Produced water handling has been an issue of concern for oil and gas producers as it is one of the major factors that cause abandonment of the producing well. The development of effective produced water management strategies poses a big challenge to the oil and gas industry today. The conversion of produced water into irrigation or fresh water provides a cost effective tool to handle excessive amounts of the produced water. In this research we proposed on-site produced water treatment units configured to achieve maximum processing throughput. We studied various advanced separation techniques to remove oil and dissolved solids from the produced water. We selected adsorption as the oil removing technique and Reverse Osmosis (RO) as the dissolved solids removing technique as being the best for our purpose. We performed experiments to evaluate operating parameters for both adsorption and RO units to accomplish maximum removal of oil and dissolved solids from the produced water. We compared the best models fitting the experimental data for both the processes, then analyzed and simulated the performance of integrated produced water treatment which involves adsorption columns and RO units. The experimental results show that the adsorption columns remove more than 90% of the oil and RO units remove more than 95% of total dissolved solids from the produced water. The simulation results show that the proper integration and configuration of adsorption and RO units can provide up to 80% efficiency for a processing throughput of 6-8 gallons per minute of produced water. From an oil and gas producer’s viewpoint output from the produced water treatment system is a revenue generating source. The system is flexible and can be modified for the applications such as rangeland restoration, reservoir recharge and agricultural use.

Produced water handling has been an issue of concern for oil and gas producers as it is one of the major factors that cause abandonment of the producing well. The development of effective produced water management strategies poses a big challenge to the oil and gas industry today. The conversion of produced water into irrigation or fresh water provides a cost effective tool to handle excessive amounts of the produced water. In this research we proposed on-site produced water treatment units configured to achieve maximum processing throughput. We studied various advanced separation techniques to remove oil and dissolved solids from the produced water. We selected adsorption as the oil removing technique and Reverse Osmosis (RO) as the dissolved solids removing technique as being the best for our purpose. We performed experiments to evaluate operating parameters for both adsorption and RO units to accomplish maximum removal of oil and dissolved solids from the produced water. We compared the best models fitting the experimental data for both the processes, then analyzed and simulated the performance of integrated produced water treatment which involves adsorption columns and RO units. The experimental results show that the adsorption columns remove more than 90% of the oil and RO units remove more than 95% of total dissolved solids from the produced water. The simulation results show that the proper integration and configuration of adsorption and RO units can provide up to 80% efficiency for a processing throughput of 6-8 gallons per minute of produced water. From an oil and gas producer’s viewpoint output from the produced water treatment system is a revenue generating source. The system is flexible and can be modified for the applications such as rangeland restoration, reservoir recharge and agricultural use.

Forward osmosis (FO) is one of the emerging membrane technologies in a field of water treatment. The potential advantages of a FO process are lower energy consumption, and higher fouling reversibility compared to other membrane-based desalting technologies, e.g., reverse osmosis and nanofiltration, due to low working pressure. Despite high fouling reversibility, membrane fouling can be still a major obstacle in the FO process. Thus, the employment of spacers can help in enhancing water flux and minimizing membrane fouling. However, the current design of spacers has a potential problem related to spacer fouling, thereby deteriorating the FO process. Therefore, the spacers were examined with the different designs (i.e., hole-type and twisted spacers) fabricated via a 3D-printer for the treatment of shale gas produced water (SGPW). To evaluate the performance of the spacers, either synthetic SGPW or Milli-Q water as feed solution (FS) and different concentration of sodium chloride as a draw solution (DS) were employed. Water flux, reverse solute flux (RSF) and reverse solute flux selectivity (RSFS) were firstly measured with increasing DS concentration with Milli-Q water as FS and a 1-hole spacer exhibited the highest water flux. When increasing FS concentration to 0.3 M NaCl, hole-type spacers exhibited higher water flux than twisted spacers. Therefore, 0-hole and hole-type spacers were selected for SGPW treatment. During SGPW treatment, severe flux decline was observed with all experiments due to the formation of BaSO4 scaling. Flux decline of 1- hole spacers was slightly severer than 0-hole. This might be because scales were broken by high shear force and more covered the membrane surface as shown in SEM images. However, interestingly, hole-type spacers showed no change of pressure drop during SGPW treatment while the pressure drop of the 0-hole spacer increased. Holes of spacers can prevent the accumulation of foulants on the spacer surface, thereby resulting in no change of pressure drop. Physical cleaning with no spacer and the 0-hole spacer showed less than 95% cleaning efficiency while hole-type spacers could enhance the cleaning efficiency and achieve 100%. This might be because the micro-jet induced by holes of the spacer can more readily destroy and remove foulants on the surface.

Produced water is a major waste produced from oil and natural gas wells in the state of Texas. This water could be a possible source of new fresh water to meet the growing demands of the state after treatment and purification. This thesis describes a research project that evaluated the treatment of brine generated in oil fields (produced water) with ultrafiltration membranes. The characteristics of various ultrafiltration membranes for oil and suspended solids removal from produced water were studied to test whether they could be used in a pretreatment method. The research measured the effect of pressure and flow rate on performance of three commercially available membranes for treatment of oily produced water. Oil and suspended solids removal were measured by using turbidity and oil in water measurements taken periodically. The study also analyzed the flux through the membrane and any effect it had on membrane performance. The research showed that an ultrafiltration membrane provided turbidity removal of over 99% and oil removal of 78% for the produced water samples. The results indicated that the ultrafiltration membranes would be useful as one of the first steps in purifying the water. Membrane cleaning of produced water-fouled membranes by micellar solutions was investigated. A neutral pH and ambient temperature micelle solution for effective cleaning of oily water-fouled membranes was developed and studied. The performance of cleaning solutions on ultrafiltration membranes was investigated on laboratory size membrane testing equipment. Different micro emulsion solutions were studied to evaluate the effect of solution properties on cleaning performance. Three types of multiple membranes were studied, each having the same polyvinylidene fluoride (PVDF) material but with different nominal separation or flux characteristics. The data showed that the use of a micelle solution to clean the produced water-fouled membranes was a feasible and effective method. The study showed with further adjustment of the micelle solution the cleaning effectiveness could be optimized to provide double the effectiveness of current industry methods for membranes fouled by produced water.

According to the Texas Railroad Commission (TRC), ????over 250 billion gallons of produced water is taken out of Texas Soil every year, and more than 35% of this water is not currently fit to use.?? Therefore, it can be assumed that domestically and globally, the petroleum industries challenge has been to develop a high-tech and cost effective method to purify the large volumes of oilfield brines and produced water. Currently, most of the produced water requires several pre- and post- treatment methods to aide in reducing fouling of membranes, separation of components, increasing influent and effluent quality, and preventing unwanted work stoppage during the desalination process. As a result, the pre- and post- treatment conditioning of the produced water affects the economics and scale-up (i.e. residence times, absorption capacity, etc??) of the varying processes parameters. Therefore, this research focuses on developing an economic analysis and determining the adsorption capacity of an organoclay system to remove oil.

Produced water is a major waste produced from oil and natural gas wells in the state of Texas. This water could be a possible source of new fresh water to meet the growing demands of the state after treatment and purification. This thesis describes a research project that evaluated the treatment of brine generated in oil fields (produced water) with ultrafiltration membranes. The characteristics of various ultrafiltration membranes for oil and suspended solids removal from produced water were studied to test whether they could be used in a pretreatment method. The research measured the effect of pressure and flow rate on performance of three commercially available membranes for treatment of oily produced water. Oil and suspended solids removal were measured by using turbidity and oil in water measurements taken periodically. The study also analyzed the flux through the membrane and any effect it had on membrane performance. The research showed that an ultrafiltration membrane provided turbidity removal of over 99% and oil removal of 78% for the produced water samples. The results indicated that the ultrafiltration membranes would be useful as one of the first steps in purifying the water. Membrane cleaning of produced water-fouled membranes by micellar solutions was investigated. A neutral pH and ambient temperature micelle solution for effective cleaning of oily water-fouled membranes was developed and studied. The performance of cleaning solutions on ultrafiltration membranes was investigated on laboratory size membrane testing equipment. Different micro emulsion solutions were studied to evaluate the effect of solution properties on cleaning performance. Three types of multiple membranes were studied, each having the same polyvinylidene fluoride (PVDF) material but with different nominal separation or flux characteristics. The data showed that the use of a micelle solution to clean the produced water-fouled membranes was a feasible and effective method. The study showed with further adjustment of the micelle solution the cleaning effectiveness could be optimized to provide double the effectiveness of current industry methods for membranes fouled by produced water.

Mercury (Hg) is distributed globally through atmospheric transport. The broad range of environmental conditions will lead to various possible speciation of mercury, which will ultimately affect the toxicity and transport of mercury. Hg toxicity, transport and speciation have been widely studied. However, information about effects of Hg speciation on its environmental behavior in unsaturated porous media and on its removal from wastewater stream is still limited. The present work contributes towards understanding the impact of Hg speciation on both the transport of Hg species in unsaturated porous media (e.g., surface soil) and removal of Hg species in wastewater streams. This knowledge is necessary to assess the possible environmental risks of Hg in the environment, where different Hg species can exist and have different properties and impacts on water quality and ecosystems. The first objective of this research was to determine the effect of Hg speciation on its retention in partially saturated soils. The retention of Hg species in model porous media and in real soil was assessed in column breakthrough experiments. Deposition (retention) rates for each Hg species were calculated to evaluate the influence of Hg speciation, porous medium composition and influent solution on the mobility of Hg species in porous media. This study provided information about the relative retention of each Hg species in soils, and identified natural-organic-matter-bound Hg as the most mobile Hg species and that with the greatest potential for vertical migration to groundwater. The second objective of this research was to determine how Hg speciation affects its ability to be removed from water via adsorption by activated carbon and organoclay. The effects of Hg speciation, water quality parameters and adsorbent type on the removal of Hg were compared to explore the potential removal efficacy and mechanism. The result indicated Hg removal efficacy was influenced by Hg speciation differently depending on the solution conditions. Therefore, using total dissolved Hg(II) to predict Hg removal efficacy may not provide a reliable estimate of adsorption. Organoclay was shown to have a highly reactive surface and the highest adsorption capacity per unit specific surface area among the tested adsorbents. The third objective was to determine the Hg speciation in produced water from an oil production well, and to study the influence of Hg speciation on its removal from produced water by adsorbents. Mercury species in a produced water sample were identified as mainly particulate species and hydrophobic species. The removal of the amended Hg species in produced water was measured to evaluate the impact of Hg speciation on its removal. This study showed that produced water composition affected Hg speciation and formed hydrophobic Hg was more difficult to remove than initially added hydrophilic Hg species in produced water.

Microfiltration is one of the most important processes in membrane sciences that can be used for separating drops/particles above 1 ??m. Depth microfiltration membranes retain drops/particles inside the surface of the membrane, the process is expensive and membranes quickly become fouled. On the other hand, surface microfiltration membranes stop drops/particles on the surface of the membrane and the process is less fouling. Higher permeate flux and lower trans-membrane pressure is obtained with a shear enhanced microfiltration technique. Production of specific size of drops and stability of the drops are very important in testing the microfiltration of crude oil drops/water emulsions. Oil drops from 1-15 ??m were produced with a food blender, operated at its highest speed for the duration of 12 mins. In addition, vegetable oil drops were stabilised with 1% polyvinyl alcohol (PVA), Tween 20 and gum Arabic, stability was assessed on the basis of consistency in the size distribution and number of drops in each sample analysed at 30 mins interval. A slotted pore Nickel membrane with the slot width and slot length of 4 and 400 ??m respectively has been used in the filtration experiments. The slot width to the slot length ratio (aspect ratio) of the used membrane is 100. Vibrating the membrane at various frequencies created shear rates of different intensities on the surface of the membrane. Membrane with a tubular configuration is preferred over the flat sheet because it is easy to control in-case of membrane oscillations both at lab and industrial scale. Besides this, a tubular membrane configuration provides a smaller footprint as compared to the flat sheet. The influence of applied shear rate on slots/pore blocking has been studied. Applying shear rate to the membrane reduced the blocking of the slots of the membrane; and reduction of slots blocking is a function of the applied shear rate. At higher shear rate, lower blocking of the slots of the membrane was verified by obtaining lower trans-membrane pressure for constant rate filtration. The experiments are in reasonable agreement with the theoretical blocking model. Divergence of the experimental data from the theory may be due to involvement of deforming drops in the process. During microfiltration of oil drops, the drops deform when passing through the slots or pores of the membrane. Different surfactants provided different interfacial tensions between the oil and water interface. The influence of interfacial tension on deformation of drops through the slots was studied. The higher the interfacial tension then the lower would be the deformation of drops through the slots. A mathematical model was developed based on static and drag forces acting on the drops while passing the membrane. The model predicts 100% cut-off of drops through the membrane. Satisfactory agreement of the model with the experiments shows that the concept of static and drag force can be successfully applied to the filtration of deformable drops through the slotted pore membranes. Due to the applied shear rate, inertial lift migration velocities of the drops away from the surface of the membrane were created. Inertial lift velocities are linear functions of the applied shear rate. A mathematical model was modified based on inertial lift migration velocities. The critical radius of the drops is the one above which drops cannot pass through the surface of the membrane into the permeate due to the applied shear rate and back transport. The model is used as a starting point and is an acceptable agreement with the experiment. The model can be used to predict the 100% cut-off value for oil drops filtration and a linear fit between this value and the origin on a graph of grade (or rejection) efficiency and drop size to slot width ratio was used to predict the total concentration of dispersed oil left after filtration. Hence, it is shown how it is possible to predict oil discharge concentrations when using slotted filters.

Synthetic membranes have a high separation efficiency, small footprint, low energy consumption and ease of operation, making them an attractive alternative to traditional separation operations. For this reason, membranes have been extensively studied for the treatment and recycling of bitumen-containing wastewaters. Such wastewaters include petroleum produced water, residual pipeline cleaning solutions and contaminated water from oil spills. Ceramic membranes are preferred in these applications over polymeric membranes because they are highly resistant to solvents and can be operated at high temperatures over a wide range of pH. Fine clays and silicates, coated with bitumen, are significant foulants for membrane filtration systems. These foulants possess acidic, basic and amphoteric groups, leading to the presence of both positive and negative surface charges. Ceramic membranes in aqueous media have a pH dependent surface charge. It was hypothesized that these surface charges are responsible for the high fouling of ceramic membranes that is observed when treating wastewaters containing bituminous fines. The overall objective of this research was to reduce fouling and increase the lifetime of ceramic membranes in treating oil sands produced water; an example of a wastewater containing bituminous fines. This goal was achieved through the surface modification of the ceramic membrane’s selective layer, as well as by the implementation of a novel in-place steam regeneration technique. All membrane filtration tests were performed with field samples of oil sands produced water that were supplied to CanmetMINING (NRCan) by three Canadian oil sands companies. Organosilanes are silicon-based monomers that can possess a wide array of chemical functionality due to their organic moieties. They are capable of reacting with oxide surfaces, and have seen extensive use as surface modification agents for ceramic membranes in various applications. To maintain desirable hydrophilic properties without surface charges, highly hydrophilic and non-ionic polyethylene oxide (PEO) based organosilanes were identified. These PEO-silanes were then used to modify ceramic membranes of several different selective layer materials, and the thermal stability of the silane layer was studied using FTIR, SEM, zeta potential and contact angle measurements. The modification procedure with PEO-silanes was first applied to lab-scale membrane disks, and subsequently to commercial scale multilumen membrane tubes that were tested in a pilot-scale system at CanmetMINING. Results obtained from both sets of experiments were promising and demonstrate that ceramic membranes can be surface modified in a way that successfully renders them fouling resistant to the bituminous fines present in these wastewaters. Upon surface modification, foulants were more readily released from the membrane surface, resulting in an enhanced flux and separation performance. A novel steam regeneration technique was also applied as a means of bituminous fouling alleviation. This technique was tested in the CanmetMINING pilot-scale system and consisted of periodically injecting steam into the membrane lumen feed channels during operation. Direct steam injection rapidly heated foulant cake layers, and water droplets in the saturated steam caused surface abrasions that ultimately resulted in the scouring of bitumen away from the membrane surface. Membrane fluxes when steam regeneration was active were up to 4 times higher when compared to tests where only traditional permeate backflushing was used. The fouling remediation techniques developed in this work have broad potential applicability in ceramic membrane filtration systems aimed at treating all wastewaters containing bituminous compounds, such as process waters in general and contaminated water from oil spills.

Unconventional natural gas extraction from the Marcellus Shale requires millions of gallons of water to fracture shale and release natural gas from the formation. This process produces water with high levels of total dissolved solids (TDS); and, efforts to recycle these fluids has stimulated microbial growth in produced water. The objective of this study was to analyze the ionic composition of and characterize microorganisms from Marcellus produced water samples. A semi-synthetic culture medium was designed with high TDS to enrich for halophilic microbes, which yielded robust cultures that were able to grow over a wide range of salinities. DNA extracted from aerobic cultures was used for 16s rDNA clone libraries and Automated Ribosomal Intergenic Spacer Analysis (ARISA). ARISA and 16S gene sequencing revealed differences in bacterial composition between Marcellus and freshwater samples. Sequencing of 16S gene indicated the presence of Halomonas, Thalassospira and other genera related to halophilic and petroleum degrading species. / Bayer School of Natural and Environmental Sciences / Environmental Science and Management (ESM) / MS / Thesis