Elijah T. Iyagba

Bio: Elijah T. Iyagba is an academic researcher from University of Port Harcourt. The author has contributed to research in topics: Reaction intermediate & Freundlich equation. The author has an hindex of 6, co-authored 6 publications receiving 215 citations. Previous affiliations of Elijah T. Iyagba include University of Pittsburgh.

The study of cow dung as co-substrate with rice husk in biogas production

Abstract: The co-digestion of cow dung with rice husk for biogas production at laboratory scale was the subject of this investigation. The study was carried out at room temperature that is, 26 - 29°C for a period of 52 days with a total solid concentration of 8% in each sample (fermentation slurry). The biogas produced was collected by water displacement method which was subsequently measured. Sample A (50 wt % cow dung, 50 wt % rice husk) showed a cumulative biogas production of 161.5 ml at the end of the 38th day of the experiment after which there was no further production. The production from sample B (25 wt % cow dung, 75 wt % rice husk) was not significant, while there was no production from sample C(0 wt % cow dung, 100 wt % rice husk). Key words: Biogas, cow dung, rice husk, co-digestion.

Solid Soap Production using Plantain Peel Ash as Source of Alkali

Abstract: The making of soap using vegetable matter (plantain peel) ashes was examined. All the factors that could cause blackness in the colour of the soap, when the water extract of ashes derived from vegetable matter was reacted with palm oil/palm kernel oil blend, were studied with a view to remedying them. These remedial procedures included a clearer filtration in the extraction stage, which removed virtually all black particles from the extract; elimination of any metallic ions in the ash extract, which could colour the resulting soap, and bleaching of the oil blend. The saponification stage of the soap making process was also changed from those of previous practices since some of the previous saponification processes led to charring of the soap and hence caused it to be black. A neat soap, which was milky white in colour, was obtained when the improved ash extract was reacted with the bleached oil blend. This was also the colour of two other soaps made from pure potassium hydroxide and pure sodium hydroxide alkalis, respectively and the same bleached oil blend. It was concluded that solid soap, which was not black, could be made from ash-derived alkali. This is the first reported case of such an attempt. (Journal of Applied Sciences & Environmental Management: 2002 6(1): 73-77)

Development of Mathematical Models and Application of the Modified Gompertz Model for Designing Batch Biogas Reactors

Abstract: Biogas is a combustible gas produced by the anaerobic digestion of organic matter (biomass) in the absence of oxygen. In this study, mathematical models for the design of batch anaerobic biogas reactors for digesting cattle dungs at ambient temperatures (30 ± 3 °C) were developed. Biogas productions from five (5) reactors with varying mass of total solids were monitored for a period of 42 days. It was observed that optimal biogas yield (y t ) occurred at volatile solids concentration in the range of 60.0–80.0 g VS/L, which corresponds to 8.0–10.0 % total solids. Optimum biogas yield rates were between 1.44 and 1.64 ml/g VS/day. The modified Gompertz model was used in predicting maximum biogas yield (y m ), maximum biogas yield rate (R m ), the minimum time taken to produce biogas (λ), and these were found respectively to be between 68 and 86 ml/g VSloaded, 2.50–2.97 ml/g VSloaded/day and 9.7–12.0 days with goodness of fit ranging from 0.996 to 0.999. A relationship between maximum biogas yield potential and volatile substrate concentration was established to be ym = −0.0266[VS]2 + 4.8396[VS] + 129.1. An appropriate application of the developed models would lead to an optimal design of a biogas plant digesting cattle/livestock dungs with biogas and organic fertilizers production for farmers and gardeners alike.

Stabilization/solidification of synthetic Nigerian drill cuttings

Abstract: In the Nigerian oil and gas industry, large quantities of oily and synthetic drill cuttings are produced annually. These drill cuttings are heterogeneous wastes which comprises of hydrocarbons, heavy metals and chlorides. Currently, the treatment option for these drill cuttings is thermal treatment, which does not remove these toxic contaminants. In this study, the use of stabilization/solidification as a means of treating synthetic drill cuttings for potential reuse in construction products is investigated. Portland cement was used as a binder. The ratio of water-to-dry binder was 0.4:1. Three different mix ratios of the drill cuttings and binder (2:1, 3:1, 4:1) were investigated. A set of physical tests (Unconfined compressive strength test and Durability test) as well as Toxicity Characteristic Leaching Procedure tests were conducted on the different mixes. For the drill cuttings, the moisture content, sodium adsorption ratio and exchangeable sodium percentage values of 4.04, 6.37 and 7.44% were below the DPR limits of 50, 12 and 15%, respectively. Heavy metals such as arsenic, mercury and silver were below 0.01, 0.001 and 0.001 mg/l compared to the DPR limits of 5, 12 and 5 mg/l, respectively. However, cadmium, chromium and zinc contents of 1.63, 54.80 and 121.17 mg/l were higher than the DPR limits. The unconfined compressive strength test results for the drill cuttings-binder ratios of 2:1, 3:1 and 4:1 were 1040, 606 and 490 psi, respectively much higher than the DPR limit of 20 psi. The Toxicity Characteristic Leaching tests and the Wet/Dry Durability tests produced satisfactory results as well. Key words: Drill cuttings, stabilization, solidification, portland cement.

A review on utilisation of biomass from rice industry as a source of renewable energy

Abstract: Volatile oil price and growing emphasis on environmental conservation have stimulated the development and utilisation of biomass as a vital source of renewable energy. In reducing the global dependency on fossil fuels, rice husk and rice straw which are the widely abundant agricultural wastes from the rice industry have a vital role to play. This paper reviews the key aspects of the utilisation of rice husk and rice straw as important sources of renewable energy. The paper provides some essential background information that includes the physical and chemical characteristics that dictates the quality of these rice biomasses. This paper also describes the various chemical and physical pretreatment techniques that can facilitate handling and transportation of rice straw and husk. Finally, the paper presents the state-of-the-art on thermo-chemical and bio-chemical technologies to convert rice husk and rice straw into energy.

A review of the existing and alternative methods for greener nitrogen fixation

Abstract: The conversion of atmospheric nitrogen into valuable substances such as fertilisers and fine chemicals is essential for agriculture and many other processes that sustain life on the planet. Although the Haber–Bosch process is the most important method of nitrogen fixation, the process is associated with major environmental concerns because it is very energy intensive and requires non-renewable feedstock to generate hydrogen. Hence, alternative ways of nitrogen fixation are being studied, from plasma synthesis and biological processes to metallocomplex catalysis, while existing methods are being improved using novel catalysts. This review covers all of the major areas of nitrogen fixation, discusses the industrial feasibility of each process, the reaction mechanisms, and provides a comparative evaluation of the various nitrogen fixation processes in terms of energy efficiency. Considering energy efficiency, the Haber–Bosch process and non-thermal plasma nitrogen fixation are promising methods for green industrial nitrogen fixation. Although metallocomplex nitrogen fixation takes place at ambient pressures, energy estimations show that this method does not provide higher energy efficiency than biological nitrogen fixation or the Haber–Bosch process. Biological nitrogen fixation on the other hand, has energy efficiency comparable to that of the Haber–Bosch process.

A review on current aspects and diverse prospects for enhancing biogas production in sustainable means.

Abstract: A key strategy allied with today is to develop an alternative energy source instead of fossil fuels in order to compensate present energy need in addition to reduce environmental concerns owed by pollution and global warming. Energy generation in feasible manner without possessing environmental crash is a difficult task where alternative concepts were requisite to ensure sustainable development with accessible technologies. Further advances triggered renewed attention in biogas production technology while it has great impacts on diminishing major economic issues raised in the world. Since the light of these strategies, the present review intended to critically evaluate the recent technological advances and promising prospects coupled with various aspects of biogas production such as sustainable feedstock utilization, microbial and enzyme dynamics, parameter optimization and process segregation, for enhancing this technology in outlook. Appropriate selection, co-digestion, and biotransformation offers a great challenge that crafts substrate to become more energy efficient, besides to trim down the constraints behind principle biomass utilization. A basic framework for process stimulation with microorganisms and enzyme preparations explored that further experimental trials by means of identification of efficient microbes and standardization of enzyme dynamics would augment the feasibility of energy flow during anaerobic digestion. Accordingly, the optimization of various parameters is preferred to accelerate biogas production by resolving the problems occur during anaerobic digestion. Despite the development of multi-stage digester designs intend a breakthrough for process segregation and existing opportunities in this aspect needed further research interest to attain better performance of the system. Moreover, advance simulation approaches using projected prospects from this review would realize significant enhancement of biogas production in the predictable manner.

Applications on agricultural and forest waste adsorbents for the removal of lead (II) from contaminated waters

Abstract: At present, there is growing interest in using low cost, commercially available materials for the adsorption of heavy metals. The major advantages of adsorption technologies are its effectiveness in reducing the concentration of heavy metal ions to very low levels and the use of inexpensive adsorbent materials. In this review, agricultural and forest waste adsorbents were used to remove Pb2+ ions in wastewater treatment, and their technical feasibilities were reviewed in studies mainly from 2000 to 2010. They all were compared with each other by metal binding capacities, metal removal performances, sorbent dose, optimum pH, temperature, initial concentration and contact time. Although commercial activated carbon is widely used in wastewater treatment applications, it has high costs. The use of agricultural by-products as adsorbent material to purify heavy metal contaminated water has become increasingly popular through the past decade because they are less expensive, biodegradable, abundant and efficient. Instead of activated carbon, this study was focused on the inexpensive materials such as agricultural and forest waste. It was shown that these alternative adsorbents had sufficient binding capacity to remove Pb2+ ions from wastewater.