Effects of Different Concentrations of Biocides on Fungal Populations, Isolated from Biofilms of Corroded Oil Pipelines, Niger Delta Region, Nigeria

Microbiologically influenced corrosion is a problem commonly encountered in facilities in the oil and gas industries. The present study described fungal enumeration and identification in biofilms of oil pipelines in Oshie flow station in Rivers State and Irri flow station in Delta State, Nigeria using traditional cultivation technique.  The fungal species isolated in biofilms from the two sites are as follows Verticillium dahlae, Saccharomyces cerevisiae, Penicillium corylophilum, Botrytis cinerea, Fusarium oxysporum, Aspergillus paradoxus, Humicola grisae, Aureobasidium pullulans, Monilia balanitis, Hormoconis resinea, Asperillus flavus and Helimenthosporium maydis. The study also focuses on the use of three biocides to inhibit or eliminate the identified organisms in order to minimize the material and financial losses encountered by oil and gas companies, because of microbiologically influenced corrosion (MIC). The performance of three biocides (ozone, sodium hypochlorite and formaldehyde) at the concentrations of 0, 1, 2, 3, 4 and 5% in eliminating the fungal species isolated from biofilms of oil pipelines in Rivers and Delta States, Niger Delta, Nigeria. It is shown, that formaldehyde, ozone exhibited the best biocidal characteristics and concentrations of 1 and 2 % eliminated almost all the fungal species after 72 hours of contact time. This study is relevant to the problem of microbiologically influenced corrosion as the data may contribute to elucidate which fungal species contribute to the MIC process and to gain a better understanding of the fungal community of biofilms. This study will give us better understanding of the biocide capable of eliminating fungal species in biofilm of oil and gas pipelines. Keywords: Concentration, fungal population, biocides, microbiologically influenced corrosion, biofilm

Effects of Different Concentrations of Biocides on Fungal Populations Isolated from Biofilms of Corroded Oil Pipelines

Microbiologically influenced corrosion is a problem commonly encountered in facilities in the oil and gas industries. The present study described fungal enumeration and identification in biofilms of oil pipelines in Oshie flow station in Rivers State and Irri flow station in Delta State, Nigeria using traditional cultivation technique.  The fungal species isolated in biofilms from the two sites are as follows Verticillium dahlae, Saccharomyces cerevisiae, Penicillium corylophilum, Botrytis cinerea, Fusarium paradoxus, Aspergillus paradoxus, Humicola grisae, Aureobasidium pullulans, Monilia balanitis, Hormoconis resinea, Asperillus flavus and Helimenthosporium maydis. The study also focuses on the use of three biocides to inhibit or eliminate the identified organisms in order to minimize the material and financial losses encountered by oil and gas companies, because of microbiologically influenced corrosion (MIC). The performance of three biocides (ozone, sodium hypochlorite and formaldehyde) at the concentrations 0, 1, 2, 3, 4 and 5% in eliminating the fungal species isolated from biofilms of oil pipelines in Rivers and Delta States, Niger Delta, Nigeria. It is shown that formaldehyde an ozone exhibit the best biocidal characteristics and concentrations of 1 and 2 % eliminated all to almost the fungal species after 72 hours of contact time. This study is relevant to the problem of microbiologically influenced corrosion as the data may contribute to elucidate which fungal species contribute to the MIC process and to gain a better understanding of the fungal community of biofilms. This study will give us better understanding of the biocide capable of eliminating fungal species in biofilm of oil and gas pipelines. Key word: Concentration, fungal population, biocides, microbiologically influenced corrosion, biofilm

Phytoremediation of Diesel Oil Polluted Soil by Fluted Pumpkin (Telfairia Occidentalis Hook F.) in Uyo, Niger Delta Region, Nigeria

Phytoremediation is an emerging technology for cleaning contaminated soils. In this study, the effect of fluted pumpkin (Telfaira occidentalis Hook F.) on the degradation of petroleum hydrocarbon in a diesel oil contaminated soil was investigated. Fluted pumpkin seeds were planted in each treatment (0.00, 1.11, 1.59, 2.50 and 3.06%) for a period of 18 weeks. The following parameters were determined: germination percentage, length of vine, number of leaves per vine, leaf yield and the dry weight of leaves and vines on the 3rd, 6th, 9th, 12th and 15th weeks after planting (WAP). Total petroleum hydrocarbon (TPH) was determined on the 2nd and 18th weeks after oil pollution (WAOP). Total bacterial and fungal counts were determined on the 3rd, 6th, 9th, 12th, 15th and 18th WAOP. The results demonstrated that diesel affected soil depressed seed germination. Length of vine and number of leaves per vine were observed to increase from 3rd to 15th WAOP. Leaf yield increased from 3rd to 9th WAOP and thereafter declined from 12th to 15th WAOP. The results further revealed reduction in dry matter of leaves as concentration of oil increases, whereas dry weight of vines increased with increasing oil pollution. The result also demonstrated that fluted pumpkin stimulated total bacterial and fungal number. Total petroleum hydrocarbon (TPH) removal in the polluted soil was observed to be 86.53, 94.38, 92.80 and 92.97% in 1.11, 1.59, 2.50 and 3.06% concentration respectively. Thus, fluted pumpkin has proved to be efficient for removal of TPH from oil-contaminated soil. Keywords: Phytoremediation, diesel oil, fluted pumpkin, contaminated soils, petroleum hydrocarbo

Evaluation of Some Properties of Soils Affected by Diesel Oil Pollution in Uyo, Niger Delta Area, Nigeria

Soil pollution due to oil spill is a common problem in the Niger Delta region of Nigeria. This necessitated the experiment to determine the effect of diesel oil pollution on some soil properties in Uyo within the Niger Delta region of Nigeria.  The experiment was conducted at the University of Uyo Teaching and Research Farm in 2009. It was laid out in a completely randomized design (CRD) in triplicates.  The size of the experimental plot was 60.7m2, sub-divided into three sub-plots each measuring 20.24m2. Each sub-plot was divided into five experimental units receiving the following treatments: 0 (control), 8, 11.5, 14.5 and 22.0 litres of diesel oil, which was converted into 0.0%, 1.39%, 2.50%, 3.45% and 5.06%. The results at two weeks after oil application (2WAOA) showed significant decrease in soil pH from  4.90 in the control  to 4.35 in 5.06% pollution levels resulting in soil reaction being rated as extremely acid in oil polluted soils compared to the control with soil/reaction being rated as very strongly acid. There was depletion in total nitrogen and basic cations such as Ca2+, Mg2+, Na+ and K+. at 2WAOA. Carbon/nitrogen ratio increased in all the treatments, with the highest pollution level (5.06%) having 114.33±1.41. Percent base saturation increased inconsistently across the treatments with the highest being 56.96±0.003% (for 2.50% pollution) and the lowest being 44.24±0.008% (for 5.06% pollution level). The results at 18WAOA showed varying degrees of increase in the soil pH. The control plot had the pH of 6.39±0.002 and the highest pollution level of 5.06% had the pH of 6.05±0.2. The soil reaction at 18 WAOA was rated slightly acid compared to extremely acid in 2WAOA. There were varying degrees of increase in organic carbon in all the treatments. Total nitrogen also increased at 18WAOA, the increase ranged from 50-80%. Carbon/Nitrogen ratio was significantly reduced (? < 0.05) across the treatments.  Basic cations and percent base saturation increased across the treatments at 18WAOA. Correlation between concentrations of diesel oil in the soil and some soil properties at 2WAOA and 18 WAOA showed that at 2 WAOA soil pH, total N and percent base saturation showed negative correlation, while organic carbon and carbon/nitrogen ratio showed positive correlation. At 18 WAOA, organic carbon and total N, showed positive correlation, while soil pH, carbon/nitrogen ratio and percent base saturation showed negative correlation. Keywords: Evaluation, Soil Properties, Oil polluted, Niger Delta Area, Nigeri

*Corresponding Biocidal Effects of Ozone, Sodium Hypochlorite and Formaldehyde, on Sulphate Reducing Bacteria Isolated from Biofilms of Corroded Oil Pipelines in the Niger Delta, Nigeria

The performance of three biocides (ozone, sodium hypochlorite and formaldehyde) on Sulphate reducing bacteria was tested. The Sulphate reducing bacteria were isolated from biofilms of corroded oil pipelines under normal flow condition. The study was aimed at controlling these bacteria using the three biocides at different concentrations (0, 1, 2, 3, 4 and 5 percent) in order to reduce the economic losses normally encountered in the oil and gas industry due to the activities of Sulphate reducing bacteria. The results showed that ozone was effective from 1% concentration by completely eliminating Desulfuromonas acetoxidans, Desulfobulbus propionicus and Desulfosarcina variabilis followed by sodium hypochlorite and then formaldehyde being the least effective. For proper monitoring and control of microbiologically influenced corrosion caused by sulphate reducing bacteria, Ozone and one of the non-oxidizing biocides such as formaldehyde should be used