a source of antioxidant. This study was aimed at investigating the antidiabetic, antioxidant, and antimicrobial activities of the n-hexane and ethyl acetate extract of Tephrosia bracteolata leaves (TBL) as associated with the ethnobotanical knowledge of the local people of Nigeria. Main methods The phytochemical composition of the n-hexane and ethyl acetate extract of the leaves of T. bracteolata were determined following standard procedures in literature, and it's in vitro inhibitory activities against α-glucosidase enzyme. 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS.+) and 1,1-diphenyl-2-picrylhydrazyl (DPPH+) antioxidant activities were also examined. Well diffusion method was employed in evaluating the antimicrobial property of the extracts. Key findings The ethyl acetate extract of T. bracteolata leaves had the greatest inhibitory effect on α-glucosidase, followed by the n-hexane with IC50 43.95 μg/ml and IC50 ˃50 μg/ml respectively. The ethyl acetate also exhibited significant DPPH+ and ABTS.+ antioxidant activity with IC50 of 24.96 μg/ml and 6.48 μg/ml as compared to Ascorbic acid and Trolox (12.24 μg/ml and 5.91 μg/ml) respectively. The zones of inhibition of the ethyl acetate extract of T. bracteolata leaves ranges from 10 – 25 mm at a concentration of 6.25–200 mg/ml, and it showed a greater antibacterial activity than the n-hexane extract, having a zone of inhibition from 10 – 20 mm at concentration of 12.5–200 mg/ml when compared to the standard Gentamycin. Similarly, the ethyl acetate extract of T. bracteolata showed a better anti fungi activity at concentration range 12.5–200 mg/ml than the n-hexane extract at concentration range of 25–200 mg/ml with reference to Tioconazole. These results indicated for the first time that the ethyl acetate extract of T. bracteolata leaves extracts exerted potent inhibitory effects against α-glucosidase, actively scavenge DPPH+ and ABTS.+ free radicals and successfully inhibits the proliferation of Gram positive and Gram negative microorganism. Significance TBL is an important source of antidiabetic, antimicrobial and antioxidant agent.

The study evaluated anaerobic co-digestion of poultry dropping and pawpaw peels and the optimization of important process parameters. The physic-chemical analyses of the substrates were done using standard methods after application of mechanical, thermal and chemical pre-treatments methods. Gas chromatography analysis revealed the gas composition to be within the range of 66-68% methane and 18-23% carbon dioxide. The study equally revealed that combination of the different pre-treatment methods enhanced enormous biogas yield from the digestion. Optimization of the generated biogas data were carried out using the Response Surface Methodology and the Artificial Neural Networks. The coefficient of determination (R(2)) for RSM (0.9181) was lower compare to that of ANN (0.9828). This shows that ANN model gives higher accuracy than RSM model for the current. Further usage of Carica papaya peels for biogas generation is advocated.

Municipal Solid Waste (MSW) streams of Ilorin was characterized for four months in each season: May to August 2016, representing wet season; and November 2016 to February 2017 representing dry season. Thirty-two samples of 240 L bin volume of MSW were collected randomly, from heaps of wastes at Lasoju/ Eyenkorin for each season. The samples were manually sorted on the metallic (screening) table (1.5 m × 3 m with 10 mm × 10 mm surface mesh). Nine combustible waste fractions, out of the nineteen waste components characterized, were considered for laboratory analysis. Proximate analysis revealed averages of 57% and 55% fixed carbon content for wet and dry seasons respectively. Ultimate analysis gave 29 and 29.2% total carbon content for wet and dry seasons respectively. Models were developed to ascertain the correlation between the physicochemical properties and the heating values of the waste fractions. The MSW predicted for the dry season was 158 tons/day, with generation rate of 0.15 kg/capita/person, heating value of 29 MJ/kg, energy and power potentials of 890.2 M W h and 11.27 MW, respectively. MSW for wet season was 210 tons/day, with 0.02 kg/capita/day, heating value of 26 MJ/kg, energy and power potentials of 1.1 G W h and 1.06 GW, respectively.

In developing countries, the continuous need to increase meat production for the growing population has resulted in upsurge in the number of abattoirs or slaughterhouses within their major cities. Most of these abattoirs release huge amount of wastewater to the environment with little or no concern for resultant health effects. In this study, anaerobic digestion for biological treatment of abattoir waste in a batch reactor system was investigated. Correlation parameters that relate average gas production rate and working volume of digester were also developed. Abattoir wastewater was anaerobically digested for 30 d. During the period, the pH, temperature, chemical oxygen demand (COD), total solid (TS), and total volatile solid (TVS) were determined every 24 h. In 30 d, 30.9 L of biogas was produced with average daily yield of 1.03 L. A total of 84.1% of COD, 83% of TVS and 77% of TS were removed after the digestion period. These parameters were used to develop correlations between the average gas production rate and working volume of digester based on reduced COD, TVS and TS; and this was found to be in good agreement with the obtained experimental results.

One of the major indicators of social and economic development of a nation is energy. The global development in energy production has so grown that there are currently less than a billion people without access to electricity. However, Africa has again been left out of this mundane progress while Asia with about the same energy dilemma was able to provide electric energy to 375 million of its citizenry between 2011 and 2017. Meanwhile, India, Bangladesh, and Indonesia were all able to provide over 80% electrification rates to their teeming population. Though some levels of improvement have been witnessed in Africa’s electrification projects up to about 43%, the slow pace of development in comparison with other parts of the globe is very worrisome especially due to the ever-increasing human population being witnessed across the African continent. This explains why yet over 600 million African are still living without access to electricity. Therefore, this paper examines the past and current status of bioenergy development across Africa while advocating for the inclusion of bioenergy in the African future energy projection due to their immense potentials to transform the continent. Africa stands a chance of becoming a major player in the global energy market.