Organic Carbon and Nitrogen Removal from Nylon-6 Wastewater Using an A/O1/O2 BiOfilm System

The aerobic reactor of A/O process was separated into two segments and each of them was installed with conjugate fibre packing, which was formed into an A/O(1)/O(2) biofilm system, In the A/O(1)/O(2) biofilm system, organic carbon degradation and nitrogen removal from nylon-6 wastewater in each reactor were investigated. Furthermore, infrared spectroscopy was selected for analyzing substrates decomposition. Results showed that good performance of the A/O(1)/O(2) biofilm system was achieved and average removal efficiencies of COD, NH(4)(+)-N and TN were 93%, 85% and 59%, respectively. When organic loadings varied from 1.64 kg.m(-3).d(-1) to 4.61 kg.m(-3).d(-1), different removal variations of COD, NH(4)(+)-N and TN were obtained in reactors A, O(1) and O(2). As for COD removal, average contribution ratios of reactors A, O(1) and O(2) were 63%, 30% and 4%, respectively. Referring to NH(4)(+)-N removal, average contribution ratios of reactors O(1) and O(2) were 24% and 76%. And regarding TN removal, average contribution percentages of reactor A, O(1) and O(2) were 75%, 20% and 4%, respectively. Investigation on the infrared spectroscopy of each wastewater sample demonstrated that in the progress of substrates degradation, the contents of amino acid, the amide and aliphatic compounds decreased, but the contents of NH(4)(+), NO(3)(-), HCO(3)(-) and carbohydrate increased.