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As wastewater discharge permits become more stringent and equipment and processes at wastewater treatment plants become antiquated, small communities face significant challenges to meeting new permit levels and paying for these improvements. One such city facing this challenge is the City of Ukiah, California, located approximately 120 miles north of San Francisco in Northern California. The City of Ukiah owns, operates, and maintains a wastewater treatment plant serving a population of approximately 20,500 people within the City and Ukiah Valley Sanitation District. The wastewater treatment plant was expanded in 1983 and 1995, but most of the original facilities constructed in 1958 are still in use. High maintenance requirements of the older, outdated equipment, lack of adequate redundancy, and little operational flexibility make it difficult for the plant to reliably meet permit limits.

This led the City to take on the largest project in its history. The goal of the Wastewater Treatment Plant Improvement Project is two fold. The primary goal is to design and construct a wastewater treatment system that reliably meets effluent requirements for the design year 2025. A second goal of the project is to produce Class A Biosolids, which will significantly increase disposal options, especially in the agriculturally rich Yokayo Valley. The City identified three key planning items pivotal to the success of the Wastewater Treatment Plant Improvement Project:

address future National Pollutant Discharge Elimination System permitting requirements

evaluate the existing plant and determine the plant capacity

identify sources of funding for the project

After the completion of the plant evaluation and capacity analysis, it was apparent that the conceptual project construction cost estimate provided to the City in 2000 was not accurate. The new construction cost estimate of 43,500,000 was three times higher than the original estimate of 14,000,000. With this unexpected increase, the City of Ukiah had to become resourceful and innovative in searching for funding sources. This paper focuses on the approach the City used to meet the challenges of their Wastewater Treatment Plant Improvement Project.
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Document Type: Research Article

Publication date: 2004-01-01

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