Unintentional discharge of fully treated wastewater with possible elevated chlorine enters ocean at Pāpa‘ikou
The Hawaiʻi County Department of Environmental Management reports that an unintentional discharge of fully treated, fully disinfected wastewater from the Pāpa‘ikou Wastewater Treatment Plant has entered the Pacific Ocean offshore of Pāpa‘ikou.
The wastewater could possibly have elevated residual chlorine, the county said in a press release.
The failure, a bypass of the de-chlorination system, began at an unknown time after staff left the facility at about 3 p.m. on Tuesday. It was detected the next day at 8 a.m. when staff returned.
Staff added de-chlorination tablets to reduce chlorine levels while they repaired the system. Residual chlorine levels returned to normal at about 8:05 a.m., the county said.
Staff continued adding de-chlorination tablets until the dispenser system was repaired and returned to operation at about 12:56 p.m. on Wednesday. The cause of the dispenser system failure remains under investigation.
In February, the Department of Environmental Management reported a malfunction of the disinfection system that resulted in the discharge of fully treated, insufficiently disinfected, wastewater at the Pāpa’ikou Wastewater Treatment Plant via the facility’s existing outfall, which is located at the shoreline.
About 117,000 gallons of treated wastewater was discharged between 9 a.m. Oct. 20 and 8 a.m. Oct. 21. The precise amount discharged while the de-chlorination system was not functioning cannot be determined.
Upon detection, proper notification was made to the Hawai’i Department of Health. The County of Hawaiʻi is evaluating additional monitoring equipment and backup de-chlorination methods to to reduce the likelihood of future failures and reduce their potential impact.
