Mitigating nitrite accumulation during S0-based autotrophic denitrification: Balancing nitrate-nitrite reduction rate with thiosulfate as external electron donor

Improved Performance of Sulfur-Driven Autotrophic Denitrification Process by Regulating Sulfur-Based Electron Donors

“…Comparatively, the residual NO 3 − concentrations were approximately 16 mg NO 3 − -N/L and 12 mg NO 3 − -N/L at 12 h in the groups with the S 0 particle sizes of 10-12 and 7-9 mm, respectively. Meanwhile, as a result of a lower NO 2 − reduction rate and faster NO 3 − reduction rate, the build-up of NO 2 − was gradually formed in all groups (Figure 2b), which was consistent with points that the capability of electron-scavenging for nitrite reductase was weaker than nitrate reductase [59,60].…”

“…The aggravated NO 2 − accumulation in the S 2− -added group resulted from the imbalance rate of the NO 3 − and NO 2 − reduction process, and the imbalance could be attributed to two main reasons. Firstly, the extent of NO 2 − accumulation was positively correlated with the NO 3 − reduction rate [60]. It can also be noticed that the NO 3 − removal rate was faster in the S 2− -added group (Figure 3a,b) due to the presence of S n 2− , which explained the severe NO 2 − accumulation well.…”

Treatment of nitrate-contaminated groundwater using microbially enhanced permeable reactive barrier technology

“…At present, many scholars have also confirmed that Thiobacillus and Sulfurimonas play a major role in the nitrogen removal in S 0 -based reactors. 40–42 As shown in the results in Table 3, the content of S 0 in the SSS and SWC reactors decreased obviously, which further demonstrated that Thiobacillus and Sulfurimonas played a vital role in the SAD process. Therefore, sulfur autotrophic bacteria mainly composed of Sulfurimonas and Thiobacillus were formed in the SSS and SWC reactors, which played an important role in the removal of NO 3 − -N. In the SW and SC reactors, there was no particular dominant group of microorganisms at the genus level.…”

Thermodynamic Inhibition of Microbial Sulfur Disproportionation in a Multisubunit Designed Sulfur-Siderite Packed Bioreactor

“…S 2 PB Operation. In the lab-scale investigation, three S 2 PBs were operated with a constant EBCT time of 0.5 h. The influent nitrate-nitrogen concentration was consistently reduced from approximately 15 mg-N/L to below 1 mg-N/L in the three S 2 PBs, each at temperatures of 30, 20, and 10 °C, respectively. During an 80-day operational period, samples of influent and effluent were collected to measure concentrations of DO, nitrate, nitrite, and dissolved sulfide.…”

“…Elemental sulfur (S 0 ) is among the most prevalent sulfur species in nature, formed through biological and chemical oxidation of sulfide . Owing to its low valence state, indicating a significant availability of donatable electrons, S 0 has been extensively utilized as an electron donor for sulfur autotrophic denitrification (S 0 AD) in the wastewater treatment process. − Taking into account the acidogenic characteristic of the S 0 AD process, we combined siderite, an alkaline mineral, with sulfur to construct sulfur-siderite packing bioreactors (S 2 PBs), which successfully achieved a substantial improvement in S 0 AD performance . As a result, this approach offers significant advantages, including independence from organic carbon, lower operational costs, and zero carbon dioxide emissions, while demonstrating impressive nitrate removal capabilities. , …”