How to Treat Produced Water from the Oil and Gas Industry for Municipalities

In the United States, the regulations differ in the type of sampling required due to the quality of wastewater and how it's used. The physical and chemical properties of water differ based on geographical location; therefore, produced water generally has to have contaminants before it's released in the sewer system or sent for further refinement.

Since produced water contains salts, organic compounds, radioactive materials, chemical additives, and other elements local municipalities require energy companies to treat produced water according to minimum quality standards and the likely use. As a result, the treatment of produced water from the oil and gas industry must meet applicable permit rules. In any case, it's also the liability of oil and gas companies to properly treat, transport, and dispose of the produced water.

Before treating produced water for discharge to wastewater treatment plants, oil and gas companies must apply for appropriate permits, if needed. These permits are either issued by the state or local municipalities. 

It's important to understand the underlying regulatory framework because it offers guidance to oil and gas operators regarding the type of setup necessary before they can release produced water to the public system.Based on the chemical composition of the produced water, energy companies may need to set up multiple individual unit processes to treat contaminants in produced water.

Here is an overview two technologies for the treatment of produced water:

• Organic and Particulate removal
• Disinfection

Based on permit limitations, operators may need at least one or more technologies to treat produced water before discharging it to the municipal network.

Organic and Particulate Removal

Organic and particulate removal technologies are the types of pretreatment techniques.They include biological aerated filter, hydrocyclone, dissolved air flotation, UV disinfection, polymeric filtration, ceramic membrane, adsorption, media filtration, settling ponds, air stripping, surfactant modified zeolites, constructed, wetlands, and granular activated carbon. The size and the type of contaminants removed by each process differs widely.

Irrespective of the quality of water, these pre-treatment techniques have an overall process recovery rate of more than 98%. Almost all of these are actively used by oil & gas companies due to their proven reliability. Besides offering reliability, pre-treatment units can withstand harsh conditions without overly relying on any single component. If a failure occurs, it's relatively easy to fix any issues without disrupting ongoing operations.

The only downside of the type of technique is the high cost associated with setting up certain units. For instance, popular pre-treatment processes such as hydroclone, centrifuge, API gravity separator, and corrugated plate separator are relatively expansive despite the high level of reliability and robustness. As a result, these are preferred by operators who require easy setup and that do not need to remove heavy metals.

Disinfection

Disinfection technologies can be used to kill large amounts of bacteria in the processed water. Some US states require oil & gas facilities to disinfect the water before carbon treatment. Accordingly, disinfection may be required if operators decide to use low-cost emerging pre-treatment technologies such as granular activated carbon.

During the process, the water is pumped into a UV reactor, which has numerous UV lamps that help disinfect the water. Depending on the required level of disinfection, pathogens are exposed for a predetermined period of time.

Disinfecting using the UV process does not leave any residue. Therefore, adding chlorine or chloramine is required to treat the processed water.

Treatment Before Discharge

Treating produced water from the oil and gas industry for discharge to municipal network requires a proper understanding of the process. Anyone interested in the topic should get pertinent permits required to do so. 

Once the operator has a clear understanding of the local requirements of processed water discharge to the municipal network, the next step is to select a proper treatment plant that can help fulfill those requirements. As evident from the discussion, not every plant is designed to remove contaminants. Hence, it's important to use a treatment method that can efficiently remove contaminated particles. As an additional step, the operator may need to integrate separate units to help remove one or more contaminations.

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