State proposes new wastewater mixing zones for Pacific Seafood's Kodiak plants

The Alaska Department of Environmental Conservation on Monday proposed setting new zones in Kodiak's Near Island Channel where wastewater from two Pacific Seafood processing plants could dilute before it has to meet state water quality standards, according to a public notice.

The zones are called mixing zones. Inside them, the water near the end of each discharge pipe can carry more of certain pollutants than state standards allow while it mixes with seawater. At the edge of each zone, the standards have to be met, and the zone can't create toxic conditions, according to DEC's permit fact sheet.

The proposal covers the company's Near Island and Star of Kodiak plants, which discharge through two pipes into the channel. At both, the zones would cover ammonia and chlorine. At one pipe, the zone would also cover warmer water.

Ammonia can come from natural decay, leaks in refrigeration systems and ammonia-based cleaning products, the fact sheet says. Chlorine is used as a disinfectant, and discharged cooling and boiler water can raise water temperatures. The wastewater itself carries shell, bone, skin, scales and blood, and the permit requires seafood waste to be screened down to 1 millimeter or smaller before it's released.

The larger zone would stretch about 110 meters long and 70 meters wide around the pipe, about the length of a football field, end zones included. The smaller one would be 36 meters by 11 meters.

Kodiak's five onshore seafood processing plants and one plant that turns waste into byproducts operate under a shared state permit that took effect in June. It allows mixing zones set for individual plants, but it bars piles of seafood waste on the seafloor.

DEC says it has tentatively decided to make the change. It is taking public comment through Dec. 2 on its public notice site.