Document Type

Restricted Campus Only

Publication Date

4-2014

Abstract

Each year, billions of gallons of water are used by the oil and gas industry in a process called hydraulic fracturing. This technique combines chemicals, sand, and other proppants in a water based mixture that is pumped into the well bore at extremely high pressures. The solution usually sits in the well formation for a couple of months until the well begins to flow, allowing salts, oil, grease, and other organic material to interact with the fluid. The solution is therefore rendered contaminated when it returns to the surface, as the total dissolved solids and organic mateiial levels are drastically higher than the ground water maximums set by the Environmental Protection Agency. The industry reuses what water it can on other wells but usually disposes of the remaining amounts by pumping it untreated into the ground, where it is stored indefinitely. While this may be the most economical option for the oil and natural gas industry, it is not the environmentally friendly. We are continuously experiencing droughts on both a domestic and global scale, and it is important that we do everything we can to reduce, recycle, and reuse our most precious resource, water.

We aimed to create a tabletop process that treated used hydraulically fractured water (commonly referred to produced and flowback water) to meet the EPA groundwater standards. The treatment process was expected to purify the water at a rate no less than 0.25 gallons per minute.

We extensively researched various treatment unit operations, as well as typical produced and flowback water compositions to have an idea of what to expect in the water. Once actual water samples were obtained, ICP and IR tests were run to deterntine the amount of total dissolved solids and to give an idea of what organic materials were in the water.

Decontantination was broken into three major categories: pretreatment, desalinization, and organic removal. To pretreat the water, a simple melt spun filter was used. This removed all the larger particles that would cause a finer filter to clog quickly. A base treatment unit was implemented into the design to decrease the salinity, and an acid titration immediately followed to neutralize the solution. Two activated carbon block filters were integrated into the design to remove organic matter. Lastly, a reverse osmosis unit served to remove even more trace amounts of salts and organic materials, refining the water to a more purified state.

When comparing ICP data from our original flowback water and our treatment system permeate, our results showed a large decrease in the amount of total dissolved solids. This value was below the maximum parts per million set by the EPA. While the IR data does not quantify the amount of organics removed, it does show a significant decrease from the original flowback sample. Due to issues with our reverse osmosis pump, the system was unable to treat water at a rate of 0.25. A new pump capable of reaching the necessary pressure was purchased, but was not able to be tested due to our time constraint.

We recommend finding an alternative to the base treatment unit and testing the unit with the new pump. We also recommend implementing a more sophisticated switch panel, complete with digital pressure gauges and power control switches. This would allow the design to be completely operated by one individual.

Comments

Dr. Mahbub Uddin, Advisor

ENGR-4381

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