Granular Sludge Coupling Nitrate/Nitrite Dependent Anaerobic Methane Oxidation with Anammox: from Proof-of-Concept to High Rate Nitrogen Removal

摘要

This work developed a novel Membrane Granular Sludge Reactor (MGSR) equipped with a gas permeable membrane module for efficient methane delivery to cultivate nitrateitrite dependent anaerobic methane oxidation (n-DAMO) microorganisms in granular sludge. As proof of concept, the MGSR was fed with synthetic wastewater containing nitrate and ammonium to facilitate the growth of n-DAMO microorganisms. The granular sludge of n-DAMO and Anammox was gradually developed and achieved a nitrogen removal rate of 1.08 g NO_3~- -N L~(-1) d~(-1) and 0.81 g NH_4~+-N L~(-1) d~(-1), Finally, enriched granular sludge was successfully applied for nitrogen removal from the synthetic partial nitritation effluent. The combined dominance of n-DAMO archaea, Anammox bacteria, and n-DAMO bacteria in the microbial community was confirmed by 16S rRNA amplicon sequencing. Fluorescence in situ hybridization revealed that a layered structure was formed in the granular sludge with Anammox bacteria in the outer layer and n-DAMO microorganisms in the inner layer when granules were fed with nitrite and ammonium. The high performance of nitrogen removal (16.53 kg N m~(-3) d~(-1)) with satisfactory effluent quality (~8 mg N L~(-1)) and excellent biomass retention capacity (43 g VSS L~(-1)) make the MGSR promising for the practical application of n-DAMO and Anammox in wastewater treatment.