Power Failure Results in Discharge of Partially Treated Sewage

An electrical failure at Hilo’s wastewater plant resulted in the discharge Thursday of nearly 72,000 gallons of partially treated sewage through the outfall at Puhi Bay.

According to a statement issued today by the county’s Wastewater Division, the bypass of part of the plant’s secondary treatment process occurred for 43 minutes Thursday night. It ended at 8:25 p.m. when a backup power source was employed.

One of the signs posted at Puhi Bay. Photo by Dave Smith.

Signs were posted along the bay’s shore to inform the public that the area was closed to swimming, fishing and boating.

Although the sewage was only partially treated, it had been disinfected with chlorine, the statement said.

The outfall is a 48-inch-diameter pipe which extends approximately three-quarters of a mile offshore from the former sewage treatment plant at Puhi Bay.

Under normal operations, fully treated and disinfected effluent from the current treatment plant located southeast of the Hilo airport flows to the outfall where it is discharged.

The statement said the wastewater division will monitor the shoreline waters daily to determine when to lift the warning.

***Updated at 5:31 p.m. to correct length of outfall.***