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Guam wastewater plants required to upgrade to secondary treatment

Release Date: 10/01/2009
Contact Information: Dean Higuchi, 808-541-2711,

(10/01/09) HONOLULU – The U.S. Environmental Protection Agency issued final decisions to deny the Guam Waterworks Authority’s permit variances exempting the Agana and Northern District wastewater treatment plants from secondary treatment requirements.

The EPA has concluded discharges from the two plants do not meet the Clean Water Act’s requirements as both plants discharge treated wastewater exceeding Territorial water quality standards for bacteria, designed to protect recreational activities such as swimming and fishing. Additionally, neither plant has met the minimum standards for primary treatment, which require 30 percent removal of total suspended solids and biochemical oxygen demand.

“We have determined that both wastewater plants fail to achieve the Clean Water Act requirements for a variance from secondary treatment,” said Laura Yoshii, the EPA's Acting Administrator for the Pacific Southwest region. “EPA will continue our work with the Guam government to protect the vital water resources of the island.”

GWA’s Agana and Northern District plants have been operating under variances from secondary treatment. With the final decision to deny the renewal of the variances, both plants will be required to upgrade to full secondary treatment. EPA will work with GWA to develop a schedule for implementing projects consistent with GWA’s priorities. GWA has invested in improvements to its wastewater collection system, significantly reducing sewage spills.

In reaching these final decisions, EPA considered public comments received in writing and presented verbally at a public hearing in Guam. Written responses to all comments received and EPA’s Final Decision Documents have been posted on EPA’s website.

The federal Clean Water Act generally requires municipal wastewater treatment plants to use both primary and secondary treatment. Amendments to the act in 1977 allow for variances from secondary treatment for marine discharges, provided the plant meets primary treatment requirements, water quality standards and other specific criteria as part of section 301(h) of the act. These variances are sometimes referred to as 301(h) waivers.

When secondary treatment is used, primary-treated wastewater receives additional treatment where a large portion of the organic matter in the wastewater is removed by making use of the bacteria in the sewage. There are a variety of different biological treatment techniques that allow the bacteria to consume most of the waste’s organic matter.

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