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Cost Effective Secondary Clarification of UASB Reactor Effluent with the Biothane Dissolved Air Flotation Process at a Juice Manufacturing Plant

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Clement Pappas & Company, Inc. installed an UASB process in 1993 to pretreat its wastewater prior to discharging it into the city sewer. The UASB process removed more than 90% of the wastewater COD which resulted in substantial savings in sewer surcharges. In 1997 the Cumberland County Utilities Authority revised its surcharge schedule to include both BOD and suspended solids (TSS). In order to further reduce its effluent surcharges, the Dissolved Air Flotation (DAF) process available from Biothane Corporation was evaluated and implemented.

This paper provides an overview of the on-site jar and flotation tests that were conducted as part of the DAF evaluation process. It was found that a single cationic flocculant could effectively flocculate the TSS which could successfully be separated through flotation. The TSS in the UASB reactor effluent was reduced from 691 mg/l to 53 mg/l while the COD was reduced by 63%.

Based on the positive bench test results, Clement Pappas decided to install a DAF system in 1999 to further treat the UASB reactor effluent before it is discharged into the city sewer. Since its installation, the DAF was able to consistently reduce the anaerobic effluent TSS to less than 100 mg/l through the use of chemicals. The float produced by the DAF system varied between 13 and 16%, which lowered the sludge volume and reduced its disposal cost to a minimum. Due to the substantial savings in surcharges that resulted from the TSS and TCOD removal, the DAF system had a payback of less than one year.

Document Type: Research Article


Publication date: January 1, 2000

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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 These proceedings are not peer reviewed.

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