Honolulu Faces $1.2 Billion Wastewater Treatment Upgrade

The Sand Island plant's discharged water currently does not meet water quality standards set to protect marine life or human consumption of fish, the EPA says.

The Sand Island plant discharges treated wastewater into Mamala Bay via the Sand Island outfall located at a depth of 230 feet below the ocean's surface. Treated wastewater is discharged from a multi-port diffuser located 9,000 feet, nearly two miles, offshore.

Honolulu conducts tests of Sand Island wastewater using two aquatic species, one of which is a Hawaiian sea urchin. Honolulu submitted data on this type of testing as part of their application for a variance. The results showed that the wastewater often produces toxic effects in test sea urchins and fails to meet the Hawaii Department of Health standard for ammonia.

EPA's review of test data also showed that wastewater samples exceeded Hawaii Department of Health criteria for two pesticides, dieldrin and chlordane, established to protect against carcinogenic effects.

Honolulu has improved the bacteria count in wastewater around the outfall. Bacteria data collected through the end of 2006 shows that bacteria levels exceed the national criteria established to protect recreational activities. But beginning in 2007, after Honolulu began operation of an ultraviolet light disinfection system, bacteria levels in the vicinity of the Sand Island outfall were found to meet national criteria for protection of recreational activities.

"Today we have made a tentative determination that the Sand Island plant does not meet the Clean Water Act requirements, and will need to be upgraded to provide improved wastewater treatment prior to discharging into Hawaii's ocean waters," said Wayne Nastri, the EPA's Administrator for the Pacific Southwest region.

"Through this action and findings we made earlier this year regarding the Honouliuli plant, we intend to work with the city to upgrade its two largest wastewater plants. These upgrades will ensure that Hawaii's residents, visitors and marine life benefit from the full protections provided by the Clean Water Act."

The city's Sand Island plant, located in Honolulu, is currently operating under a variance from secondary treatment. If the EPA's proposal becomes final, the plant will be required to upgrade to full secondary treatment.

Primary treatment 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 most of the organic matter in the wastewater is removed by making use of the bacteria in the sewage.

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

Mayor Hannemann said in August, "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."

"These expenses are unnecessary at this time," said the mayor. "Our first priority must be to work with EPA officials to address far more pressing needs to improve our collection system - the 1,400 miles of underground mains that carry wastewater to our treatment plants. It is the condition of our collection system that poses a risk to public health and that is where we must focus our efforts."

The city and county of Honolulu has plans for nearly $1.5 billion in upgrades of Oahu's wastewater collection and treatment systems over the next six years, Hannemann said.

The EPA informed Honolulu of a tentative denial of the waiver for Honouliuli in March, and was expected to take similar action for Sand Island this fall, the mayor said. "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.

The Sand Island wastewater treatment plant serves a population of approximately 412,000 including both residents and tourists. Approximately 66 million gallons per day of raw wastewater is treated at this facility.

The EPA's tentative decision will be available for public comment through February 29, 2008. A public hearing on the tentative decision will be held on February 5, 2008 at 6:30 pm at the Washington Intermediate School in Honolulu.

At the completion of the public comment period, the EPA will consider all public comments and make a final decision on the variance application.

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