North Little Rock Electric Department Relies On Oil Skimming For Hydroelectric Generation Plant

Known only as opposite Little Rock until the Civil War, North Little Rock grew as a crossroads that linked river and overland traffic. Today, it is a thriving community of more than 60,000. In 1988, North Little Rock constructed its own hydroelectric cogeneration plant on the Arkansas River. Its two generators are capable of producing 42 megawatts of power at peak capacity, enabling the city to furnish approximately 20 percent of its own fixed-cost fuel electricity. This puts North Little Rock in the enviable position of reasonably priced utilities. It also creates another opportunity for the North Little Rock Electric Department to exhibit its strong environmental stewardship practices.

Any potential oil leaks in the hydro plant must be contained. Oil in the river is not tolerated.

So it is no surprise that the plant has a way to keep potential oil leaks from getting into the river and remove oil from water: oil skimming.

Oil skimmers make use of the inherent differences between oil and water. These physical characteristics allow the skimming media to attract oil from the waters surface. For their oil skimming equipment North Little Rock relies oil skimmers from the Abanaki Corporation.

The Abanaki Corporation is a world leader in oil skimming solutions, serving industries as diverse as iron and steel, wastewater, paper, food processing, automotive, environmental remediation and recycling. Years ago, the North Little Rock Electric Department installed a popular Abanaki belt skimmer as a dependable and effective means of removing oil from water that outlets from the plant back into the Arkansas River.

The most widely used Abanaki skimmer, the Oil Grabber Model 8, is designed for easy mounting in a small footprint. The plant workers like the design of the Abanaki belt oil skimmer because of the easy maintenance. Only a small area in a tank or sump is required, making it ideal for an application like that required by the North Little Rock Electric Department.

North Little Rock Electric Department has been using an Abanaki Oil Grabber for over 10 years. Before Abanaki, the plant used a floating oil skimmer that didnt work very well at all.

The Oil Grabber Model 8 is situated in a retention sump that catches oil leaks from any hydraulics located throughout the hydro electric plant always a distinct risk in a facility whose water turbines represent the single largest gear in operation anywhere in the world.

A belt, operating on a motor and pulley system, runs through the water. After traveling over the head pulley, the belt passes through tandem wiper blades where oil is scraped off both sides of the belt and collected into a container.

After the skimming stage, the water is pumped into holding tanks and processed through a dedicated oil water separator before the water can be released back into the river. The plant staff acknowledges that the final filtering stage has gotten a break since the Abanaki oil skimmer was installed.

Before Abanaki, the oil water separator had to work hard to clean the water prior to being released into the river. The Abanaki oil skimmer removes the majority of the oil from the sump before it is processed further, so the separator doesnt have to run as long and doesnt need to be cleaned as often.

An environmental inspector visits the plant regularly to take water samples of the water discharged back into the Arkansas River; and their water samples always test well.