Electrochlorination Fights Invasive Species Migration

Evoqua Water Technologies announces new ballast water management solution passes brackish testing.

Invasive species can move from one ecosystem to another in any number of ways and can cause serious damage to the habitats unlucky enough to host them.

Asian carp, specifically silver carp, are notable for leaping out of water in response to approaching boats. Fisherman and kayakers often suffer injuries from the fish, which weigh up to 45 kg (100 lbs.) and can sometimes jump eight to 10 feet in the air. Propagating wildly, they and other types of carp feed on local plankton, larval fish and native mussels, sometimes to the point of endangerment.

Invasive Phragmites, otherwise known as European common reed, have caused damage to North American biodiversity for decades and is most common in wetlands and beaches. This plant spreads rapidly, outcompeting local species by releasing toxins from its roots into the soil, killing surrounding plants.

One paper (Pimental et al. 2005) estimates that the economic impact of invasive species such as these equal $120 billion in damages every year in the U.S. alone.

One way in which smaller aquatic invasive species can travel large distances is by hitching a ride in a ship’s ballast water.

How BWMS and the SeaCURE System Work

Evoqua Water Technologies recently announced their success in completing low salinity (brackish) water testing with their SeaCURE system, as a ballast water management solution (BWMS).

Evoqua's SeaCURE system is the first to complete USCG protocol tests designed to safely protect the environment and economies from invasive species.

Evoqua’s SeaCURE system is the first to complete USCG protocol tests designed to safely protect the environment and economies from invasive species.

BWMS systems are designed to protect environments from invasive aquatic species by filtering a ship’s ballast water.

Many types of BWMS systems exist, and each employ different ways of killing or neutralizing organisms caught in ballast water. Often two or even three systems are used together.

For example, a physical separation system can be used to filter marine organisms and suspend solid materials from ballast water using sedimentation or surface filtration. Suspended waste water can be discharged or treated further with chemical disinfectants, for example.

Biocides can remove invasive organisms otherwise not caught in surface filtration, but must be degradable or removable to prevent discharged water from becoming toxic.

Evoqua’s SeaCure electrochlorination system works by essentially creating bleach in the ballast water.

“The heart of the system is the electrolytic cells that convert the salt in sea water into the active substance, sodium hypochlorite,” Evoqua’s website reads. Sodium hypochlorite is commonly used as a bleaching agent and disinfectant.

Use and Further Testing

The SeaCURE system is designed for use by gas carriers, tankers, bulk carriers and container vessels with higher ballast water flow rates ranging from 500 to 4,000 cubic meters per hour. Multiple units can be used for higher flow rates.

Designed to save energy and reduce operating costs, variations in demand are considered in delivering biocides only at the necessary dosage for successful ballast treatment. The SeaCURE systems technology is based off of Evoqua’s previous Chloropac marine growth prevention system.

Evoqua’s SeaCURE system is the first electrochlorination system to receive Alternate Management Systems (AMS) acceptance for all three salinities, which includes fresh, brackish and full saline water.

AMS acceptance is a temporary designation. This allows vessels operating in US waters to use BWMS systems to manage ballast water discharges while undergoing United States Coast Guard (USCG) Type Approval testing.

Brackish trials are the first of three test phases required for full approval of BWMS systems by the USCG. The SeaCURE is now moving on to fresh water testing, with trials at sea planned for later in 2015.

Testing for the SeaCURE BWMS system is performed at the Marine Environmental Resource Center in Baltimore, Maryland. Testing conditions replicate environments in which the system will be used.

To learn more about Evoqua’s SeaCURE BWMS system, visit evoqua.com.