Resilience of sulfate-reducing granular sludge against temperature, pH, oxygen, nitrite, and free nitrous acid

Abstract

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.

Removal of sulfamethoxazole (SMX) in sulfate-reducing flocculent and granular sludge systems

“…1). Thus, the SRB activity was not affected at the pH range of 6.0-9.0, which is in consistent with studies by Widdel et al (1983) and Hao et al (2016), who also reported that SRB activity did not change at pH range of 6.0-9.0. However, with decreasing influent pH from 7.0 to 6.0 in the SRUSB reactors, SMX removal gradually declined (Fig.…”

Mechanism and regulation of filamentous algal‐bacterial symbiosis based on microbiological quorum sensing

“…The above results indicate that exogenous AHLs have a significant effect on the EPS components of the algal‐bacterial symbiotic system, primarily by adjusting the LB‐EPS and TB‐EPS content. Additionally, the total polysaccharide content of the system changed (LB‐ and TB‐polysaccharide), indicating that the results of static experiments were a result of the quorum sensing regulatory mechanism (Hao et al, 2016; Xue et al, 2017). The initial response and positive induction were due to the extracellular polysaccharide secretion function.…”

Cadmium-containing Wastewater Induced by SRB: Effect of Multiple Ions and Mineralization Process

“…In recent years, the rapid development of the economy and the improvement of people's living standards pose a threat to the environment, especially heavy metal pollution has become a major obstacle to the aquatic environment [1,2] . As mining, metal smelting and electroplating industries directly discharge cadmium-containing acidic wastewater with high acidity, high Cd 2+ concentration, and high sulfate concentration, causing serious environmental pollution [3,4] .…”