A review in Fe(0)/Fe(Ⅱ) mediated autotrophic denitrification for low C/N wastewater treatment.

Fe-mediated autotrophic denitrification has emerged as a promising technology for low carbon-to-nitrogen (C/N) wastewater treatment due to its cost-effectiveness, operational safety, and independence from organic carbon. While several reviews have addressed this process, there is still a lack of comprehensive analyses that connect iron materials, denitrification performance, and microbial communities. The practical applicability of solid-phase iron has received little attention, and the key controversial issue - Fe(Ⅱ) oxidation pathway - has not been specifically examined.

Microbial transitions and degradation pathways driven by butyrate concentration in mesophilic and thermophilic anaerobic digestion under low hydrogen partial pressure.

Butyrate accumulation significantly affects the efficiency and stability of anaerobic digestion, while its specific impact on methane yield and butyrate degradation remains unclear. This study investigated how butyrate concentrations (2.0, 5.

Unacclimated activated sludge improved nitrate reduction and N selectivity in iron filling/biochar systems.

Iron (Fe)-based denitrification is a proven technology for removing nitrate from water, yet challenges such as limited pH preference range and low N selectivity (reduction of nitrate to N) persist. Adding biochar (BC) can improve the pH preference range but not N selectivity. This study aimed to improve nitrate reduction and N selectivity in iron filling/biochar (Fe/BC) systems with a simplified approach by coupling unacclimated microbes (M) in the system.

Integration of anaerobic digestion and electrodialysis for methane yield promotion and in-situ ammonium recovery.

Ammonia inhibition is a common issue encountered in anaerobic digestion (AD) when treating nitrogen-rich substrates. This study proposed a novel approach, the electrodialysis-integrated AD (ADED) system, for in-situ recovery of ammonium (NH) while simultaneously enhancing AD performance. The ADED reactor was operated at two different NH-N concentrations (5,000 mg/L and 10,000 mg/L) to evaluate its performance against a conventional AD reactor.

17β-estradiol (E2) removal in anode-electrodialysis (anode-ED) during nutrient recovery from pig manure digestate.

Nutrient recovery from anaerobic digestate through electrodialysis technology (ED) has been investigated and shown high promise, but the removal of 17β-estradiol (E2), which is a natural estrogen and widely found in manure digestate, is not clear. This study examined the mechanism of membrane adsorption and anodic oxidation of E2 during recovering nutrient from manure digestate, and further investigated the performance of Anode-ED in E2 removal. The results showed that the removal of E2 in conventional ED was primarily attributed to membrane adsorption, resulting in no detectable E2 in the product solution.

Nitrate removal in iron sulfide-driven autotrophic denitrification biofilter: Biochemical and chemical transformation pathways and its underlying microbial mechanism.

Iron sulfides-based autotrophic denitrification (IAD) is effective for treating nitrate-contaminated wastewater. However, the complex nitrate transformation pathways coupled with sulfur and iron cycles in IADs are still unclear. In this study, two columns (abiotic vs biotic) with iron sulfides (FeS) as the packing materials were constructed and operated continuously.