For decades, Honolulu has used science to back up its argument that the treated sewage piped into the deep ocean off Sand Island and the Waianae coast hasn’t had a significant negative impact on the marine environment.

However, the city, already under federal mandate to upgrade its aging sewer system, now may also have to invest additional billions in extra wastewater treatment to meet U.S. Environmental Protection Agency standards. Currently, sewage is disinfected once.1 The EPA is pushing for a second treatment that would remove more biological matter from the wastewater before it is discharged.

Amidst an ongoing debate over whether the cost of additional treatment is justified by the environmental benefits, the City Council is considering a resolution that allows the University of Hawaii to the monitor biological impacts of the sewage discharged from the Sand Island and Honouliuli wastewater treatment plants. The resolution comes at the request of the city administration, which is required to monitor the water to keep its permits.

It will be interesting to see what the results of the monitoring will show, given the city’s position on its current treatment practice. Join the discussion on Honolulu-related issues here.

  1. Clarification: A reader pointed out that a previous version of this update might have given the impression that raw sewage was being pumped into the ocean. I’ve updated the article to make it clear that the wastewater is disinfected once and the issue is whether it should be put through another treatment to remove more biological matter, which is the EPA standard.

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