Treatment of polyacrylamide production wastewater by multistage contact reactor with activated and anammox sludge

Abstract

Polyacrylamide (PAM) is extensively used in various fields and can often be detected in the corresponding wastewater. Some products can be slowly degraded to an acrylamide (AM) monomer naturally, which poses a threat to human health. In this study, three reactors with different structures were contrasted to investigate the ability to treat PAM production wastewater. Reactor 1 (R1), which was divided into 11 chambers, exhibited the best performance. After the start-up period, the multistage reactor could withstand the substrate shock load well. The changes in viscosity and organic nitrogen show that most of the PAM or AM were treated in R1. The chemical oxygen demand and NH4-N removal efficiency reached 96.4% and 97.2%, respectively. Meanwhile, simultaneous nitrification and denitrification was occurred in R1 and excess sludge production was much lower than the control reactors. Microbial analysis suggests that the independent chambers can form a unique bacterial community. This system could also promote the growth of anaerobic ammonium oxidation (anammox), which increased the total nitrogen removal efficiency to 80%.