Effects of Oil and Salt Water Spills on the Growth of A Fresh-Water Algae

Abstract This study investigated the effects of oil spill and inundation of sea water into lakes and rivers on the growth of a fresh-water algae. Test results showed that oil and salt water affected the growth of the fresh-water algae

Removal of Lead from Wastewater Using a Biosurfactant

Abstract Lead removal form wastewater was studied using the UH-biosurfactant. Lead concentration varied from 10 to 100 mg/L and pH varied from 2.5 to 12. Commercially available surfactants such as SDS and Triton X-100 were also used for comparison. Results have shown that biosurfactant removed over 75% of lead from water and the optimum lead-biosurfactant ratio was 0.01

Identification of UH-Biosurfactant Producing Bacteria Using the Molecular Method

Abstract In this study, UH-biosurfactant producing bacteria was isolated and identified as Serratia sp. using the molecular method. Using the Basic Local Alignment Search Tool (BLAST) available in the National Center for Biotechnology Information (NCBI) database, there was 100% matching with Serratia marcescens when the 16S ribosomal RNA (16S rRNA) gene was used, and highest matching of 91% with Serratia plymuthica when RNA polymerase sigma 70 (sigma D) factor (rpoD) gene was used. Introduction Biosurfactant is used widely in environmental remediation field for petroleum and heavy metal pollution removal, by reducing surface tension between surfaces. It is also non-toxic, and biodegradable without second pollution. UH biosurfactant has been proven to be quite effective for enhancing the solubility of perchloroethylene (PCE), tetrachloroethylene (TCE), toluene, naphthalene, and phenanthrene in water, and removal of lead (Ghurye 1993; Hariharan 1996; Ren 1998; Srinivas 2005; Harendra 2006). Identification of the bacteria using the molecular method is fast and accurate, and is commonly used for modern bacteria identification. The 16S rRNA is a 1542 nt long component of the small prokaryotic ribosomal subunit, and it is used for bacteria identification in phylogenetic studies as it is highly conserved and contains hypervariable regions, providing species-specific signature sequences. A sigma 70 factor encoded by rpoD gene is a factor controlling gene expression in bacteria, and is a protein essential for survival, this factor is also appropriate for bacteria identification in phylogenetic analysis, as it rarely spreads horizontally and has an appropriate rate of evolution

Correlation of Thornthwaite Climate Index (TI) with Rainfall and Suction in Houston

Abstract: Thornthwaite moisture index (TI) can be used to characterize the cyclic nature of climatic wetting and drying of soils. TI can be used to predict the active zone and suction profiles of the soil. In this study Thornthwaite moisture index for Houston was studied and compared with the annual rainfall and suction measured in the active zone

Some Failure Patterns in Small Diameter Water Pipelines in the City of Houston

Abstract: In this study, types of water pipeline failures in the City of Houston were investigated. Based on limited data, the most common failure mode was circumferential crack which always happened in small diameter cast iron or asbestos cement pipes. Based on preliminary analysis, the failure was a combination of corrosion and mechanic forces

Geotechnical Engineering Challengers in the Houston Area

ABSTRACT: Rapid growth in the urban areas such as Houston in Texas is leading to construction of civil infrastructure facilities, including bridges and highways on soft clays. Identify the pockets of soft clays and their consolidation properties are critical for designing facilities with no stability and settlement problems. In this study, soft clays are characterized based on their mineralogy, physical and mechanical properties. The X-ray diffraction (XRD) and scanning electron microscope (SEM) studies were performed to investigate the mineral composition and microstructure of the clays respectively. Both CL and CH soft clays are present in the Houston area. Based on over 100 data sets, statistical mean, standard deviation, variance and coefficient of variance and distribution of properties and property correlations for the CL and CH soft clays have been developed. The natural moisture content of 97% of the soft clay was lower than the liquid limit. Overestimation of settlement on overconsolidated soft clays may require ground improvement before construction with added delay and cost to a project. Since the soft soil shear strength is low, the structures on the soft soils are generally designed so that the increase in stress is relatively small and the total stress in the ground will be close to the pre-consolidation pressure. Hence the recompression index, determined from a consolidation test is very important parameter in estimating the settlement. Although recompression index has been quantified in the literature, its determination may not be applicable to all soft soils in its current form. The influence of stress level on the recompression index is not clearly quantified. This study also focused on developing methods for determining the recompression index of over-consolidated soft clay soils. Based on the methods used to determine the recompression index, over 750% difference in the minimum and maximum C r values was observed for the Houston area soft clay.

Effect of Micro-Sand on the Curing of Modified Smart Cement

Abstract: Electrical resistivity at room temperature was monitored during the early age curing of oil well cement (class H) with water-to-cement ratio of 0.38 and modified with micro-sand. In this study, up to 9% of micro-sand by (weight of cement) was used. Effect of different percentage of micro-sand on the density of the oil well cement was also investigated. It was found that addition of 9% of the micro-sand increased the initial electrical resistivity of the cement by 14% and increased the minimum electrical resistivity (ρmin) by 38% and time to reach the minimum electrical resistivity (tmin) decreased by 30%. Density of smart cement increased by 2% when the micro-sand percent was 9%. The electrical resistivity at the end of 24 hr increased from 4.12 Ω-m to 4.32 Ω-m by adding 9% of micro-sand

Optimizing the rheological properties of silica nano-modified bentonite mud using overlaid contour plot and estimation of maximum or upper shear stress limit.

An optimization based statistical (response surface) approach was used to evaluate the rheological properties of bentonite mud treated with silica nanoparticles. The overlaid contour plot established the feasible region for the various factor settings from multiple regression equations. The steepest method was used to further determine the optimal factor settings for minimum rheological properties and this was established at 6.3 wt.% bentonite content and 0.94 wt.% silica nanoparticles. The rheological properties of the bentonite mud containing and without silica nanoparticles was evaluated using a Hyperbolic (new) model and related with other oil industry based models: Herschel Bulkley, Sisko, Casson. The hyperbolic rheological model estimated the rheological behaviour of the nano-modified mud satisfactorily while also predicting a shear stress limit for the nano-modified mud. The maximum shear stress limit values for 6.3, 13 and 15 wt.% mud were 14.59, 61.74 and 107.4 Pa respectively. Upper shear stress values obtained from a 1.5 wt.% silica nanoparticle modified 6.3, 13 and 15 wt.% bentonite mud were 22.27, 72.62 and 171.3 Pa respectively, which represents an increment of 34.5 to 37.4% in the upper limit of shear stress. The effect of silica nanoparticles on the upper shear stress limit was quantified using a response surface design

Using waste to reduce slope erosion on road embankments

“Permission is granted by ICE Publishing to print one copy for personal use. Any other use of these PDF files is subject to reprint fees" (www.transport-ice.com). http://dx.doi.org/10.1680/tran.2006.159.1.15Urban waste may be used to reduce slope erosion of highway embankments. Whereas different kinds of compost have been tested in the USA for highway revegetation, sewage sludge has been used only for agricultural purposes. This paper presents the results of research carried out in order to study the viability of the application of sewage sludge compared with compost. Test areas measuring 4 m 3 5 m were constructed on a new highway embankment with 2 : 1 and 3 : 2 side slopes in the south of Spain. Crop cover and erosion were evaluated for plots with application of three dosages of compost and three dosages of sludge. Also, the costs of the proposed application are analysed. This treatment costs, on average, 0.24% of the budget for new roads infrastructure, and reduces soil loss by up to 30% on average. Based on these results, compost and sludge can be successfully used to reduce slope erosion on highway embankments. However, standards and specifications are required for their routine application.Department of Civil Engineering, University of Granada, Spai

Nanotechnology and global energy demand: challenges and prospects for a paradigm shift in the oil and gas industry.

The exploitation of new hydrocarbon discoveries in meeting the present global energy demand is a function of the availability and application of new technologies. The relevance of new technologies is borne out of the complex subsurface architecture and conditions of offshore petroleum plays. Conventional techniques, from drilling to production, for exploiting these discoveries may require adaption for such subsurface conditions as they fail under conditions of high pressure and high temperature. The oil and gas industry over the past decades has witnessed increased research into the use of nanotechnology with great promise for drilling operations, enhanced oil recovery, reservoir characterization, production, etc. The prospect for a paradigm shift towards the application of nanotechnology in the oil and gas industry is constrained by evolving challenges with its progression. This paper gave a review of developments from nano-research in the oil and gas industry, challenges and recommendations