AWWA/HWEA 7th Annual Joint Conference! We are soft-launching the Pacific Water Conference Mobile App for the VERY FIRST time this year! Please feel free to let us know of any issues you encounter to help us troubleshoot and improve for next year’s full launch of the mobile app. Email pwc.publications@gmail.com for assistance with any mobile app issues.
In October, 2018, the County of Maui Department of Water Supply (DWS) started operation of the new Iao Surface Water Treatment Plant (WTP), which replaced the old Iao WTP located within the site of the 3.0 Million Gallon (MG) Iao Tank. The old Iao WTP was designed and constructed in-house by DWS in 1997 to treat water from the Iao-Waikapu Ditch to produce 1.2 million gallons per day (mgd) of drinking water. The WTP was constructed as a temporary facility to produce water for a period of roughly three years until more permanent source options could be brought on-line. The Iao WTP was upgraded in 2005 and produced approximately 1.7 mgd. By 2013, the old Iao WTP had long outlived its useful life, and DWS decided to proceed with the design of a permanent WTP to be constructed near the old WTP. The new WTP will be operated at approximately 3.2 mgd, with a maximum capacity of 6.0 mgd. The treated water is integrated into DWS’s Central Maui Water System. The new WTP consists of four low pressure membrane filtration units within the Filtration Area of a pre-engineered metal Treatment Plant Building (TPB). Also within the Filtration Area are duplex strainers, tanks and chemical equipment for the membrane cleaning process, and an on-site chlorine generation system. The TPB also has separate sound attenuated rooms for the generator, blowers and air compressors, air conditioned electrical equipment room, office/laboratory, break area and, storage rooms, and a restroom. Other major components within the WTP site are a Chlorine Contact Tank and dual Sludge Lagoons for gravity separation of solids in the backwash water from the membrane units. The liquid portion within the Sludge Lagoons is decanted for discharge into the Waihee Ditch, which required an NPDES Permit. The new WTP completely runs by gravity from the raw water intake through a self-cleaning screening unit at the Iao-Waikapu Ditch, through the membrane treatment system, to the chlorine contact tank and then to the Iao 3.0 MG Tank, without the need for pumps. The new WTP is also fully automatic with an extensive SCADA system. The SCADA system is a custom built application for the Iao WTP that monitors and controls the operation of the WTP. The SCADA System is a server based system which allows the operators to access the SCADA system remotely.
