Date of Award

7-1987

Document Type

Graduate Project

Degree Name

Master of Engineering (ME)

Abstract

Bench-scale treatability research conducted at the University of North Dakota Sanitary Engineering Laboratory demonstrated that the coupled, downflow, biological fluidized bed process was an effective system for the treatment of synthetic fuels processing wastewater. In the biological fluidized bed process the nitrification and denitrification columns were coupled to nitrify ammonia to nitrite and/or nitrate, and then to denitrify nitrite and/or nitrate to nitrogen gas, in addition to the breakdown of carbonaceous and organic nitrogen. The wastewater used in the research was generated by the Great Plains Coal Gasification Plant located at Beulah, North Dakota. The two fluidized bed reactors contained six inches of filtered unfluidized macrospheres. The macrospheres were found to have an effective size of 0.47mm and a specific gravity of 0.40. The flow velocities through the columns at steady-state period were 0.238 cm/sec (0.0935 in/sec) and 0.128 cm/sec (0.050 in/sec) for nitrification and denitrification reactors respectively.

A mean ammonia concentration of 700 mg/1 was nitrified and denitrified (62.5% removal) from the undiluted GPGP SGL wastewater in a total system HRT of 1.06 days. On the overall, BOD was reduced from 1249.9 mg/1 to 242.7 mg/1 (80.6%), COD from 2475.5 mg/1 to 743.9 mg/1 (70.0%), and TOC from 664.5 mg/1 to 178.0 mg/1 (73.2%), at a feed rate of 4.5 L/d. The system performance improved considerably upon approaching steady-state conditions. The steady-state removals were 80.3% for ammonia, 80.7% for BOD, and 88% for COD at a 4.5 L/d feed rate.

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