Permit Renewal

Overview

Asplund operates under a federal NPDES permit issued by the EPA under Section 301(h) of the Clean Water Act. AWWU has applied to renew that permit. The renewal application is supported by decades of routine monitoring and additional studies completed specifically for the renewal. The EPA has administratively continued Asplund’s current NPDES for many years. AWWU voluntarily submitted its application to renew and update the permit at the end of 2025.

Why is the Current Permit Listed as Expired?

NPDES permits are issued for limited terms. Asplund’s existing permit expired in 2005 but was administratively continued by the EPA, so it remains legally in effect while EPA considers the renewal. AWWU continues to follow the permit’s treatment, monitoring, reporting, and pretreatment requirements.

Beluga whales surfacing in the waters of Cook Inlet, Alaska. The whale's white back and head are visible above the dark blue water, with the rest of the body submerged.

Understanding the NPDES Permit Application Process

Renewing a NPDES permit is a data-intensive process. It requires ongoing monitoring, years of data collection, scientific analysis, and extensive documentation to demonstrate that the treatment facility is meeting permit requirements and protecting water quality. The permit includes the following:

Decades of Water Quality Monitoring

AWWU has been monitoring water quality in Cook Inlet since the plant started serving the community as part of its NPDES permit requirements. Water quality parameters are measured daily, weekly, and monthly to confirm that treatment at Asplund continues to meet permit conditions.

AWWU also samples for toxic pollutants, pesticides, and metals twice each year to make sure Asplund meets applicable water quality standards. The results of this monitoring are documented in AWWU’s Monitoring Program Annual Reports.
Additional Scientific Study

Permit renewal also requires a closer look at the environment around Asplund and its outfall in Cook Inlet. In preparation for this renewal, AWWU conducted three years of additional sampling of water, sediment, and fish in Cook Inlet.

This information was used to develop a model showing how treated wastewater, or effluent, mixes and dilutes in Cook Inlet. A risk assessment also used the data to evaluate potential effects of the effluent on Cook Inlet beluga whales and the species they rely on for food.
Biological Evaluation

The results of the sampling, outfall monitoring, modeling, and risk assessment were brought together in a Biological Evaluation (BE). The Biological Evaluation examines the potential effects of treated wastewater from Asplund on threatened and endangered species and provides scientific information used as part of the permit renewal process. Explore the Biological Evaluation here.

Workers conducting sediment sampling on the beach of Cook Inlet.

Key Findings

AWWU’s permit application and Biological Evaluation conclude that Asplund’s cleaned and treated wastewater meets applicable approval criteria, water quality requirements and that the discharge is not likely to adversely affect Cook Inlet beluga whales or Steller sea lions. The EPA and the National Marine Fisheries Service will independently review the information as part of the permitting and consultation processes.

Data Supported Permit Application Process

Graphic showing key components of an NPDES permit renewal application. Inputs include water quality data collected since 1985, three years of water, sediment, and fish sampling plus outfall monitoring, a risk assessment, and a biological evaluation. These inputs support the NPDES permit application, which must meet water quality standards, demonstrate compliance with nine NPDES criteria, and show that Asplund’s discharge is not likely to adversely affect the Cook Inlet beluga whale or Steller sea lion.