Start-up of Anammox systems with different biochar amendment: Process characteristics and microbial community

Rapid Start-Up and Long-Term Stability of Anammox with Magnetic Biochar Addition: Performance Improvement, Microbial Community, and Potential Mechanisms

“…The start-up phase can be separated into three steps based on the concentration of NH 4 + –N in influent and effluent: (I) the bacterial hydrolysis period (effluent NH 4 + –N higher than influent); (II) the activity improvement (effluent NH 4 + –N gradually decreased, effluent NO 2 – –N gradually increased and then decreased); (III) the stable operation period (synergistic removal of NH 4 + –N and NO 2 – –N in proportion to each other). Several researchers also described the distinct steps of the start-up process. , …”

“…Several researchers also described the distinct steps of the start-up process. 4,16 In the bacterial hydrolysis period, organic nitrogen release by microbial dissolution resulted in effluent NH 4 + −N being higher than the influent. Meanwhile, the organic matter produced by bacterial hydrolysis was used as a carbon source by heterotrophic denitrifying bacteria, leading to the continuous removal of NO 2 − −N during this period.…”

“…6 The start-up of anammox was accelerated by the addition of 5% coconut biochar to the reactor in only 46 days, compared to 69 days for the blank reactor, and the biochar addition significantly promoted the proliferation of Candidatus brocadia and Candidatus jettenia. 4 The addition of biochar as an electron shuttle to the UASB reactor shortened the establishment of the anammox reactor from 121 days (R0) to 85 days (R1) and 90 days (R2), while the nitrogen removal rates of R1−R2 were improved by 9.3 and 14.7% compared with R0. 7 Meanwhile, quinone and phenolic functional groups on the surface of biochar could regulate the electron-transfer pathway, promote the reduction of NO 3 − −N, and alleviate the inhibition of anammox by high concentrations of NO 2 − −N (600 mg N L −1 ).…”

“…Compared to traditional nitrification–denitrification processes, anammox offers great economic benefits such as no additional organic carbon, aeration saved by 62.5%, and low energy consumption . Nevertheless, anammox reactor start-up usually takes a long time, as AnAOB grows slowly, doubling ploidy times are long at 7–20 days, and has a low cell yield at 0.066 ± 0.010 mol C/mol NH 4 + , Particularly, the sludge is easily washed away with the effluent, making the enrichment of AnAOB problematic during the practice period. Hence, it is critical to accelerate the anammox start-up process, promote the enormous enrichment of AnAOB, and ensure the appropriate operation of the anammox reactor, for which many research efforts are being made, including adding biochar.…”

“…Biochar, a waste byproduct with a fine pore structure and large surface functional groups, has been widely applied in wastewater biological treatment processes . The start-up of anammox was accelerated by the addition of 5% coconut biochar to the reactor in only 46 days, compared to 69 days for the blank reactor, and the biochar addition significantly promoted the proliferation of Candidatus brocadia and Candidatus jettenia . The addition of biochar as an electron shuttle to the UASB reactor shortened the establishment of the anammox reactor from 121 days (R0) to 85 days (R1) and 90 days (R2), while the nitrogen removal rates of R1–R2 were improved by 9.3 and 14.7% compared with R0 .…”