The Wastewater Division of the County of Hawai‘i Department of Environmental Management reports a discharge of partially treated wastewater from the Kula‘imano Wastewater Treatment Plant in Pepe‘ekeo on the evening of Friday, December 3, 2021.

The bypass of the aeration and disinfection processes resulted in the discharge of an estimated 14,340 gallons of partially treated wastewater via the facility’s existing outfall, which is located at the shoreline.

The cause of the process bypass was determined to have begun upon loss of Hawai‘i Electric Light Co. power, whereupon the emergency standby generator was automatically activated. However, the generator was not delivering power to the aeration system blowers or to the disinfection system, resulting in the bypass of those processes. Before restoration of HELCO power, wastewater division personnel initiated manual disinfection and diverted the incoming flow to the spare aeration tank in an effort to slow the rate of effluent discharge.

Electricity was restored at approximately 8:40 p.m., and the plant resumed normal operations at 8:43 p.m.