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There is no single best way to remove benzene and BTEX from wastewater. The right method depends on concentration, flow, the other contaminants present and what the plant wants to do with the recovered hydrocarbons.

Air or Steam Stripping

Moves volatile compounds from the water into a gas stream. Effective for volatile compounds, but the off-gas must then be captured or treated, so it can shift the problem to air.

Adsorption

Passes water over a media that holds the BTEX. Works well at lower concentrations and for polishing to tight specifications. The media needs replacement or regeneration.

Solvent Extraction and Recovery

Pulls hydrocarbons out of the water and recovers them. This suits streams where recovered material has fuel value, and avoids sending hazardous waste for disposal. Power Energy’s VC SORB process works in this direction, converting BTEX, VOCs and chlorinated hydrocarbons into reusable fuel.

Biological Treatment

Bacteria break down BTEX in a biological plant. It is economical for steady, moderate loads, but it is sensitive to shocks, and spikes of toxic compounds can upset it.

How to Choose

• Characterize the stream, including concentrations and other contaminants
• Check the discharge specification you must meet
• Compare options on performance, reliability, economics and life cycle cost
• Pilot test where the stream is unusual

Power Energy runs this process for plants in Saudi Arabia and the GCC. See benzene and BTEX removal and read where benzene comes from in refinery wastewater.

Talk to Power Energy

Send us your stream details, contaminants and flow rate. Call or WhatsApp +966 56 278 9535 or email sales@powerenergy.com.co.

Spent caustic is a sodium hydroxide solution that has been used up in washing acidic components out of hydrocarbon streams. It is a common waste stream in refineries and petrochemical plants, and it needs proper handling.

Where It Comes From

Caustic scrubbers remove hydrogen sulfide, mercaptans and carbon dioxide from gas and liquid streams such as LPG, gasoline and ethylene. When the caustic is exhausted, it is drawn off as spent caustic.

What It Contains

• Sulfides and mercaptans, which give it a strong odor
• Phenols and organic acids, depending on the source
• Dissolved hydrocarbons, sometimes including BTEX
• High COD and high alkalinity

How It Is Treated

Treatment depends on the type of spent caustic and the plant’s goal. Typical routes include removing hydrocarbons and BTEX first, neutralizing and oxidizing the sulfur compounds, and recovering caustic or salts where it is worthwhile. In petrochemical wastewater, recovering caustic and useful salts reduces how much has to be treated or disposed of. Hauling it off site is costly and adds transport risk, so on-site treatment is often preferred.

Using Mobile Units

Rental skid-mounted units let plants treat spent caustic without capital spending, for example during turnarounds or upsets. Power Energy supplies these as rental, rent-to-own or operated units. See spent caustic treatment and mobile treatment units.

Talk to Power Energy

Send us your stream details, contaminants and flow rate. Call or WhatsApp +966 56 278 9535 or email sales@powerenergy.com.co.

Benzene is one of the most closely controlled contaminants in refinery and petrochemical wastewater. Knowing where it enters the water is the first step to removing it. BTEX, the group of benzene, toluene, ethylbenzene and xylene, tends to travel together.

Main Sources

• Crude desalters. Water washed out of crude carries dissolved aromatics.
• Process condensate and stripper bottoms. Steam that contacts hydrocarbons leaves with dissolved BTEX.
• Aromatics and olefins units. Plants that make or handle benzene, styrene or similar products produce wastewater with the same compounds.
• Tank bottoms and drains. Water drawn from storage tanks often carries free and dissolved hydrocarbons.
• Turnaround and shutdown water. Cleaning, flushing and hydrotest water picks up hydrocarbons from equipment.
• Spent caustic. Caustic scrubbers can concentrate BTEX along with sulfides and phenols. See spent caustic treatment.

Why It Matters

Benzene is toxic and a known human carcinogen. It also volatilizes from open water surfaces, so untreated wastewater becomes an air emission problem as well. Dissolved and emulsified BTEX can pass through ordinary oil separation, which only removes free oil.

What Plants Do About It

The usual route is to characterize the stream first, then choose a removal method that suits the concentration and flow. Options are compared in our comparison of benzene removal options. Power Energy offers benzene and BTEX removal with rental, rent-to-own or operated skids, plus VOC removal and emission control.

Talk to Power Energy

Send us your stream details, contaminants and flow rate. Call or WhatsApp +966 56 278 9535 or email sales@powerenergy.com.co.

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