Honolulu Must Spend Over $1 Billion on Wastewater Treatment

The decision forces the city to upgrade both plants to bring them into compliance with federal laws. City officials have said these upgrades could cost more than $1.2 billion.

The federal agency has concluded that the discharges from the two plants do not meet the Clean Water Act's conditions for renewed variances from requirements which apply to most of the nation's municipal sewage treatment plants.

The discharges from the two plants do not meet all applicable water quality standards. Neither of the plants' discharges protect recreational use or marine life in the vicinity of the ocean outfalls. As a result, the two plants do not qualify for renewed variances.

"This action will ensure that residents and visitors using Hawaii's ocean waters are protected from inadequately treated sewage," said Wayne Nastri, the EPA's administrator for the Pacific Southwest region.

"We will work with the city on a realistic schedule to upgrade its two largest wastewater plants, taking into account the other priorities for improvements to Honolulu's wastewater system," Nastri said.

The city's Sand Island plant, located in Honolulu, and the Honouliuli plant, located in Ewa, were both operating under variances from secondary treatment. With the final decision to not renew the variances, both plants will be required to upgrade to full secondary treatment.

Honolulu's Sand Island wastewater treatment plant (Photo courtesy Parsons)

The Sand Island plant handles wastewater from the city of Honolulu and the resort area of Waikiki. The Honouliuli plant receives wastewater from the rest of the island of Oahu. The island's total population now stands at more than 905,000 residents, and Oahu hosts more than 485,500 visitors a month, according to data compiled by the state of Hawaii.

Honolulu Mayor Mufi Hannemann and the City Council have been aware of the possibility that the EPA might not renew the permit variances since 2005 and have held several public meetings to address the upgrades that might be needed at the two plants.

Mayor Hannemann said in August 2007, "To upgrade these two plants to full secondary treatment, the city will need to expend an estimated $1.2 billion for construction at the facilities. This expense doesn't include the increased cost to operate and maintain the expanded plants nor does it include the additional energy consumption and greenhouse gas emissions of secondary treatment."

"Providing full secondary treatment at Sand Island and Honouliuli wastewater treatment plants will drive monthly residential sewer fees as high as $300 in less than 20 years," he warned.

In reaching these final decisions, EPA considered nearly 600 comments received in writing and presented verbally at two public hearings.

Written responses to all comments received have been posted on EPA's website. In response to these comments, EPA made modifications to tentative Decision Documents released in 2007, but these changes did not alter the overall conclusions that the two plants do not qualify for renewed variances.

Primary treatment generally involves screening out large floating objects, such as rags and sticks, removing grit, such as cinders, sand and small stones, and allowing wastewater to settle, followed by the removal of collected solids.

When secondary treatment is used, primary-treated wastewater flows into another facility 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.

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 water quality standards and other specific criteria as part of section 301(h) of the act.

Nastri said many coastal cities that once sought variances from secondary treatment, especially in areas where there is heavy recreational beach use, have chosen to upgrade their treatment plants to meet Clean Water Act requirements without variances.

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