Water panel seeks solution for S. Maui irrigation
Scalping facilities proposed to reduce recycled wastewater costs for landscaping
Melissa Tanji
mtanji@mauinews.com
A sprinkler waters a plot of grass and palm trees near the intersection of Makena and Makena Keonoio roads Wednesday afternoon in South Maui. Members of the Maui County Council's Water Resources Committee heard a presentation Wednesday on ways to reduce the use of drinking water for landscape irrigation. The Maui News / MATTHEW THAYER photo
Knowing that 1 million to 2 million gallons of drinking water every day irrigates Wailea and Makena landscapes, Maui County administrators and County Council members have begun exploring ways to find alternatives.
On Wednesday, the Maui County Council Water Resources Committee heard a presentation from Department of Environmental Management Director Stewart Stant, who is working with Department of Water Supply Director David Taylor and committee Chairman Alika Atay to reduce the use of drinking water for landscape irrigation. No committee action was taken.
Stant suggested using water-scalping facilities, which convert and treat raw sewage to transform it to reuseable water.
The facilities would be located near wastewater pump stations in the vicinity of large resort and condominium properties, alleviating the need for a lot of infrastructure to disperse the treated water.
For example, one pump station, station No. 16, is a few blocks away from the Grand Wailea, Stant said. Other stations are near condominiums.
In general, wastewater is pumped to a wastewater treatment facility, which could be miles away. Then, after treatment, it's ready to be pumped back to wherever the water is needed.
Stant said the close proximity of the scalping facilities to the irrigation projects would alleviate the cost of infrastructure. And by having these facilities, there would be savings in the cost of building or upgrading centralized sewage treatment plants.
Atay said the scarcity of drinking water on an island makes it important to find a way to avoid using 400 million gallons of drinking water a year for landscape irrigation.
Taylor said the aim is to find ways to make more potable water available for homes, businesses and agricultural uses.
This helps the Department of Water Supply stretch its supply of drinking water.
Lisa Paulson, executive director of the Maui Hotel and Lodging Association, was not at the meeting, but she said in a phone interview Wednesday that she was glad that the dialogue has started to find ways for hotels and resorts in Wailea and Makena to be able to use high-quality recycled water.
Already, some West Maui resorts and hotels are using recycled water to irrigate landscaping, she said. South Maui properties would like to do the same.
So far, at least a couple of council members outright thought it was a good idea to pursue the scalping facilities, but they wanted more details, including cost estimates.
Because there are no scalping facilities in Hawaii, Stant said it would be hard to determine costs accurately.
But he said the state is working on a pilot project to test different types of wastewater disinfecting systems, which include the Wailuku-Kahului Wastewater Reclamation Facility and Kahului Airport.
Stant said he would be in a better position to estimate costs and assess project details in the next several months.
Outside the meeting, Stant said the scalping facilities would not come close to the estimated $5 million to $10 million it could cost to install a pipe for treated wastewater to reach the Wailea and Makena areas.
Now, the Kihei Wastewater Reclamation Facility, mauka of Piilani Highway along East Welakahao Road, produces R-1 quality water and distributes it through the South Maui recycled water system.
The system includes Maui Nui Golf Club, the Kihei Fire Station and Piilani Gardens apartments, the county has reported.
Stant explained that the scalping facility's equipment could fit in a 40-foot container. It would include a membrane bioreactor, which is a secondary wastewater filtration process that combines biological treatment and mechanical filtration. Effluent from the process still contains some impurities and is classified as R-2 quality water. (A lower quality of recycled water from R-1).
But with further ultraviolet disinfection treatment or other treatments, the effluent from the membrane bioreactor process would reach R-1 quality, according to materials provided with Stant's presentation.
* Melissa Tanji can be reached at mtanji@mauinews.com.
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