Degree Type


Date of Award


Degree Name

Doctor of Philosophy


Civil, Construction, and Environmental Engineering


An anaerobic filter is a column packed with highly porous material through which wastewater is passed, normally in an upwards manner. The reactor medium serves as a support for microorganisms which become attached to or otherwise retained within its interstitial pore spaces. As wastewater passes through the medium, the microorganisms decompose the organic materials in the wastewater and use them for growth and multiplication. The major by-products of this anaerobic reaction are methane and carbon dioxide gases;Whereas many aspects of anaerobic filter process have been investigated thoroughly, including its ability to handle high strength wastewaters, the effects of packing design and configuration on the degree of wastewater treatment have not been explored in much detail. The amounts of treatment attributed to attached bacterial growth and that attributed to suspended growth are not well-known;This study was designed to explore the effects of media design, size, and surface area on the performance of anaerobic filters. Four pilot-scale units measuring 0.51 m in diameter and 1.83 m in height were used. The units were packed with Pall rings, perforated spheres, and two sizes of corrugated modular media. The units were operated for 13 months at loading rates ranging from 0.5 to 16.0 gm COD/L-day, influent COD concentrations ranging from 1500 to 6000 mg/L, and a temperature of 30(DEGREES)C. The substrate was simulated grain alcohol production wastewater;The study results showed a strong correlation between media design and size and COD removal efficiency. Modular media which were associated with minimal short-circuiting resulted in substantially better treatment efficiencies than loose-fill media at all loading rates and influent waste concentrations. The study results also indicated that flocculated suspended solids within the media matrix were primarily responsible for organics removal. These results coupled with the results of biomass activity tests led to the conclusion that media specific surface area was not as critical a design parameter as is its "equivalent pore diameter.";A mathematical model was used to simulate the operation of the anaerobic filter system with emphasis on media related factors. The results suggest that the concept of media "equivalent pore diameter" is an effective approach to anaerobic filter media selection.



Digital Repository @ Iowa State University,

Copyright Owner

Mohamed Fituri Dahab



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235 pages