Date Approved

4-29-2002

Embargo Period

5-18-2016

Document Type

Thesis

Degree Name

M.S. in Engineering

Department

Civil & Environmental Engineering

College

Henry M. Rowan College of Engineering

First Advisor

Jahan, Kauser

Subject(s)

Autotrophic bacteria; Environmental chemistry

Disciplines

Civil and Environmental Engineering

Abstract

This research focused on the novel use of hollow fiber membranes for gas delivery in biological dentrification using hydrogen-oxidizing bacteria. Autotrophic denitrification is a biological process that reduces nitrate to nitrogen gas using an inorganic carbon source. Hydrogen gas is an electron donor and nitrate is the electron acceptor in the reaction. The specific research objectives were to:

  • develop a mixed acclimated culture of hydrogen-oxidizing bacteria;
  • evaluate biodegradation kinetics of the acclimated culture;
  • evaluate hydrogen transfer characteristics of hollow fiber membrane modules;

and

  • demonstrate technical feasibility of a continuous bioreactor-membrane system for denitrification.

The following kinetic coefficients were obtained: µm of 0.65 d-1, Y of 0.78 mg cells/mg NO3-N, and kd of 0.04 d-1. The nitrate utilization rate was determined to be 1.0 mg NO3-N/mg biomass. The following mass transfer correlation can be used to design membrane modules for hydrogen dissolution into water:

Sh = 2.68 Rede/L1.02Sc0.33

Continuous flow studies indicate that a stable biofilm can be developed in a packed bed reactor to remove nitrate using hydrogen as the electron donor. Hydrogen gas was successfully delivered to the reactor via the hollow fiber membrane gas transfer module without fouling. Dissolved hydrogen concentrations indicate that the system did not experience hydrogen limitations. Membrane gas delivery appears to be a viable technology for transferring hydrogen to water for autotrophic denitrificiation.

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