The U.S. Environmental Protection Agency could force the City and County of Honolulu to build additional capacity for its secondary wastewater treatment by refusing to renew a Clean Water Act waiver that allows water screening, grit removal and settling to be discharged at sea. EPA's tentative decision, issued March 28, could become final on May 29 when the comment period ends.

Parsons Corp.
Sand Island Wastewater Treatment Plant received
$170-million upgrade to correct problems similar to Honouliuli's.

EPA's refusal is based on the conclusion that the 27-million-gallon-per-day (MGD) Honouliuli Wastewater Treatment Plant does not meet water quality standards to allow for recreational activities, protection of fish and wildlife and protection of human life, says John Kemmer, associate director of the Water Division in EPA Region 9, San Francisco. Studies showed excessive discharges of both total suspended solids (TSS) and biochemical oxygen demands (BODs) from the plant through the Barbers Point deep ocean outfall 8,760 ft from shore, according to the EPA report. Under the Clean Water Act 30-day averages of TSS and BOD may not exceed 30 milligrams per liter.

EPA determined that the plant's effluent contains excessive amounts of dieldrin and chlordane, and two carcinogenic pesticides, at levels dangerous to recreational users. EPA findings further showed that the level of discharge could interfere with the protection of a balanced indigenous population of sea life since these chemicals proved toxic to sea urchins exposed to the effluent.

"We're reviewing how the EPA came up with this decision," says Ken Kawahara, spokesman for the City of Honolulu. "We don¹t agree with their position."

EPA's denial was unrelated to a sewage spill in March 2006 that forced closure of Waikiki beach. That accident stemmed from a break in the collection system, not the treatment system. A $20-million project is now under way to repair the aging infrastructure in the Waikiki and Ala Wai area.

For the treatment plant's effluent problem, the City and County of Honolulu proposed an educational, non-industrial source control program that is "insufficient," says Dean Higuchi, EPA spokesman. "The applicant has not demonstrated that its users are in compliance with pretreatment requirements and that it will enforce them," he says.

The City and County already operates a 12 MGD tertiary treatment facility for irrigation and industrial water. When available, unused treated water is mixed with the screened effluent to dilute it before marine discharge. That mitigation is intermittent and not sufficient to meet Clean Water Act standards.

If the proposed denial holds after the May 29 comment period closes, EPA will work with the City and County to find a solution. "We will not close the treatment plant," Higuchi says.

The exact treatment options have not been identified but the solution could be expensive. In 2006, Parsons Corp., Pasadena, Calif., completed a $170-million disinfection and head works project at Honolulu's Sand Island Wastewater Treatment Plant to the north, another facility that had operated under a similar variance until public pressure forced the operator to act. Construction included four channels of ultraviolet disinfection, an effluent pump station, two clarifiers, six screening channels, four aerated grit chambers, bio-filter trickling filters and catalytic carbon scrubbers for hydrogen sulfide gas reduction.