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

Authors :
Jiang Xu
Zhikun Lu
Yifeng Xu
Chuanzhou Liang
Lai Peng
Source :
Water, Vol 16, Iss 5, p 730 (2024)
Publication Year :
2024
Publisher :
MDPI AG, 2024.

Abstract

Sulfur-driven autotrophic denitrification (SADN) has demonstrated efficacy in nitrate (NO3−) removal from the aquatic environment. However, the insolubility of elemental sulfur (S0) (maximum 5 μg/L at 25 °C) limited the NO3− removal rate. In this study, we investigated the performance of a laboratory-scale S0-packed bed reactor (S0-PBR) under various volumetric NO3− loading rates. By filling with smaller S0 particles (0.5–1 mm) and introducing chemical sulfide (30–50 mg S2−-S/L), a high NO3− removal rate (1.44 kg NO3−-N/(m3·d)) was achieved, which was substantially higher than previously reported values in SADN systems. The analysis of the average specific NO3− removal rates and the half-order kinetic constants jointly confirmed that the denitrification performance was significantly enhanced by decreasing the S0 particle sizes from 10–12 mm to 1–2 mm. The smaller S0 particles with a larger specific surface area improved the mass-transfer efficiency. Dosing chemical S2− (20 mg S2−-S/L) to trigger the abiotic polysulfuration process increased the specific NO3− removal rate from 0.366 to 0.557 g NO3−-N/g VSS/h and decreased the portion of removed NO3−-N in the form of nitrous oxide (N2O-N) from 1.6% to 0.7% compared to the S2−-free group.

Details

Language :
English
ISSN :
20734441
Volume :
16
Issue :
5
Database :
Directory of Open Access Journals
Journal :
Water
Publication Type :
Academic Journal
Accession number :
edsdoj.f33cd1d32c4ca298d9a65d1c8e6e5c
Document Type :
article
Full Text :
https://doi.org/10.3390/w16050730