Bioaugmentation of low C/N ratio wastewater: Effect of acetate and propionate on nutrient removal, substrate transformation, and microbial community behavior

The effect of various acetate/propionate ratios (1:0, 2:1, 1:1, 1:2, and 0:1) in a two-sludge A2/O - MBBR process was investigated. Results showed that the increased propionic/acetic ratios exerted indistinctive impact on COD (91.21–93.44%) and P (92.23–93.87%) removals, but high P content (7.42%) accelerated sludge granulation proved by SEM and EDS. Acetate favored N removal (79.52%−82.92%) with higher PURA (3.53–4.06 mgP/(gVSS·h)), while the...