Effect of influent volumetric loading on extracellular polymeric substances

To improve the efficiency of sewage treatment, the effect of influent volumetric loading on the extracellular polymeric substances(EPS) of sludge is investigated using a sequencing batch reactor activated sludge process. The fluorescence analysis of EPS is proceeded using a three-dimensional fluorescence spectrum(Jasco FP-6500). The results show that the EPS concentration is 70~80 mg/L when the influent volumetric loading is 8.63 kg COD/(m3·d), and two clear protein-like fluorescence absorption peaks are observed using the three-dimensional fluorescence spectrum analysis. When the influent volumetric loading is 18.5 kg COD/(m3·d), the concentrations of EPS, protein and polysaccharide are(89.52±0.46) mg/L, 26.45~28.9 mg/L and(9.38±0.35) mg/L, respectively, and the strength of fluorescence peaks increases obviously. Higher volumetric loading leads to higher EPS concentration, and the composition of EPS is not changed. When the influence volumetric loading is 3.73 kg COD/(m3·d), the concentrations of EPS, protein and polysaccharide are(69.8±1) mg/L, 22.02~29.05 mg/L and(5.34±0.6) mg/L, respectively, and the strength of fluorescence peaks is weak. Lower influent volumetric loading leads to lower EPS concentration.