Challenge

As environmental standards changed, the City of Honouliuli found itself under a federal consent decree to improve its wastewater treatment and disposal. At the same time, the city’s potable and drinkable water resources were strained by population and tourist growth. As a result, the city faced the costly challenge of finding a new solution for water treatment that would be as cost effective as possible for taxpayers and comply with a changing environmental regulatory environment. 

Solution

The answer to address the challenge was a public-private partnership with Siemens Water Technologies (formerly USFilter) to save the city and taxpayers millions of dollars in construction, maintenance and operating costs by spreading out costs over a 20-year period.  The facility uses the Hydro-Clear® filter system for wastewater polishing, followed by ultraviolet disinfection to produce irrigation water. A Memcor® CMF membrane system followed by reverse osmosis turns secondary effluent into “ultrapure” water. 

Results

The 12 MGD facility in Oahu, at the time the largest reclamation project of its kind in the Hawaiian Islands, produces beneficial reuse water from effluent previously discharged into the Pacific Ocean.  

The process generates two grades of water:

• High-purity water for power and petro-refining companies
• Irrigation water

As a result, the amount of available water for residential needs has increased by approximately 2 MGD/day—an important aspect for an island surrounded by salt water.