Experimental Research On The Treatment Of Low-Degradability Printing And Dyeing Wastewater With Hydrolytic Acidification-Aerobic Biological Contact Oxidation Processes

This experiment is focused on the printing and dyeing wastewater with low bio-degradability and high PH, which is taken from real engineering project.The experiment research shows that it is technical feasible to treat printing and dyeing wastewater with the process of hydrolytic acidification - biological contact oxidation - biological carbon - fibre ball filter. During the stable operation period the average COD removal efficiency was 84.8%. The corresponding maximal COD lord of the system was 2.59 kg/m3.d and the minimal HRT was 16.4hr.The stage one & stage two hydrolytic acidification could increase the BODs/COD ratio from 0.16 to 0.35 and 0.44 respectively, thus greatly improved the bio-degradability of the wastewater. At the same time the hydrolytic acidification processes could resist PH variation and greatly decrease PH volume of the wastewater. With the average influent PH=10.4, the effluent PH of the stage one and stage two decreased PH to 9.2 and 8.4 respectively, created a good PH condition for the following aerobic treatment.The stage one & stage two aerobic biological contact oxidation contribute most of the COD removal of the experimental process. The COD removal efficiency of the two aerobic contact oxidation treatment stages was 29.4% & 20.8% respectively, accounting for 66% of the total COD removal efficiency of the system.The removal efficiency of colority and SS is 82.1% and 81.3% respectively. The average colority and SS of the effluent was 46 and 30mg/l respectively, both were superior to the grade one discharge criterion.