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Meeting Discharge Requirements and more in an old Trickling Filter Plant on a Shoestring Budget - An Interesting Case History

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The City of Fillmore's WWTP, serving a population of 14,000 people in Ventura County, California is a trickling filter (TF) plant that was constructed in the 1950's. The plant is currently treating 1.0 mgd of domestic wastewater and has been in violation of effluent requirements for a number of years. As a result of these violations, the City had imposed a building moratorium on any future developments until the violations were remedied. In 2008, the City will construct a new plant (2.5 mgd capacity) at an entirely new site, which will be state-of-the-art with tertiary treatment, partial nitrogen removal, and UV disinfection. Until then, the City is under RWQCB mandate to upgrade the existing plant to comply with the discharge standards, which have been relaxed, under a Time Schedule Order, to 45, 45 (45 mg/L of BOD and TSS on a 30 day average basis) instead of 30, 30 that were required earlier. Even with the relaxed standards, the existing plant had to be upgraded to consistently achieve 45, 45 effluent quality and be able to serve approximately 1,000 additional homes that were expected to come on line prior to the new plant being completed. The upgrading involved chemical addition to the primary clarifier; significant improvements to the TF including placement of additional media on top of the existing rock media, forced air ventilation, and installation of an electric driven rotary distributor; polymer addition to the secondary clarifier; and improved management of the sludge recycle streams. The City constructed these improvements using locally available materials and equipment in most cases, and for the first time in several years, the plant is now producing an effluent which is generally in the range of 15-20 (and sometimes less) in BOD and TSS. As a result of these improvements, the City is now beginning to allow the construction of additional homes in phases.

The paper discusses the plant performance before and after the improvements and describes how the improvements were implemented.

Document Type: Research Article


Publication date: January 1, 2005

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  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

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