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Wastewater Treatment Plant:  Paalaa Kai WWTP

Paalaa Kai Wastewater Treatment Plant (1980)
  • Secondary level of treatment
  • Processed 78,500 gallons per day (FY13)
  • Injection Wells
  • Estimated 20-year CIP funding: $464 million

The Paalaa Kai Wastewater Treatment Plant (WWTP), built in 1980, is an activated sludge secondary treatment plant, which services the Paalaa Kai community, located between Waialua and Haleiwa town on the North Shore of Oahu.


The Paalaa Kai WWTP is designed for an average daily treatment capacity of 144,000 gallons per day and a peak capacity of 648,000 gallons.   The current average daily flow is approximately 78,500 gallons.


The treated wastewater is disposed of via injection wells, which are located on site.  In addition, the solid wastes generated by the treatment process are hauled to the Honouliuli WWTP for processing and final disposal.


The Paalaa Kai WWTP operates under an Underground Injection Control (UIC) Permit No. UO-1258, issued Sept. 28, 2012, and expires Sept. 27, 2017.  The UIC permit and applicable Zone of Mixing (ZOM) authorizes the City and County of Honolulu to dispose secondary treated domestic wastewater effluent from the facility to the underground in accordance with the effluent limitations, monitoring requirements and other permit conditions.

Last Reviewed: Monday, September 23, 2013