Resilience of sulfate-reducing granular sludge against temperature, pH, oxygen, nitrite, and free nitrous acid.
Sulfate-reducing granular sludge has recently been developed and characterized in detail as part of the development of the sulfate reduction, autotrophic denitrification, nitrification integrated (SANI) process. However, information regarding temperature of granules to environmental fluctuation is lacking, an aspect that is important in dealing with real wastewater. A comprehensive assessment of sulfate-reducing granular sludge performance under various environmental conditions was thus conducted in this study, including temperature, pH, oxygen, nitrite, and free nitrous acid (FNA) as possible encountering conditions in the removal of organics and/or nitrate. Specific chemical oxygen demand removal rate of the granules was determined to be reduced by 65 % when the temperature varied between 10-15 °C, reduced by 70 % when dissolved oxygen (DO) was 0.5 mg/L or greater, and at least, reduced by 75 % when nitrite was 30 mg N/L or above. Nevertheless, the sludge activity recovered by 82, 100, and 86 % from exposure to high oxygen and nitrite and low temperature levels, respectively. Combined inhibition of nitrite and FNA on the sludge is strong and complex, while FNA alone reduced cell viability from 60 to 40 % when its concentration increased to 2.3 mg N/L. The present study demonstrates that sulfate-reducing bacteria (SRB) granules possess high resilience against varying environmental conditions, showing the high application potential of sulfate-reducing granular sludge in dealing with brackish and saline industrial or domestic wastewaters.
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Tianwei
T
Hao
College of Science and Engineering, Hamad bin Khalifa University, Education City, Doha, Qatar.
Hamish R
HR
Mackey
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Gang
G
Guo
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Rulong
R
Liu
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong. ceghchen@ust.hk.|Water Technology Lab, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. ceghchen@ust.hk.|Hong Kong Branch of Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, HKUST, Clear Water Bay, Hong Kong, China. ceghchen@ust.hk.
Guanghao
G
Chen
D057919:Biological Oxygen Demand Analysis; D006863:Hydrogen-Ion Concentration; D059013:Microbial Consortia / Q000187:drug effects* / Q000528:radiation effects*; D009573:Nitrites / Q000378:metabolism; D009608:Nitrous Acid / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D012722:Sewage / Q000382:microbiology*; D013431:Sulfates / Q000378:metabolism*; D013696:Temperature; D018508:Water Purification / Q000379:methods
D009573:Nitrites; D012722:Sewage; D013431:Sulfates; D010100:Oxygen; D009608:Nitrous Acid
Adaptability; Granular sludge; SANI process; Sulfate-reducing bacteria