Xylem Inc. has released a white paper outlining strategies to increase the resilience of cities around the world.
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Located on the island of Maui in Pukalani, Hawaii, the Pukalani Wastewater Reclamation Facility underwent an upgrade in 2009, but the multimillion dollar construction project was not without its challenges.
The Hawaii Water Service Co. had a number of goals. The first was to replace an existing 33-year-old steel tank carousel facility with a new membrane facility, for golf course irrigation, while maximizing the limited available space. The company also hoped to rehabilitate two facility lift station structures and install new variable frequency drive pumps in the main lift station.
To achieve these goals, construction had to take place in a constrained area between the old facility and the operations building. Furthermore, there were no drawings of the original facility available, so builders had no way of knowing the location of electrical duct banks and aeration piping in the space.
Contractors from Bodell Construction Co. performed several geotechnical borings and discovered an underground electrical duct bank and hard blue lava in the building space. The electrical work had to be rerouted and the lava had to be removed without disturbing area residents with noise and vibrations.
In the end, the project was a success. During Phase 1, completed in June 2011, all process basins, screening, pumps and blowers were constructed to accommodate an initial flow of 160 gal per minute (gpm). Equalization and sludge holding basins also were built to accommodate a final flow of 320 gpm, which can be achieved with the installation of six additional membrane cassettes. The height of the basin walls was increased by 4 ft, and two future permeate headers were added to accommodate a second phase.
“We are extremely proud that we were able to utilize technology and a design that has a smaller footprint, is less costly to maintain and produces water that can be used without restriction, which frees up precious potable water supplies,” said Jim Smith, general manager of the Hawaii Water Service Co. “That’s a win-win for Hawaii Water, our customers and the environment.”