Sewage project essential for O'ahu
By Johnny Brannon
Advertiser Staff Writer
The cost of major upgrade work to Honolulu's Sand Island Wastewater Treatment Plant and adjacent sewage facilities is steadily rising and partly behind schedule, but officials say the final product will ensure the environment is protected and that O'ahu is prepared for growth.
Richard Ambo • The Honolulu Advertiser
The project is one of the most costly and complex public works efforts the city has ever undertaken, and its price is now approaching $300 million as design work evolves and construction takes shape.
Work under way at the Sand Island wastewater treatment plant and adjacent sewage facilities includes major upgrades to three pump stations and an interim chemical treatment facility to disinfect sewage.
The improvements include eight major components that must interact precisely with existing facilities without diverting the 75 million gallons of wastewater the plant treats every day — about two-thirds of O'ahu's sewage.
The plant serves neighborhoods stretching from Moanalua to Niu Valley, and should be able to handle up to 250 million gallons a day after the upgrades are complete, city Environmental Services director Tim Steinberger said.
"That would be at peak flow times, which would include runoff from serious storms," he said.
The project is required to meet federal wastewater discharge guidelines and an agreement with the Environmental Protection Agency. It includes dozens of design, construction and management contracts with a slew of private firms.
Two components account for a big chunk of the project's cost, and change orders have increased the price of each: a "headworks" unit that will connect huge sewage pipes to the treatment plant and filter the inflow, and a disinfection unit to kill pathogens with ultraviolet light before the effluent is pumped into the deep ocean about two miles offshore.
Just under 10 percent of the headworks project has been completed so far, and the $80.6 million contract awarded in October to Robison Construction Inc. has increased by $1,569,000 with four change orders for added work, city records show.
And the original $3.6 million design contract for the unit, awarded to R.M. Towill Corp. in 1997, has been amended eight times and increased to $6.2 million. It is expected to reach $7.9 million by the time that part of the project is finished, officials say. The city is also paying at least $1,455,000 to M&E Pacific Corp. to manage the construction.
City managing director Ben Lee said the costs are not out of scope with a project of this magnitude and the changes do not mean the project is over budget. The design contract was expected to be continually renegotiated as work progressed and allowed engineers to make more detailed cost estimates, he said.
The disinfection unit is 41 percent complete so far, Department of Design and Construction engineer Guy Inouye said.
The $76,681,165 construction contract, also with Robison, was awarded in May 2001 and has had nine changes orders so far that decreased it to $70,187,578, records show.
But one of the changes was to move part of the work — the manufacture of four huge pumps — to a separate $6,745,284 contract with Sumitomo Corp. That brought the total cost back up, to $76,932,862. Lee said the contracts were separated because of tax and liability concerns by the manufacturer.
The disinfection unit's $2.7 million design contract, awarded to Brown and Caldwell in 2000, was later increased by $4.35 million. That's largely because officials decided during the design phase to incorporate a new pump station into the unit, Steinberger said.
The construction management contract, with R.M Towill, has increased from $500,000 to $1 million, and is expected to total $3 million by the time the unit is operational.
The project was originally to be completed by June, records show. But it fell behind schedule because contract negotiations took longer than expected and engineers ran into problems with coral embedded in the soil underneath the site, Lee said.
"When they started digging, they found the coral was more dense than porous," he said.
That made it harder to ensure that compounds injected into holes drilled in the coral for part of the unit's foundation have bonded correctly, and additional testing will now be required, according to Lee.
Other key elements of the Sand Island project include major upgrades to three pump stations; the construction of two additional clarifiers — huge cement tanks that separate sludge from liquid — to complement the existing six; a major new sewer line, called a "force main;" and an interim chemical treatment facility to disinfect sewage while the ultraviolet unit is under construction.
Eventually, dried sludge that is now hauled to the Waimanalo Gulch landfill — which is rapidly reaching its permitted capacity — will be turned into compost pellets at Sand Island and marketed by a private firm.
The existing Sand Island plant has been cited by the EPA and the state Health Department for failing to meet minimum sewage treatment requirements, and the upgrades are meant to address such concerns.
The plant is one of the few in the nation that has been granted a special waiver by the EPA to dump sewage after it has received only a primary level of treatment. Most other cities must perform more costly but thorough secondary treatment that purifies wastewater before it is dumped into inland waterways or shallow seas off coastal states.
Environmental groups sued Honolulu in 1990 to force it to upgrade the Sand Island plant to secondary treatment, and the case was later settled out of court on the condition that an environmental study be conducted.
The study concluded in 1995 that secondary treatment was not necessary because Honolulu's sewage is quickly diluted by the deep ocean waters off O'ahu, but that some additional treatment was necessary.
In a report released in February, the Health Department rated the plant "unsatisfactory" because effluent contained higher than allowable levels of the toxic chemicals dieldrin and chlordane, state records show.
Both substances were commonly used as pesticides in Hawai'i until the EPA banned them in the 1980s because of health concerns, but runoff from contaminated soil still enters the sewer system. A federal monitoring study released last year found that O'ahu's urban streams contain the nation's highest levels of dieldrin and chlordane.
The Health Department also cited the Sand Island plant for deteriorated equipment, questionably calibrated meters that measure the flow of effluent, and for short staffing levels, records show.
Reach Johnny Brannon at jbrannon@honoluluadvertiser.com or 525-8070.
