How to Remove Boron, Benzene from Oil and Gas Produced Water

Although it is sometimes reused for energy purposes, it can also be used for agriculture.[1] However, it must be carefully and properly treated to remove benzene, boron and other contaminants. Every year, wells for oil and gas generate billions of gallons of produced water. Less than 1% of that water is reused today. As a result, many companies are starting to develop ways to decontaminate produced water for agricultural applications.

Why Removing Benzene and Boron Is Important

Produced water contains several types of organic matter, and there are ways to remove most of those substances. Some produced water in certain places may not be reusable, and it is injected into the ground in accordance with State and Local guidelines. The water's quantity, chemistry, cost of treatment and other factors determine whether it is reused or disposed. Produced water that can be reused with treatment for agricultural purposes must have the majority of boron and benzene removed.

Benzene

Benzene is a carcinogen that may increase risks of developing several types of cancer in humans. As a product of crude oil, it is a common substance found in produced water. Additionally, benzene in produced water may inhibit photosynthesis in plants. This makes it a problematic substance for irrigation. Benzene often exists with other dissolved volatile aromatic hydrocarbons. They are toluene, ethylbenzene, and xylene, and the combination is called BTEX.

Boron

When it comes to plants or crops, a small amount of boron facilitates growth. However, produced water tends to have a higher concentration of boron. In larger amounts, boron in irrigation water is toxic to plants. It may cause several forms of problems, and those problems can vary in nature depending on the type of crop. For instance, too much boron can stunt growth in wheat or other sensitive crops.

Treatment Processes for Removing Benzene

In addition to existing produced water treatments, researchers are testing new processes and substances to look for more options. Currently, there are several effective methods for removing benzene and other problematic, dissolved compounds from produced water. Before treatment, the water typically contains large and small oil droplets, fine and coarse solid particles and dissolved matter.

Initial Treatment

Storage tanks, strainers and other devices are used at the beginning this phase, which conditions the water. Gas bubbles, large droplets and coarse particles are removed. This may also be called pretreatment. Facilities may use plate pack interceptors, skim tanks and API separators in the main treatment. The first part of the main treatment removes small droplets and particles. In the second part, facilities use centrifuges or other equipment to remove additional smaller particles and droplets.

Secondary Treatment

Facilities use cartridges, filters and other equipment to remove ultra-small particles and droplets. This step is important for removing dissolved aromatic hydrocarbons, such as benzene. At the end of this phase, dispersed hydrocarbons in the produced water should be below 10 mg/l. Advanced treatment technologies are necessary to remove soluble or dissolved organic acids, aromatics and phenolics. Removing dissolved organic compounds may be accomplished through nanofiltration, reverse osmosis, chemicals or another method.

Tertiary Treatment

Special processes, such as gas or steam stripping, are used to create a higher quality of treated water. At the end of this process, the water typically has dispersed hydrocarbons below 5 mg/l. Tertiary treatment is not used in all applications of produced water treatment. However, it is commonly used when a higher standard is required, and there are usually accompanying standards relating to biochemical oxygen demand, heavy metal content and other restriction categories.

Ultimately, the goal of any produced water treatment process is to remove oil, salt, gas, suspended solids, heavy metals, organic compounds and radionuclides. It may also be disinfected.

Treatment Processes for Removing Boron

Because of boron's dissociation and molecular weight, many standard wastewater treatments do not remove it. Its nonionic form in an aqueous environment makes it difficult to selectively remove. There are several methods that may be used for removing boron from water. These are three methods that are commonly found in research.

Reverse Osmosis

With oilfield water, reverse osmosis may not always be ideal. It is limited to water with a salinity of about 100,000 ppm. To properly clean the water with a higher salinity, the system should feature multiple passes. When there is a neutral Ph, RO is not as useful for removing boron. Improved boron rejection can only be achieved with a higher Ph. Pretreatment steps, Ph modification or other requirements may be necessary if RO is used to remove boron from produced water for reuse.

Electrocoagulation

For those who research water treatment options for use in agriculture, this is a common treatment that appears in search results. Electrocoagulation is a form of water recycling for produced water. It uses an electric current to target and destabilize contaminants that are suspended in fluid. Although there are several companies working to develop or promote the use of electrocoagulation, it does not target boron specifically. However, literature suggests that it may be up to 95% effective.

Chemical Removal

There are multiple types of chemicals that may be used to reduce boron levels in produced water. Multiple studies exist that suggest different types of chemicals to remove boron. A study involving a patent for a method using polyvinyl alcohol exists but requires additional research for its effectiveness and cost efficiency.

Calcium hydroxide is a substance that may be used to remove boron with certain methods. In one study, it was used in a precipitation method along with sulfuric acid added to it. Under a specific temperature range, the mixture increased boron removal. The same research report showed that calcium carbonate was used with solutions of magnesium chloride, sodium chloride and boric acid in different ratios. However, the magnesium combination showed the greatest efficacy in boron rejection.

Using Produced Water in Agriculture

As global demands for fuels continue to rise, the amount of produced water is projected to increase significantly. Water scarcity has been a common topic on news headlines around the world, and it is leaving more decision makers with a new dilemma to plan for as they look to the future. Part of developing a future-focused business sustainability strategy is addressing important water needs now. As more consumers demand social responsibility from merchants and suppliers, it is critical to make responsible water use a top priority. CEOs and business owners in agriculture can benefit from learning more about using produced water from oil and gas extraction that has been properly treated for reuse.

Magical Chemicals treatment process includes proper pretreatment and the use of special methods and substances to remove boron, benzene and other harmful compounds from produced water, making it safer to use for agricultural settings. We offer solutions for a variety of needs.

At Magical Chemicals, we are working to solve these problems. To work with us visit our contact page.