scispace - formally typeset
Search or ask a question
Author

A. O Onokwai

Other affiliations: Bells University of Technology
Bio: A. O Onokwai is an academic researcher from Landmark University. The author has contributed to research in topics: Biogas & Renewable energy. The author has an hindex of 6, co-authored 18 publications receiving 106 citations. Previous affiliations of A. O Onokwai include Bells University of Technology.

Papers
More filters
Journal ArticleDOI
TL;DR: In this article, a comparative analysis of the rates of production of biogas from various organic wastes and weeds was carried out, which enabled the determination of optimal ratio of poultry droppings to domestic wastes.
Abstract: This study carried out a comparative analysis of the rates of production of biogas from various organic wastes and weeds which enabled the determination of optimal ratio of poultry droppings to domestic wastes. Digester was prepared for the anaerobic fermentation of the domestic wastes and weeds. The gas production did not begin until the 7th day and increased steadily at first, and then increased sharply until it reached its peak on the 18th day before declining. The total gas produced within the 22 days of experimentation was 1771 cm 3 . The maximum volume of gas amounting to 809 cm 3 was produced by the sample containing 50% poultry dropping and 50% weeds. This indicates that this sample possesses the best C/N ratio of all the samples prepared. For restarted digester, gas production began on the 2nd day as against the 7th day with no restarted digester and the gas production peaked earlier.

46 citations

Journal ArticleDOI
TL;DR: A parabolic solar cooker was designed and constructed to serve as an alternate renewable source of energy for cooking and to also reduce the adverse effects of other sources of energy on the environment as discussed by the authors.

30 citations

Journal ArticleDOI
01 Oct 2021
TL;DR: In this paper, the authors used the modified Gompertz model to predict the relevant kinetic variables of the digestion process and found that increase in the amount of cow dung beyond 25% led to decrease in biogas yield.
Abstract: In this study, investigation was done to determine the optimum combination of cow dung (CD) and horse dung (HD) for enhanced biogas production and plant stability. Anaerobic co-digestion of CD and HD at varying percentage combination was carried out in five (5) identical 25 L cylindrical digesters (A–E) for a retention period of 37 days, at an average ambient temperature of 33 °C. Using the Microsoft excel solver function, 2010 version, the modified Gompertz model was applied to predict the relevant kinetic variables of the digestion process. Result obtained shows that digester D with 25% CD and 75% HD produced the highest daily biogas, followed by C (50% CD and 50% HD), B (75% CD–25% HD), A (100% CD) and E (100% HD). Digester D also had maximum biogas production potential (A) of 13.8 L/gVS, maximum biogas production rate (µ) of 0.69 L/gVS/day and shortest lag phase (λ) of 5.20 days. Digester E with 100% HD, though had a short lag phase of 5.72 days, had the least total biogas yield of 5.1 L/gVS. The closeness of the coefficients of determination (R2) to 1 reflects a good fit, between experimental and simulated data. The study found that increase in the amount of cow dung beyond 25% led to decrease in biogas yield. It has also shown that biogas production from CD and HD is feasible and can serve as way of removing CD and HD from the environment while serving as a source of bioenergy. Further study on best ways of pre-treating the substrates for greater biogas yield is recommended.

19 citations

Journal ArticleDOI
TL;DR: In this paper, a research was performed to optimize the performance characteristics of the Nigerian Jebba Hydropower Plant in order to enhance its generation of electricity, and the performance of the Jebba hydropower plant was analyzed.
Abstract: This research was performed to optimize the performance characteristics of the Nigerian Jebba Hydropower Plant in order to enhance its generation of electricity. Pertinent hydropower data were hour...

16 citations

Journal ArticleDOI
TL;DR: The study concluded that that CF without chemical and or enzymatic pre-treatment was not a good co-substrate of HD for enhanced biogas production.
Abstract: This study examined the effect of the anaerobic co-digestion of chicken feather (CF) and horse dung (HD) on biogas production and yield kinetics. It was carried out in eight (8) experimental designs using eight (8) identical digesters with replication. While Digesters A and B contained 100 % HD (6 kg) and 100 % CF (6 kg) respectively, C, D and E contained 75 % HD, 50 % HD and 25 % HD (4.5 kg, 3 kg and 1.5 kg) respectively. The last three Digesters F, G and H contained 75 % HD: 25 % CF, 50 % HD: 50 % CF and 25 % HD: 75 % CF respectively. Average biogas production for digesters with 100 % HD, 100 % CF, 75 % HD: 25 % CF, 75 % HD: 50 % HD: 50 % CF, 50 % HD and 25 % HD: 75 % CF are 0.36, 8.22876E-04, 0.20, 0.27, 0.14, 0.18, 0.097 and 0.09 L/gVS respectively. The paired t-test result showed a significant difference for 75 % HD and 50 % HD when co-digested with CF but no significant difference for 25 % HD at 95 % confidence level. The modified Gompertz model revealed that chicken feather had negative effects of 6.89 %, 14.84 % and 27.75 % on total biogas produced, maximum specific biogas yield (μm) and latency (λ) respectively. The study concluded that that CF without chemical and or enzymatic pre-treatment was not a good co-substrate of HD for enhanced biogas production.

15 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: In this paper, a small-scale production of biogas was undertaken using spent mushroom compost (SMC), and the carbon to nitrogen (C/N) ratio, temperature of the reactor (T), and retention time (RT) were the independent variables of the study.
Abstract: In this study, a small-scale production of biogas was undertaken using spent mushroom compost (SMC). The carbon to nitrogen (C/N) ratio, temperature of the reactor (T), and retention time (RT) were the independent variables of the study. Maximum production of biogas is related to the C/N ratio of 20 at temperature of 35 °C (cumulative values of 40.5183 ml/g of VS) and C/N ratio of 30 at temperature of 55 °C (cumulative value of 44.1001 ml/g of VS). Logistic, ANFIS, and ANN models were employed in modeling the production process of biogas. Comparing the values of the results indicate that the total values of RMSE and r in case of mesophilic temperature (35 (°C)) for ANFIS network are 0.1940 and 0.9998, for MLP network are 0.780 and 0.9981, and for logistic model are 0.5111 and 0.9992, respectively. And also at the thermophilic temperature (55 (°C)), the total values of RMSE and R were calculated as 0.3033 and 0.9997 for ANFIS network, 0.3430 and 0.9992 for MLP network, and 0.5506 and 0.9991 for the logistic model, respectively. Therefore, it can be reported that the ANFIS network accurately predicted the output values of the both thermophilic and mesophilic situations.

91 citations

Journal ArticleDOI
TL;DR: Tangerine, pomegranate and banana peels valorisation methods are described, revealing different uses and Physicochemical and microbiological characteristics of tangerines, pembrokeshire and Banana peels.

64 citations

Journal ArticleDOI
TL;DR: In this paper, the authors discuss the potential of palm oil and its residues in the energy and transportation sector, including its potential as transportation fuels, and discuss the future challenges of the palm oil industry.
Abstract: The importance of energy demands that have increased exponentially over the past century has led to the sourcing of other ideal power solutions as the potential replacement alternative to the conventional fossil fuel. However, the utilisation of fossil fuel has created severe environmental issues. The identification of other renewable sources is beneficial to replace the energy utilisation globally. Biomass is a highly favourable sustainable alternative to renewable resources that can produce cleaner, cheaper, and readily available energy sources in the future. The palm oil industry is essentially ideal for the availability of abundant biomass resources, where the multifaceted residues are vital for energy production through the conversion of biomass waste into value-added products simultaneously. This article discusses the utilisation of palm oil and its residues in the energy and transportation sector. Assessment and evaluation on the feasibility of palm oil and its residues were made on the current valorisation methods such as thermochemical and biochemical techniques. Their potential as transportation fuels were concurrently reviewed. This is followed by a discussion on future challenges of palm oil industries that will take place globally, including the prospects from government and nongovernment organisations for the development of palm oil as a sustainable alternative replacement to fossil fuel. Hence, this review aims to provide further insight into the possibilities of palm oil and its residues towards sustainable development with reduced environmental-related issues.

50 citations

Journal ArticleDOI
TL;DR: In this article, the performance of an Indirect Solar Dryer (ISD) with three different cases, namely solar collector - without thermal energy storage (TES), with TES unit having Phase Change Material (PCM) and with TEs having fins inserted PCM have been experimentally analyzed during spring and summer seasons for drying Momordica charantia.

41 citations

Journal ArticleDOI
TL;DR: In this article, two similar storage cooking pots are experimentally evaluated and compared during solar cooking and storage off-sunshine cooking periods, and the results show that the sunflower oil cooking pot shows better performance during the solar cooking periods since it shows shorter cooking times (1.8-5.6h) compared to the erythritol-based phase change material (PCM) pot (3.8−6.6 h).

31 citations