Determination of Denitrification Kinetics for Methanol Utilizing Bacteria
Open AccessTo meet new stringent effluent nitrogen limits, wastewater treatment facilities need accurate kinetic parameters to effectively achieve design objectives. Denitrification process optimization depends on treated effluent limits, but most importantly on the capabilities of an efficient system. Blue Plains Advanced Wastewater Treatment Plant (AWTP) in Washington, DC, the largest point source in the Chesapeake Bay area, utilizes methanol addition for denitrification. To improve the performance of its nitrogen removal processes, advanced research was necessary to elucidate the kinetics and stoichiometry of methanol utilizing bacteria (methylotrophs) in both anoxic and aerobic zones of denitrification reactors. This study focuses on the determination of the anoxic half saturation coefficient (KSCOD), for methanol, since anoxic denitrification tank volume requirements are dependent on KSCOD. Aerobic KSCOD tests were also performed in order to understand the performance of methylotrophs in the post anoxic, aerobic reactor in the Blue Plains denitrification reactors. Experiments were conducted to determine parameters such as specific denitrification rates (SDNR), specific methanol consumption rates (SMCR), yield and carbon to nitrogen ratios (C:N). A method was developed to measure low methanol concentrations using Gas Chromatographic (GC) analysis. The anoxic methanol KSCOD varied over a range from 0.13 to 2.35 mg COD/L, and the aerobic methanol KSCOD varied over a range from 1.41 to 15.71 mg COD/L. The stoichiometric methanol C:N estimated in the study for the anoxic tests was 5.29 mg COD/mg NO3-N and the average yield was 0.45 mg biomass COD/mg NO3-N. Also for the anoxic experiments, the SDNR values were between 3.5 and 12.9 mg NO3-N/g MLVSS-hr and SMCR was estimated to be between 21.2 and 65.2 mg CH3OH/g MLVSS-hr, both increasing with temperature. A linear correlation was found between anoxic SMCR and SDNR. Meanwhile, SMCR for aerobic test was estimated to be between 46.8 and 84.5 mg CH3OH/g MLVSS-hr, considerably higher than the SMCR for anoxic experiments. This information can be used to design and operate plants that handle methanol dosing in an optimal way.
- All rights reserved
Notice to Authors
If you are the author of this work and you have any questions about the information on this page, please use the Contact form to get in touch with us.
| Thumbnail | Title | Date Uploaded | Visibility | Actions |
|---|---|---|---|---|
|
|
TorresOrtiz_gwu_0075M_11668.pdf | 2018-01-16 | Open Access |
|