Case Study

Electrocoagulation Provides Economical Solution For Produced Water To Oil & Gas Companies

Source: Genesis Water Technologies

Oil and natural gas are considered valuable resources all across the globe. The number of products made from these two materials is impressive and our lives would be very different without them. Production of these products begins with locating the underground sources of crude oil. These deep well sources are then mined to extract the oil and gas materials. Afterward, these raw materials are sent to refineries to be converted into the petrochemical and gas products that we use nearly every day. Therefore, produced water treatment & management is an integral part of oil & gas company operations.

At certain points in the process of oil and gas production, water is used in some capacity. Those particular points are during extraction and refinement, and each of them uses significant amounts of water. During extraction, water is pumped beneath the oil deposits to push it towards the surface, though there is also water that already exists in those pockets. Refinement processes use the bulk of their water in cooling towers, but it is also used heavily in the form of steam.

Extraction and refinement result in heavily contaminated produced water and wastewater respectively. Environmental regulations demand that the water is treated before it is disposed of, though it may also be reused.

There are many treatment options for produced water and refinery wastewater to ensure that it is safe enough to discharge or reuse. However, any of those methods can be costly by themselves and potentially inefficient. Therefore, requiring additional units and treatments to ensure regulations are met.

Luckily, electrocoagulation (EC) has the potential to offer an economical solution to oil and gas companies as part of a produced water treatment or refinery wastewater treatment solution.

However, for the sake of brevity, here we’ll just discuss produced water treatment & management.

If you would like to know more about how EC can benefit refinery wastewater, check out this article.

Produced Water Contaminants

Pollutants in produced water mainly come from the crude oil and gas itself, the surrounding sediment, or chemicals added to water during extraction operations. Such contaminants include:

  • Salts

  • Oil and Grease

  • Naturally Occurring Radioactive Material

  • Hydrocarbons

  • Microorganisms, Bacteria, and Viruses

  • Heavy Metals

  • Organic Compounds

  • Corrosion Inhibitors, Scale Inhibitors, Emulsion Breakers, etc.

  • Hardness

  • Sulfur or Hydrogen Sulfide

Why Produced Water Needs to be Treated

There are a number of problems that can arise within the environment because of pollutants such as these. Oil rigs out on the ocean are especially prone to causing environmental harm because they have a direct effect on marine habitats. Produced water from land drilling is often re-injected back underground, so pollutants can affect groundwater sources.

Salts for instance, while they may not have much effect on marine habitats, can negatively effect the growth of land-based plant life by inhibiting their ability to absorb nutrients and water. Oil and grease can have similar results on both freshwater and saltwater plants while also coating the hair and feathers of mammals and birds. This leaves these animals susceptible to overheating and hypothermia.

Fish can experience inhibited growth rates and their eggs can be wiped out. Hydrocarbons are known carcinogens and have numerous health effects on plant and animal life. Bacteria and viruses spread disease and heavy metals are toxic in high enough doses.

Why EC is an economical choice for produced water treatment

Electrocoagulation has grown in its recognition for its efficient and cost-effective treatment of waste water in many industries, but the oil and gas industry, in particular, is a prime example. EC has many qualities that make it part of an economical solution for oil and gas companies looking to lower their capital and operational costs while increasing the efficiency of their extraction operations.

EC is a very versatile technology. It has the potential to do the job of several different treatments all at once with mid-range results. It can also be optimized for one of many possible contaminants to maximum effect. There have been numerous studies done that validate EC’s ability to remove or reduce contaminants such as emulsified oils, bacteria, organic and inorganic chemicals, heavy metals, hydrogen sulfide and others.

Though, EC does use a consistent draw of power, under proper optimization this power draw can be minimized, making the process use less energy than other treatment options which aids in lower operational costs.

Electrocoagulation units are not complex, and don’t require much in the way of materials for installation or operation, and the materials that are required are relatively inexpensive and easy to acquire. The electrodes, for example, are typically made of aluminum or iron, which are typically readily available.

Again, these units are easy to operate, and operation and maintenance costs are relatively lower as well. Most adjustment with these systems is for pH and current, and those can be done automatically with a PLC setup. Maintenance typically consists of PLC controlled electrode ion transfer, occasional CIP cleaning, and replacing the electrodes when they are too corroded. The rate of electrode corrosion can be slowed with proper maintenance, however.

Sludge disposal can be an issue with other treatment systems, but EC produces lower volumes of nontoxic sludge. This can greatly decrease costs associated with any treatment or disposal of sludge to meet environmental regulations.