Oil contaminated sand: an emerging and sustainable construction material

Crude oil spillage severely impacts the environment and affects the physical and chemical properties of the surrounding soil. Due to prohibitive cost of cleaning and disposing oil contaminated sand, mixing and stabilizing them with cement and using them in construction is now considered as an alternative and cheap remediation method. In this paper, the effect of o il contamination on the mechanical properties of sand and its concrete were reviewed . In addition, the results of the on-going research and development on the effects of light crude oil contamination on the properties of fine sand and the produced mortar are presented. For fine sand contaminated with light crude oil, it was found that the cohesion increased significantly up to 1% of oil contamination and then decreased with increasing percentage of crude oil while a slight reduction in frictional angle was observed with oil contamination. The highest compressive strength was obtained for mortar with 1% oil contamination and with only a 18% decrease in strength of mortar with 10% oil contamination compared to the uncontaminated samples. More importantly, the compressive strength of mortar with oil contaminated sand was found suitable for some engineering applications indicating their high potential and beneficial use as an emerging and sustainable material in building and construction

Physical and mechanical properties of cement mortar containing fine sand contaminated with light crude oil

Oil contaminated sand resulting from oil leakage has continuously been a major environmental concern worldwide. This problem affects the physical and chemical properties of the surrounding soil. Due to prohibitive cost of the existing remediation methods for oil contaminated sand, mixing them with cement and using in construction is considered as a cheaper alternative. In this study, the effect of light crude oil contamination on the physical and mechanical properties of cement mortar was investigated. Fine sand with different percentages of light crude oil by weight ranging from 0% to 10% was mixed with Ordinary Portland cement and cured in a fog room. The compressive strength of the cement mortar was then determined at 7, 14 and 28 days. Results showed that the workability and the total porosity of the cement mortar increased as the amount of crude oil increases. Moreover, the compressive strength increased with the increasing curing time for all specimens. The cement mortar containing fine sand with 1% light crude oil exhibited the highest compressive strength, which is 18%, 30% and 17% higher than the uncontaminated samples at 7, 14 ad 28 days, respectively. Interestingly, the cement mortar with up to 2% oil contamination has higher compressive strength than the 0% oil contamination while increasing the crude oil content more than 2% and up to 10% cause a reduction in the compressive strength by 50%. Still, the strength properties of mortar with oil contaminated sand up to 10% are suitable for landfill layering and production of bricks results indicating their high potential and beneficial use as a sustainable material in civil engineering and construction

Oily wastewater treatment: removal of dissolved organic components by forward osmosis

Produced water is water brought to the surface with crude oil or natural gas; it is the largest waste stream by volume associated with the production of oil and gas. Some crude oil and traces of organic compounds, particularly organic acids, are known to occur in produced water. Although the current international standard limits the amount of dissolved oil in produced water to less than 30 mg/L prior to environmental discharge, no regulations exist for other dissolved organic constituents. This is mostly because of the lack of low cost, high efficiency technologies capable of removing dissolved organic constituents from produced water. This work investigated the removal of dissolved organics from produced water by the forward osmosis (FO) process, with a particular focus on Libya. In an off-shore platform, seawater can be utilised as the draw solution for the FO process as it allows for a significant reduction in the cost of treatment before discharging produced water into the sea. Two membranes specifically designed for the FO process (namely HTI-Cartridge and HTI-Pouch) provided by Hydration Technology Innovation and two typical NF membranes (namely NF270 and NF90) provided by Dow Chemical were used in this study. Acetic acid was selected as a model organic acid and a synthetic oil-in-water emulsion was prepared using motor cycle oil (Fork w2.5) in Milli-Q. The water flux, reverse salt flux, the rejection of acetic acid, and the effects of concentrated oil in produced water were systematically evaluated. This investigation appears to be the first attempt to study the removal of dissolved components from produced water using an FO membrane. Water flux and reverse salt flux were investigated at different pH values (un-adjusted pH, pH4, and pH6), and the results showed that the HTI-Cartridge membrane produced a higher permeate flux than the HTI-Pouch membrane when the same draw solution concentration was used in the FO mode (e.g. active layer facing the feed solution). On the other hand, there were no significant differences in the water flux and reverse salt flux at different pH values for each individual membrane. The transport phenomena of the HTI-Cartridge were also investigated since it performed better as a permeate flux than the HTI-Pouch membrane. An HTI-Cartridge membrane was evaluated in the FO and pressure retarded osmosis (PRO) modes (in the PRO mode, the active layer of the membrane is in contact with the draw solution). Higher water flux and reverse salt flux were observed under the PRO mode rather than the FO mode because the internal concentration polarisation (ICP) phenomenon which is considered to be unique in the FO process. The performance of the FO membranes (HTI-Cartridge and HTI-Pouch) and NF membranes (NF-90 and NF-270) were also investigated under reverse osmosis (RO) mode and the results were compared with the FO mode. The rejection of acetate by the FO and NF membranes was strongly pH-dependent. At near neutral pH (6.7-7.3), acetate rejection by either the HTI-Cartridge or HTI-Pouch membranes was almost 100%. The rejection of acetate decreased dramatically as the feed solution pH decreased to pH 4, although both of them rejected acetate more efficiently under FO mode where the active layer faced the feed solution and the backing layer faced the draw solution. Acetate rejection by the NF-270 and NF-90 membrane was considerably lower than the FO membranes. The rejection of acetate increased from 55% to 92% with the NF-90 membrane, as the feed pH increased from 4 to 9. Similarly, the rejection of acetate by the NF-270 membrane (which has a larger pore size than the NF-90 membrane), increased from as low as 2% to 89% as the feed pH increased from pH 4 to pH 9. In the FO mode, acetate rejection was also strongly pH dependent. More importantly, acetate rejection in the FO mode was at least 10 % higher than in the RO mode. In addition, the allowable oil content (30 mg/L) did not affect acetate rejection in either the FO or RO modes. Furthermore, the allowable oil content of 30 mg/L did not cause any discernible membrane fouling in either the FO or RO modes. The reported results indicate that a highly efficient removal of acetate from produced water can be achieved using the FO process without pH adjustment, because the pH range of the produced water produced from light crude oil is usually from pH 6 to pH 7.7

Comparison between oily and coal seam gas produced water with respet to quantity, characteritics amd treatment technologies: a review

Oil and gas are significant sources of energy worldwide, and their importance increases due to the ever increasing global demand for energy. The production of conventional oil, atural gas, and unconventional gas, for example, of coal seam gas (CSG) or coal bed methane, is usually accompanied with contaminated water. This article reviews the similarities and differences between the water produced during exploitation of conventional hydrocarbon and unconventional CSG resources in terms of quantity, characteristics, current treatment and a promising alternative treatment that can be used. The volume of produced water from conventional oil and gas exploitation increases during the operating life of a well. In contrast, in CSG exploitation, produced water is generated from an early stage in large volumes. Characteristics of oily and CSG produced water differ considerably from each other in terms of organic content (e.g. the occurrence of oil and grease and specific petroleum organic contaminants such as benzene, toluene, ethylbenzene, and xylene or BTEX), ionic composition and total dissolved solids. In general, methods for treating and disposing oily produced water are more established but somewhat less stringent given the long history of conventional oil and gas extraction. On the other hand, the treatment of CSG produced water requires a more comprehensive and stringent treatment train and almost always involves reverse osmosis filtration, particularly if the treated water is for beneficial reuse. Membrane filtration technologies have played and will continue to play a major role in the treatment of produced water. Several new membrane processes, particularly forward osmosis, have also emerged as notable candidate technologies for sustainable management of produced water from the oil and gas industry

Mechanical properties of mortar with oil contaminated sand

The use of oil-contaminated sand in construction is now being considered as an alternative and cost effective remediation method to minimize its adverse effect in the environment. In this study, the effect of oil contamination on the mechanical properties of mortar under two different mixing methods and three different w/c ratios 0.4, 0.5 and 0.6 were investigated. Three different percentages of crude oil contamination (0, 2 and 10%) were considered. Similarly, the mortar was prepared using two mixing methods, i.e (i) cement is mixed with water first before sand is added (CWS) and (ii) cement and sand was mixed first before adding water (CSW) to examine its effect on the compressive strength. The results indicated that the oil contamination affects the compressive strength of mortar. While the compressive strength of 0 and 2% oil contamination is almost the same, a 25% of compressive strength reduction was obtained for 10% crude oil contamination. On the other hand, CWS provided higher compressive strength than the CSW mixing method under different crude oil content. These results show the importance of mixing method especially for mortar with sand with high percentage of crude oil contamination. While the optimum compressive strength was observed with w/c of 0.5 compared to 0.4 and 0.6. Furthermore, the results indicated that oil contaminated sand has the potential for use in construction application

Comparison between oily and coal seam gas produced water with respect to quantity, characteristics and treatment technologies: a review

Oil and gas are significant sources of energy worldwide, and their importance increases due to the ever increasing global demand for energy. The production of conventional oil, atural gas, and unconventional gas, for example, of coal seam gas (CSG) or coal bed methane, is usually accompanied with contaminated water. This article reviews the similarities and differences between the water produced during exploitation of conventional hydrocarbon and unconventional CSG resources in terms of quantity, characteristics, current treatment and a promising alternative treatment that can be used. The volume of produced water from conventional oil and gas exploitation increases during the operating life of a well. In contrast, in CSG exploitation, produced water is generated from an early stage in large volumes. Characteristics of oily and CSG produced water differ considerably from each other in terms of organic content (e.g. the occurrence of oil and grease and specific petroleum organic contaminants such as benzene, toluene, ethylbenzene, and xylene or BTEX), ionic composition and total dissolved solids. In general, methods for treating and disposing oily produced water are more established but somewhat less stringent given the long history of conventional oil and gas extraction. On the other hand, the treatment of CSG produced water requires a more comprehensive and stringent treatment train and almost always involves reverse osmosis filtration, particularly if the treated water is for beneficial reuse. Membrane filtration technologies have played and will continue to play a major role in the treatment of produced water. Several new membrane processes, particularly forward osmosis, have also emerged as notable candidate technologies for sustainable management of produced water from the oil and gas industry

Effects of light crude oil contamination on the physical and mechanical properties of fine sand

The use of oil-contaminated sand in building and construction is now being considered as an alternative and cost-effective way to minimize its adverse effect on the environment. To achieve this, the effect of oil contamination on the important mechanical properties of sand should be investigated first. This study investigated the effect of petroleum-derived contaminants on the water absorption, permeability, cohesion, friction angle, and shear strength of fine sand. Contaminated samples were prepared by mixing fine sand with different percentages of light crude oil (0 to 20%). The results indicated that the water absorption of fine sand decreases with an increase in crude oil. An increase in the cohesion was observed for sand with up to 1% of oil contamination, after which the cohesion began to decrease, which also results in the reduction in the permeability. A slight reduction in the friction angle was found for oil-contaminated fine sand. At a low normal stress of 50 kPa, as the percentage of light crude oil increased, the shear strength increased up to 1% of oil contamination and then it decreased. These results provided useful information on how oil contaminated sand can be used safely and effectively in building and construction

Effect of light hydrocarbons contamination on shear strength of fine sand

Shear strength is one of the most important soil properties in geotechnical engineering and design. This property can be affected by several pollution sources such as crude oil. To investigate the effects of oil contamination, fine sand mixed with various amounts of light crude oil, ranging from 0 to 20% by mass were prepared. Direct shear test was conducted to determine the friction angle and cohesion of oil contaminated sand. Results showed that soil cohesion at its highest value of (10.7 kPa) at 1% oil contamination and decreases with as the oil contamination increases. Meanwhile, a slight reduction in the friction angle is observed when oil is added into the fine sand by as much as 20%. In general, the oil contamination is found to decrease the shear strength of fine sand. The results of this study will benefit engineers and decision makers in recycling or re-using of oil contaminated sand for building and construction

An overview on oil contaminated sand and its engineering applications

Oil leakage is considered as one of the significant environmental issue worldwide, which affects the physical and chemical properties of the surrounding sand. A range of remediation methods for oil-contaminated sand was recommended but none are considered to be cost effective especially in developing countries. In order to find an alternative and cost-effective remediation method, the use of oil contaminated sand in engineering and construction has been considered. This paper reviews the main sources of oil contamination, the existing remediation methods and critically analysed several factors that affecting the properties of oil contaminated sand. Emerging applications of oil contaminated sand in engineering and construction are also presented

Potential pozzolanicity of Algerian calcined bentonite used as cement replacement: optimisation of calcination temperature and effect on strength of self-compacting mortars

The effect of using calcined bentonite (CB) as a partial replacement for Ordinary Portland cement (OPC) in self-compacting mortar (SCM) is investigated. The pozzolanicity of this calcined clay is evaluated using the strength activity index and TG/ATD analysis. The cement in SCM has been replaced with CB at 0, 5, 10, 15, 20, 25 and 30% by mass of cement. The effect of CB on fresh SCM properties is examined using mini-slump flow and V-funnel flow time. The compressive strength is determined at the age of 3, 7 and 28days, and the ultrasonic pulse velocity (UPV), hardened density and water absorption are determined at the age of 28days. The behaviour of SCM exposed to high temperature is also studied. The results indicate that CB significantly decreased the flowability of SCM, but these results are good enough for SCM and SCC production. Incorporating 10 and 15% of CB improves the compressive strength and UPV. Water absorption tends to increase slightly with an increase in CB content and there is a decrease in density as the amount of CB increases. SCM containing CB is stronger when exposed to high temperature than those exposed to normal temperature (23C)