Management and disposing of used lubricating oil (ULO) poses deleterious effects to air, land and water pollution. These contaminants not only causes environmental problems, they also have bio-accumulation effects on living organisms, reduces the inhabitants lifespan as a result of the diseases spread, poisoning and fouling of catalyst as well as corrode processing equipment. The contaminants removal in used lubricating oil is a major step to avoid pollution as discussed thoroughly by many researchers in literature. In addition, to curbing pollution, another advantage is converting waste to wealth. This review paper presents insight into various methods for removal of contaminants in used lubricating oil. The advantages and drawbacks of each method were earmarked for further study.

The use of Microbial Fuel Cells to produce electricity is an area that has attracted attention recently owing to clean and renewable energy produced by the use of bacteria to catalyze the conversion of organic matter into electricity. The experiment was done in a mediator-less Microbial Fuel Cell with cassava mother liquid, human urine, human urine with faeces, swine waste and brewery waste as substrates using potassium ferricyanide as electron acceptor. The result of the experiment indicates that cassava mother liquid, human urine and swine waste generated a maximum potential difference of 1.32V each and also maximum current of 2.28A,2.19A and 2.02A respectively. However, human urine with faeces and brewery waste was observed to be lower with values 1.13V and 1.15V respectively and corresponding lower currents of 1.45A and 1.40A respectively. It was observed that human urine is most stable with potential difference and current of 1.32V and 1.58A respectively. This may be attributable to the rich organic compounds such as carbohydrate, nitrogen, ammonium, potassium and phosphorous in urine which are good sources of fuel.

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This paper investigated the use of extract from groundnut shells as a natural coagulant for the reduction of turbidity in abattoir wastewater using the coagulation process. The ideal concentration of NaCl for coagulant extraction was established through a series of jar tests. The effects of process variables of coagulant dosage (1-5 g/L), settling time (0-60 min), pH (2-10) and temperature (298-318 K) on the turbidity reduction efficiency were examined using a bench-scale jar test. At an optimal condition of 4g/L, pH 8, temperature of 318K, and settling period of 20 minutes, a reduction efficiency of 94.33% was achieved. The Second-order per-kinetic theory of Von-Smoluchowski’s was used for kinetic evaluation at temperatures of 298 K, 308 K and 318 K. At a temperature of 298 K, the experimental data fit perfectly into the Von-Smoluchowski second-order per-kinetics theory, with a correlation coefficient of 0.952, coagulation rate constant of 0.00002 L/(mg.min), collision efficiency of 8.703exp12 and coagulation time of 48.27 min, establishing that the rapid coagulation theory holds true for the coagulation of abattoir wastewater using groundnut shell extract and under the experimental conditions. As a result of the findings, it is proposed that groundnut shell extract, which is readily available and environmentally safe, is effective for turbidity reduction of sewage water and can be used as an alternative to chemical coagulants for the pre-treatment of abattoir wastewater.