Membrane Filtration of Effluent from a One-Stage Bioreactor Treating Anaerobic Digester Supernatant

摘要: A challenge in side-stream treatment of anaerobic digester supernatant is that the effluent does not meet discharge standards. To address this challenge, study tested tubular multichannel ceramic microfiltration (MF) and ultrafiltration (UF) membranes for post-treatment supernatant. Pollutant rejection (total suspended solids (TSS), COD, total nitrogen (TN), phosphorus (TP)), color removal, membrane susceptibility to fouling were determined at various transmembrane pressures (TMPs) (0.2, 0.3, 0.4, 0.5 MPa). Both methods completely removed TSS. In MF, COD was with 48–76% efficiency 0.2–0.4 MPa. UF, removal slightly higher, reaching 83.7% 0.4 MPa. With both methods, pollutant did increase TMP 0.5 MPa. MF reduced by 54–100%, irrespective TMP. At 0.2–0.4 MPa, resistance lower permeate flux much higher than UF. 0.5 MPa, differed only from each other. Due larger cut-off, decline slower (0.7 h−1) UF (1.1 h−1), as pore-size favors less foulant deposition. Thus, taking into account efficiency, capacity, washing frequency, cost (pressure), these results indicate 0.4 MPa most effective variant variant, almost colorless contained 25 mg COD/L, no TSS, 55 mg TN/L (75% form nitrites nitrates), 8.5 mg TP/L, thus meeting criteria water be used irrigation or algae cultivation.