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KIHEI EFFLUENT REUSE SYSTEM
County of
Maui
(page 1 of 3)
INTRODUCTION
Kihei is located on
the arid south side of Maui. Potable
water for the region must be piped over ten miles from water wells
drilled into the Iao Aquifer located near Wailuku. The community uses approximately 65 percent of this water for
irrigation with the remainder ultimately ending up in the sanitary
sewer system. This wastewater is then conveyed to the County of Maui’s Kihei Wastewater
Reclamation Facility (WWRF) for treatment and disposal.
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The
Kihei WWRF is an activated sludge treatment facility that currently has
a peak dry weather capacity of 8 million gallons per day (mgd). The facility has undergone major upgrades in its treatment
capabilities with the addition of flocculation and chemical feed units,
effluent filtration, ultraviolet disinfection, and renovations to the
operations building. The plant is capable of producing R-1 effluent, which is the highest
quality of effluent designated by Hawaii State Department of Health (DOH)
Standards. Because R-1
effluent must undergo a high level of treatment, it has minimal
restrictions for reuse. |
Aerial view of
the Kihei WWRF |
In the past, the County of Maui has had difficulty in finding users for
the reclaimed water, primarily because of the high cost of conveying
the effluent to individual users. With the assistance of Fukunaga & Associates, Inc. (FAINC)
and the cooperative efforts of surrounding landowners, potential users
and the County, a functional system was constructed that meets the
needs of the users, best utilizes existing facilities at the Kihei WWRF,
and provides sufficient storage and transmission capabilities.
PROJECT DESCRIPTION
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The
County has constructed the major elements of the effluent reuse
system that includes the primary storage facilities, as well as a
major portion of the transmission and distribution system. These improvements have been installed in two projects: the
Kihei Effluent Reuse Core System and the Kihei Effluent
Reuse Distribution System, Phase I. The initial project, the Effluent Reuse Core System,
qualified as an innovative project and was eligible for a 100
percent low interest loan from the State Revolving Fund (SRF),
administered by the DOH. |
Extent of the Kihei Effluent
Reuse System |
The bids received on the project were very favorable, and
with minimal change orders required during construction, a surplus
of funds was available at the Core Project’s completion. A second project, the Kihei Effluent Reuse Distribution
System, Phase I, was added and provided a major distribution arm
for the system, serving the area north of the Kihei WWRF.
Kihei Effluent Reuse Core System
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The modifications had to be phased and scheduled to minimize impacts on
WWRF functions, since the facility had to maintain operations
throughout the project construction period. Major elements at the Kihei WWRF that were incorporated into
the reuse system included the effluent pumping station, equipped
with two 1500 gpm pumps, and the 1.8 million gallon effluent storage
basin.
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1.8 million gallon effluent basin |
The existing effluent storage basin was rehabilitated and
retrofitted with a polypropylene liner and floating membrane cover
system to maintain the high quality of the treated effluent produced
at the facility. The membrane liner and cover protect the effluent from debris and
contaminants, and reduce the potential for algae growth.
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