Firm gets national accolades for big sewer project you’ve probably never heard of
HONOLULU (HawaiiNewsNow) - Connecting the Ala Moana Wastewater Pump Station and Sand Island Wastewater Treatment Plant are the city’s two new 7,500-foot long and 63-inch diameter wastewater force mains.
They were installed deep beneath the surface.
“We needed to make sure we had capacity to handle all the excess flow coming in, and also redundancy,” city Environmental Services Department director Lori Kahikina said.
Civil engineering firm Fukunaga & Associates Inc. designed the massive project, which took years to complete and was full of challenges.
Work required boring shafts 100-feet deep then using a giant drill to micro-tunnel through soil and lava rock to place the pipes under Honolulu Harbor.
"After you get down in the shaft you had to go across the channel, which then encountered some hard and soft material," company president Jon Nishimura said.
The pipes had to be set deep enough beneath the harbor bottom so construction wouldn't disturb shipping lines and other harbor traffic.
"Shipping traffic could not stop, obviously," Nishimura said.
Plus the work couldn’t disrupt wastewater service. The new force mains replaced old ones that serve more than 200,000 households and businesses in metro Honolulu from Nuuanu Stream to Kuliouou..
The American Council of Engineering Companies recently honored Fukunanga & Associates with a National Recognition Award for engineering achievement ― a big award in the engineering field.
"We're happy to get recognized and happy that we could do a good job for the city," Nishimura said.
The Honolulu Wastewater System Improvement Project went as planned, finishing on time and according to the city $45 million under budget.
The work was done with no fanfare.
"I think that's a good point that we were under the radar. Nobody even knew what we were doing. That's how we like to do our projects," Kahikina said.
The force mains carry an average of 45 million gallons of wastewater a day, and more when it’s raining. The new pipes give the city options.
“They can now utilize their two pump stations located at the site, and they’re able to divert flows in at least three different directions,” Nishimura said.
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