Simultaneous removal of ammonia and nitrate by coupled S0-driven autotrophic denitrification and Anammox process in fluorine-containing semiconductor wastewater

Highlights: • The effect of variable F⁻ concentration on Anammox activity was obviously. • The S⁰-Deamox process was realized by coupling Anammox, SSADN, and CSDAN processes. • The NH₄⁺ and NO₃⁻ in wastewater containing F⁻ were simultaneous removed by S⁰-Deamox. • S⁰-driven autotrophic denitrification process that reduces NO₃⁻ to NO₂⁻ was realized. • Candidatus Kuenenia, Thiobacillus and Sulfurimonas were main bacteria in S⁰-Deamox. -- Abstract: To achieve the simultaneous removal of NH₄⁺-N and NO₃⁻-N in F⁻-containing semiconductor wastewater by coupled S⁰-driven autotrophic denitrification and Anammox process, the effect of variable F⁻ concentration on the Anammox process was investigated by batch experiments. The denitrifying ammonium oxidation (Deamox) reactor was then started-up to explore the feasibility of the coupling of Anammox and sulfur autotrophic denitrification (SADN) for the treatment of semiconductor wastewater. Short-term variation of F⁻ concentration has an obviously effect on the activity of Anammox sludge, but didn't affect the nitrogen conversion rate. The activity of Anammox obviously decreased after long-term operation of the Deamox reactor when influent F⁻ concentrations reached 552 mg/L. The sensitivity of Anammox bacteria to F⁻ concentration is stronger than that of SADN bacteria. Total nitrogen removal efficiency of 98% and total nitrogen removal rate of 4.11 kg/(m³·d) were achieved in the Deamox reactor, when the F⁻ was pre-treated by calcium ions. Moreover, the high-throughput 16S rRNA gene sequence analysis indicated that variation in F⁻ concentrations could influence the structure and functional of microbial communities in the Deamox process. Candidatus Kuenenia, Thiobacillus and Sulfurimonas were main functional bacteria that achieved symbiotic.