A Novel Strategy to Reduce the Higher Nitrogen Loading Shock on Anammox Growth Rate and Granule Sludge Stability

Effects of different electric field intensities on the anammox process were investigated. The results showed that the suitable electric field intensity could dramatically enhance the anammox growth rate and granule sludge stability under a higher nitrogen loading shock. The cellular yield and anammox amount of R2 (0.3 V/cm) was significantly enhanced by 186.48%, 183.79%, 146.51%, 131.26%, and 430%, 440.23% than that of R1 (control group), R3 (0.6 V/cm), and R4 (0.9 V/cm), with a nitrogen loading rate of 11.60 kg-N/(m³∙day). Besides, the electric field could stimulate cells to secrete more EPS to resist higher nitrogen loading shock. The protein (PN)/polysaccharide (PS) ratios of R2 were 22.22%, 16.44%, and 36% higher than those of R1, R3, and R4, which was beneficial to granule sludge stability. This study showed that electric field intensity could solve the problem of lower anammox growth rate and granule stability under a higher nitrogen loading shock.