Influent:Wastewater
Denitrification system:Simultaneous Desulfurization and Denitrification (SDD)
Denitrifying reactor:Expanded granular sludge bed
Medium:nan
Culture taken from:Biogranule sludge
Organism (s) cultured:nan
Respiration:Anaerobic
Electron donor:Acetate
Electron acceptor:Nitrate
Input NO3-N (mg/l):10.3
Nitrate removal rate (mg NO3-N/l/h):9.6
Denitrification rate (gNO3-N removed/m3/day):nan
Microorganisms identified:Pseudomonas; Anaerobacter; Aminomonas; Levilinea; Clostridium; Sporanaerobacter; Thermothrix; Sulfurovum; Rikenella; Samsonia; Nitrincola; Idiomarina; Aminobacterium; Halalkalicoccus; Flavimonas; Chryseomonas; Xenohaliotis; Thermomicrobium
Molecular tools:16S amplicon sequencing; DGGE
Major findings:The research focused on denitrifying sulfide removal (DSR) test in an expanded granular sludge bed (EGSB) reactor, high sulfide concentration inhibited heterotrophic denitrifiers, and therefore the system accumulates nitrite. Autotrophic denitrifiers are then inhibited by the accumulated nitrite, this led to breakdown of the DSR process.
Authors:Chen et al., 2008
Title:Biological Breakdown of Denitrifying Sulfide Removal Process in High-Rate Expanded Granular Bed Reactor
Pubmed link:Link
Full research link:Link
Abstract:This work conducted a denitrifying sulfide removal (DSR) test in an expanded granular sludge bed (EGSB) reactor at sustainable loadings of 6.09 kg m?3 day?1 for sulfide, 3.11 kg m?3 day?1 for nitrate–nitrogen, and 3.27 kg m?1 day?1 for acetate–carbon with >93% efficiency, which is significantly higher than those reported in literature. Strains Pseudomonas sp., Nitrincola sp., and Azoarcus sp. very likely yield heterotrophs. Strains Thermothrix sp. and Sulfurovum sp. are the autotrophs required for the proposed high-rate EGSB-DSR system. The EGSB-DSR reactor experienced two biological breakdowns, one at loadings of 4.87, 2.13, and 1.82 kg m?3 day?1; reactor function was restored by increasing nitrate and acetate loadings. Another breakdown occurred at loadings of up to 8.00, 4.08, and 4.50 kg m?1 day?1; the heterotrophic denitrification pathway declined faster than the autotrophic pathway. The mechanism of DSR breakdown is as follows. High sulfide concentration inhibits heterotrophic denitrifiers, and the system therefore accumulates nitrite. Autotrophic denitrifiers are then inhibited by the accumulated nitrite, thereby leading to breakdown of the DSR process.