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The U.S. Environmental Protection Agency has proposed to not renew the city and county of Honolulu’s permit variance that exempts the Honouliuli Wastewater Treatment plant from full secondary treatment requirements.
If the EPA’s proposal becomes final, the plant will then 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 necessary, the 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. The bacteria can consume most of the waste’s organic matter by using a variety of different biological treatment techniques.
According to the Hawaii Reporter, the Honouliuli plant’s discharged water results exceeded the national criteria for allowable levels of bacteria. These levels are put in place to protect recreational use of state waters, but does not meet water quality standards that have been designed to protect marine life or fish that will be consume by humans.
EPA’s tentative decision will be available for public comment through May 29, 2007. A public hearing on the proposal will be held on May 15, 2007. When the public comment period has ended, EPA will make a final decision on the variance application.
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 is able to meet water quality standards and other specific criteria as part of section 301(h) of the act.
According to the Hawaii Reporter, many coastal cities which 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.