HONOLULU — Mayor Rick Blangiardi on Friday commemorated the full secondary treatment upgrade of the Honouliuli Wastewater Treatment Plant, the second phase as noted in the consent decree negotiated in 2010.

What You Need To Know

  • The upgraded facility has been turned over to the operations staff of the Department of Environmental Services ahead of the June 1, 2024, deadline, and marks a significant step toward meeting federal Clean Water Act regulatory requirements by the City and County of Honolulu

  • The negotiated 2010 consent decree encompassed three phases working within a 25-year implementation schedule, the longest timeframe allowed by the EPA

  • Phase 1 was the upgrade of the sewer collection system; Phase 2 was the secondary upgrade of Honouliuli WWTP; and Phase 3 is the secondary upgrade of Sand Island WWTP

  • ENV said the secondary upgrade of Sand Island WWTP will be done in two phases

Totaling $536 million, the comprehensive upgrade included the installation of aeration basins, a blower building equipped with turbo blowers, a mixed liquor distribution box, secondary clarifiers, and a secondary process pump station, according to a news release.

Improvements were also made to various aspects of the primary treatment process, in addition to upgrades to civil infrastructure, electrical systems and SCADA technology.

Originally commissioned in 1978 as a primary treatment facility, Honouliuli WWTP was upgraded to partial secondary treatment in 1996, and has now been elevated to full secondary treatment capacity incorporating modern and efficient technology.

The upgraded facility has been turned over to the operations staff of the Department of Environmental Services ahead of the June 1, 2024, deadline, and marks a significant step toward meeting federal Clean Water Act regulatory requirements for the City and County of Honolulu.

The consent decree filed in federal court on Dec. 17, 2010, put a stop to years of legal action including a Sierra Club lawsuit and the 2007 Beachwalk lawsuit, and resolved litigation over secondary treatment waivers, along with U.S. Environmental Protection Agency and Hawaii Department of Health compliance orders, according to the release.

The negotiated 2010 consent decree encompassed three phases working within a 25-year implementation schedule, the longest timeframe allowed by the EPA.

Phase 1 was the upgrade of the sewer collection system; Phase 2 was the secondary upgrade of Honouliuli WWTP; and Phase 3 is the secondary upgrade of Sand Island WWTP.

From 2010 through fiscal year 2020, the city spent roughly $1.3 billion in capital costs on the Phase 1 upgrades to the collection system consisting of nearly 2,100 miles of pipes, 72 wastewater pump stations and associated force mains. Roughly 100 million gallons of wastewater is treated daily.

ENV said the secondary upgrade of Sand Island WWTP will be done in two phases. Set for completion in 2026, the first phase is currently 50% done. The second phase will start in 2029 with completion set at the consent decree deadline of Dec. 31, 2035. The Sand Island facility is an enhanced primary plant that incorporates ultraviolet disinfection of effluent before being discharged in the deep ocean.

The city acknowledges that the burden of funding consent decree-mandated projects falls on Honolulu ratepayers and utilizes funding opportunities to save money and resources. They continue to work with regulators to employ modern and efficient technology to ensure a clean environment for the future.

Sarah Yamanaka covers news and events for Spectrum News Hawaii. She can be reached at sarah.yamanaka@charter.com.