High-rate treatment of polyester fabric alkali-peeling process wastewater

The polyester fabric alkali-peeling process wastewater was a new kind of textile industrial wastewater. Acidification-sedimentation and biological treatment system were employed to treat the wastewater. The biological treatment system consisted of hydrolysis-acidification bioreactor (HABR) and hybrid membrane bioreactor (HMBR). In acidification-sedimentation experiment, TA in wastewater decreased sharply from 19800 mg.L-1 to 2750 mg.L-1 with a removal rate of 86%, which greatly reduced the load of following biological treatment. The biodegradability of wastewater decreased after TA was recovered from raw wastewater by acidification-sedimentation. The value of BOD5/COD decreased from 0.37-0.40 to 0.27-0.31. In biological treatment experiment, when the influent COD was 2109 mg.L-1 and TA was 524 mg.L-1, the total removal rate of COD and TA were beyond 97% and 99%, respectively. It came to a conclusion that TA was easily biodegraded in aerobic HMBR and poorly biodegraded in anaerobic HABR. Only 2.3% TA was biodegraded in anaerobic HABR, while up to 97% TA was biodegraded in aerobic HMBR. However, about 29.8% and 67% COD were removal in HABR and HMBR, respectively.