KIHEI EFFLUENT REUSE SYSTEM
County of Maui
(page 3 of 3)

The Phase I Distribution System included the extension of the effluent transmission line from the Kihei WWRF in the makai direction, across Piilani Highway, then northward along the proposed North-South Collector Road corridor to the Kihei Community Center site. Approximately 6,200 linear feet of 12-inch, and 1,700 linear feet of 18-inch, ductile iron pipe was installed for this project. The system serves the Kihei Community Center, Kihei Elementary and Lokelani Intermediate Schools, Haggai Institute and the Piilani Commercial Center. The effluent line was also outfitted with fire hydrants to aid firefighters in control of brushfires that frequently occur in the area. Per DOH standards, the fire hydrants are painted purple to identify them as part of the reclaimed water system.

Fire hydrant painted purple to identify it as part of the reclaimed water system

The construction cost for the Kihei Effluent Distribution System, Phase I, was $682,000. Total construction time was 8 months, with substantial construction completed in December 1998. The contractor for the project was Goodfellow Brothers, Inc.

CONSULTANTS’ ROLE IN PROJECT

As the prime engineering consultant, Fukunaga & Associates, Inc. worked with the County of Maui on the project from its inception, handled the planning and design, and assisted during construction. A major concept that needed to be accepted by users of the system and the general public was that the treated effluent should be considered as a commodity having value and not simply as something that just needed to be disposed of. The high quality of the effluent needed to be preserved throughout the storage and transmission process to foster user confidence and minimize operational and maintenance problems. The availability of covered effluent storage, coupled with the installation of a pressurized distribution system allowed maximum flexibility for the County and the users of the system. The pressurized system allows users to simply tap into the system without the need for booster pumping.

 A major challenge was to best utilize existing facilities at the Kihei WWRF without compromising the function and operation of the final effluent reuse system. Pumping unit capabilities were tested and evaluated to insure that the existing units would function effectively in the finished system, as well as during the transition period while the system was in construction. The refurbishing of the existing effluent storage basin by installing a membrane lining and floating cover provided a significant improvement in preserving the system’s effluent quality. Coordination and phasing of the work was also crucial in maintaining service to existing system users and in avoiding interruption of treatment facility operations.

 The subconsultants, MK Engineers, Ltd. and Shigemura, Lau, Sakanashi and Higuchi, Inc. (SLSH), provided electrical and structural engineering services, respectively. MK Engineers, Inc. worked with the County staff and vendors of Supervisory Control And Data Acquisition (SCADA), radio and solar power systems, to develop a solar powered reservoir level control system linked by a radio telemetry system to the County’s SCADA system and effluent pumping station at the Kihei WWRF. The SCADA system is programmed to start and stop the effluent pumps and to control valves that permit irrigation of the Elleair Golf Course and the Monsanto Corporation’s seed corn operations. SLSH worked with the County to optimize the storage reservoir design, utilizing an aluminum geodesic dome cover, in lieu of a conventional concrete roof slab, resulting in cost savings for the County.

CONCLUSION

The Kihei Effluent Reuse System has met its goal of providing the County of Maui with a system that is beneficial to the community by preserving its potable water resources, and utilizing reclaimed water for irrigation of parks, landscape areas and a golf course, and for fire protection. The reclaimed water is also used by a major agricultural operation, Monsanto Corporation, for the production of high quality seed corn that is marketed worldwide. The system has proven to be easy to operate and reliable, and has met the needs and expectations of the County

The Kihei WWRF currently reclaims between 40 and 50 percent of the wastewater it treats, typically between 1.6 and 2.0 million gallons per day. The rest of the treated effluent is discharged through injection wells located on the WWRF site. It is envisioned that the Kihei WWRF will eventually reclaim 100 percent of its flow as public acceptance and demand for the high quality effluent increases in the future.