Abstract
Due to toxicity inhibition and high external carbon costs, anaerobic/anoxic/oxic technologies for coking wastewater require efficient, low-carbon alternatives. Here we develop a strategy to effectively enhance the autotrophic nitrogen removal process in coking wastewater through a phased addition of diatomite porous material and an inorganic electron donor. Under long-term operation, diatomite increased biomass by 86% and induced micro-granular sludge with an average size of 196 μm. Nitrogen removal pathway analysis showed a shift from heterotrophic to autotrophic mode. Ultimately, SCN−– and FeS2-driven autotrophic denitrification contributed 25.6% and 27.9%, respectively. Enrichment of autotrophic sulfur-oxidizing nitrate-reducing bacteria, such as Sulfuritalea and Sulfurisoma, provided strong evidence. Additional pyrite supplementation ultimately increased total nitrogen removal from 77.7% to over 94.0% without external carbon. This study enhanced the in-situ autotrophic process of conventional systems for coking wastewater, offering a cost-effective pathway for energy-saving and carbon-reduction goals.
Funding
Huaqiang Chu discloses support for the research of this work from the National Natural Science Foundation of China [grant number 52270076].
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Ren, Z., Ma, J., Ding, P. et al. In-situ enhancement of autotrophic nitrogen removal in coking wastewater using staged diatomite and pyrite strategy.
Commun Eng (2026). https://doi.org/10.1038/s44172-026-00718-0
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DOI: https://doi.org/10.1038/s44172-026-00718-0
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