Trial Run: City Will Haul Excess Sewage Sludge to Ewa Plant

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Sand Island Wastewater Treatment Plant

BY MIRIAM LANDRU – The City & County of Honolulu, including the Department of Environmental Services, held an informational briefing Monday night at Mission Memorial Auditorium to address the wastewater sludge capacity issues at Sand Island Waste Water Treatment Plant.

The Sand Island plant has been processing solid waste in the Honolulu area since 1976. The plant treats 60-70 million gallons of wastewater a day and is the largest wastewater basin out of 8 on Oahu.


In 2004, the city abandoned the use of low-pressure oxidation system, which was used to treat sludge before sending it to the landfill. Instead, city officials incorporated pellet reuse made possible by the digester at Sand Island designed by Synagro, a corporation which creates “sustainable solutions to eliminating waste.”

The digester produces Class A pellets, which are used for Department of Health approved fertilizer and biogas which is green energy. DOH standards are much more stringent than those of the EPA.

“It’s a very highly tested material. The EPA came out with standards 30 years ago. We test everything we make and we send it to the Hawaii Department of Health and they give us permission,” said Bill Massa, Synagro CEO.

Currently, there is only one digester at the Sand Island plant. The city of Honolulu recognizes the need for a second digester, but there is not enough money in the budget. Honolulu City Council Members, headed by Council Member Romy Cachola, were opposed to the plan to expand Sand Island and removed funding.

To decrease the sludge, the city will truck loads of sewage to the Honouliuli plant in Ewa for the next 30 days. The operation will start this month and will be limited to one truck-load per day.

Wastewater treatment plants in Waianae and Kailua were originally considered for excess capacity. However, Waianae is still recovering from the trucking of the floodwater from the Waimanalo Gulch Landfill breach that happened last Winter.

The Kailua treatment plant is currently undergoing refurbishing on the fourth and last digester. This is expected to be complete within the next 6–10 months, after which time the plant will begin accepting excess sewage as part of a feasibility study and environmental assessment. This plant, which is adjacent to an elementary school, a park and a housing complex, also experienced pipe breakage and sewage discharge this week.  The sewage has been cleaned up and disinfected, however foul odors are still lingering in the air.

“For many years there have been complaints about the odor. We have initialized a new project to capture the air. We have gone in and put air conditioning in the school. I believe that’s a help,” confirmed ENV Director Tom Steinberger.

Still, the temporary method of trucking the sludge has critics.

“It’s a waste of money. They should put that money into the 2nd digester,” said Rep. Cynthia Thielen, who represents Kailua in the State House.

“There’s a lot of different ways to solve problems, but a second digester is the best solution for Honolulu. It was always imagined there would be a second digester there because of the population growth of the city,” Massa agreed.

A City Council Briefing on this issue will be held this Wednesday, August 3 at Honolulu Hale. Written and oral testimony will be accepted.

Corrections have been made to this story as per the request of the City & County.