Empirical Model for Predicting Rate of Biogas Production

Rate of biogas production using cow manure as substrate was monitored in two laboratory scale batch reactors (13 liter and 108 liter capacities). Two empirical models based on the Gompertz and the modified logistic equations were used to fit the experimental data based on non-linear regression analysis using Solver tool in Microsoft Excel. The 13-liter reactor was used in Experiments1 & 2 and in Experiment 3 the 108-liter reactor was used. In all the three experiments, Gompertz model gave a better goodness of fit than the modified Logistic model. The cross correlation coefficients for experiment 3 are 0.9972 and 0.9965 for Gompertz and Modified Logistic models respectively. Atomic absorption spectroscopy (AAS) analysis of the biogas indicates that its methane content is above 70% in both reactors.Keywords: Empirical model, Non-linear regression, biogas production, cow manure

Application of adsorbent as a novel technique during biodegradation of a polycyclic aromatic hydrocarbon (anthracene)

The use of an alternative technique as a management strategy for the decontamination of hydrocarbonbased pollution in soil has been advanced in this work. The study investigated the degradation ofanthracene, a three-ringed benzene derivative, in clay soil at ambient conditions under the influence of hydrophilic compound (carbon), thermally activated at temperatures of 300, 500, 700 and 900oC. Thesoil (500 g) was impacted with 1:1 of the contaminant anthracene and activated carbon from groundnut shell in a water medium at a flow rate of 5.0 ml/min. Experimental results revealed that there was asignificant reduction in the level of anthracene in the soil matrix with time. The percentage reduction was found to be directly dependent on the activation temperature. The estimated reaction rate constantwas found to be 0.014/h (control sample without activated carbon) while for the experimental samples, the values ranged from 0.018 - 0.051/h. The study therefore affirms that the presence of activatedcarbon in microbial degradation of anthracene, elicits an enhanced disappearance rate of the hydrocarbon

Application of adsorbent as a novel technique during biodegradation of a polycyclic aromatic hydrocarbon (anthracene)

The use of an alternative technique as a management strategy for the decontamination of hydrocarbonbased pollution in soil has been advanced in this work. The study investigated the degradation ofanthracene, a three-ringed benzene derivative, in clay soil at ambient conditions under the influence of hydrophilic compound (carbon), thermally activated at temperatures of 300, 500, 700 and 900oC. Thesoil (500 g) was impacted with 1:1 of the contaminant anthracene and activated carbon from groundnut shell in a water medium at a flow rate of 5.0 ml/min. Experimental results revealed that there was asignificant reduction in the level of anthracene in the soil matrix with time. The percentage reduction was found to be directly dependent on the activation temperature. The estimated reaction rate constantwas found to be 0.014/h (control sample without activated carbon) while for the experimental samples, the values ranged from 0.018 - 0.051/h. The study therefore affirms that the presence of activatedcarbon in microbial degradation of anthracene, elicits an enhanced disappearance rate of the hydrocarbon

The removal of heavy metal ions from aqueous solutions using sour sop seeds as biosorbent

Heavy metals discharged into the environment from various industries constitute one of the major causes of water and soil pollution. Conventional methods for the removal of heavy metals from waste waters are often cost prohibitive. These constraints have caused the search for alternative technologies for metal sequestering to cost-effective environmentally acceptable levels. One of the exploitations is the use of biomaterials. The results obtained after contacting for 120 min showed that sour sop seeds achieved the removal of 77.6, 68.5, 56.4and 40.6% for Cu2+ , Ni2+, Zn2+ and Pb2+ ions, respectively. The residual metallic ion concentrations were determined using an Atomic Absorption Spectrophotometer (AAS). The ability of sour sop seeds to absorb metal ions as shown from the results can be used for the development of an efficient, clean and cheap technology for effluent treatment

The use of antioxidants in vegetable oils – A review

The shelf life of vegetable oils in food uses and their applicability in industrial situations is greatly dependent on their oxidative stabilities. Methods of improving oxidative stability values currently available include genetic modifications, compositional changes via chemical means, as well as the inhibition of oxidation by means of substances known as antioxidants. This paper reviews the properties of vegetable oils which predispose them to auto oxidation reactions, explores the nature andmechanisms of the operation of antioxidants in brief, and finally summarizes current research efforts geared towards identifying and evaluating the effectiveness and commercial promise of less toxic newantioxidants derived as natural extracts from various plant species

Biodegradation of mineral oils – A review

The uses of the various kinds of mineral oils in various industrial situations have made them an indispensable ingredient of the industrialization and development that has characterized the past century. Recent focus on health, safety and the preservation of the environment has turned the searchlight to the effects of mineral oils on the environment when they are accidentally spilled, or intentionally disposed of. Biodegradation, which provides an indication of the persistence of a particular substance in the environment, is the yardstick for assessing the eco friendliness of substances. Due to the poor biodegradation rates observable for mineral oils, various methods of bioremediation are currently being researched, with the isolation of various microbial species with the ability to use up mineral oils as a carbon and energy source. Ultimately, vegetable oil based hydraulic fluids will come to the fore as a suitable and more  nvironmentally friendly solution to the demand for hydraulic fluids