Modern wastewater treatment for Anchorage, Alaska

Electrolytic Technologies helped revolutionize water and wastewater treatment plants for the Anchorage Water & Wastewater Utility.

Previously, chlorine gas served as the longtime disinfectant across facilities. To service the facilities, 2,000-pound chlorine cylinders had to be barged in and transported by truck across the city to the primary treatment plant. Amid increased safety and risk management concerns for the Anchorage community, the utility sought to change direction and adopt alternative disinfectants.

For the Asplund Wastewater Treatment Facility, Alaska’s largest wastewater plant, Electrolytic Technologies provided an award-winning wastewater disinfection solution.

The utility’s transition began in 2000 with the on-site implementation of Severn Trent Clortec systems, with an 0.8-percent sodium hypochlorite solution, at the two water treatment plants. Asplund then converted facilities at two smaller wastewater treatment plants—the Eagle River community north of Anchorage adopted UV disinfection, while the Gridwood facility south of Anchorage adopted a 12.5-percent hypochlorite solution.

For Aplund’s primary treatment plant, the utility installed Electrolytic Technologies’ Klorigen hypochlorite generation system—a system that earned a Qualified Anti-Terrorism Technology designation from the U.S. Department of Homeland Security. After evaluating UV, ozone and hypochlorite in the area, the utility determined that a 12.5-percent hypochlorite solution would require a smaller building footprint and more efficient energy, water and salt consumption.

The system was custom-designed to accommodate the utility’s needs, then installed in two phases. The process in its entirety included the installation of storage tanks, pumps, and the feed system for the hypochlorite disinfection, as well as the installation of generation equipment.

A unique feature of the new system is a mechanism that splits the generated chlorine gas between the point of application and the hypochlorite conversion skid. Typically, these systems produce more gas than there is caustic to recombine, requiring supplemental caustic to complete the conversion of chlorine gas to sodium hypochlorite. Asplund’s new system is a hybrid one, with an ion-selective membrane that distributes the salt to one side and chlorine gas to the other. The system allows the utility to account for excess chlorine gas in the disinfection process and vary the flow of hypochlorite to meet requirements.

To implement the system, familiarize with the technology, and learn the operational safety precautions, Anchorage Water & Wastewater Utility personnel worked closely with the installation contractor, on-site engineer, and vendor.

Through the support of Electrolytic Technologies, the Anchorage Water & Wastewater Utility has become a leader of community safety and clean-water technology. To view the full article, please visit: Alaska Planta Addresses Community Safety With Upgrade.