Browsing by Author "Lee, Po-Heng"

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Insights into the roles of anammox bacteria in post-treatment of anaerobically-treated sewage
(2018-01-01)
Wang, Qian
;
Tan, Giin-Yu Amy
;
Azari, Mohammad
;
Huang, Xiaowu
;
Denecke, Martin
Complete anaerobic treatment of sewage has the potential to achieve net energy production via capturing the energy of organics in sewage, but not nitrogen, which remains a concern. Anaerobic ammonium oxidation (anammox) is potential for energy-efficient nitrogen removal from anaerobically-treated sewage. Given the sensitivity of anammox bacteria and the challenge of the low ammonium-bearing influent with reduced compounds such as volatile fatty acids, methane, and sulfide, this article critically reviewed and analyzed, using thermodynamic computation as a tool, the potential interactions of anammox bacteria with other microbes induced by the reduced compounds in anaerobically-treated sewage. The dynamics of anammox bacteria to cooperate with these microbes that metabolize non-ammonium pollutants and to outcompete for the common substrate, i.e., nitrite, are extensively discussed. The versatile metabolism of anammox bacteria on volatile fatty acids and iron, which would help facilitate the treatment efficiency, was also reviewed. The information offered in this review will be beneficial to researchers and engineers in controlling process stability, enhancing total nitrogen removal, and achieving better effluent quality in post-treatment of anaerobically-treated sewage by anammox-based processes.
Simultaneous partial nitrification, anaerobic ammonium oxidation and denitrification (SNAD) in a full-scale landfill-leachate treatment plant
(2010-03-15)
Wang, Chih-Cheng
;
Lee, Po-Heng
;
Kumar, Mathava
;
Huang, Yu-Tzu
;
Sung, Shihwu
The occurrence of simultaneous partial nitrification, anaerobic ammonium oxidation and denitrification (SNAD) observed in a single Partially aerated full-scale bioreactor treating landfill-leachate is reported in his paper. At present, the full-scale bioreactor is treating an average leachate flow of 304 m(3) d(-1) with a sludge retention time between 12 and 18 d. The average COD, NH(4)(+)-N and NO(3)(-)-N concentrations at the upstream end of the bioreactor. i.e., influent, are 554, 634 and 3 mg L(-1), respectively; whereas no NO(2)(-)-N is detected in the influent. The percentage removals of COD and NH(4)(+)-N in the bioreactor were 28% and 80%, respectively. A nitrogen mass balance approach was adopted to analyze the performance of SNAD in the full-scale bioreactor. The total nitrogen (TN) removal by combined partial nitrification and anaerobic ammonium oxidation is 68% and the heterotrophic denitrification contributes to 8% and 23% of TN and COD removals, respectively. The red granule in the bioreactor was analyzed by using fluorescence in situ hybridization and polymerase chain reaction. The results of both analytical methods confirm the presence of anaerobic ammonium oxidizing bacteria as the predominant species along with other Planctomycete-like bacteria. Overall, the SNAD process offers the simultaneous removals of nitrogen and COD in the wastewater. (C) 2009 Elsevier B.V. All rights reserved.