Adsorption and effects of water-soluble acrylic acid-based polymers on activated sludge

Synthetic water-soluble polymers are used in agriculture, household cleaners, printing inks, lubricants, paints, adhesives, personal care products, and cosmetics. They often end up in wastewater, which is then treated in wastewater treatment plants before being released into the environment. In this study, we investigated the interactions and effects of synthetic water-soluble polymers, namely a homopolymer and a copolymer of acrylic acid, on activated sludge. The results showed that the homopolymer and copolymer were rapidly adsorbed on the activated sludge (˃70%) immediately after the initial contact and the adsorption process was described by the Freundlich isotherm model. The adsorption of copolymer affected the sedimentation rate of activated sludge. The endogenous and exogenous respiration of the activated sludge was not significantly affected by the presence of homopolymer or copolymer. However, their dose-response effect on exogenous respiration was observed. These results indicated that acrylic acid-based polymers can adhere to a high degree to activated sludge and thus also possibly to other biotic surfaces in the environment. Considering the large amount of synthetic water-soluble polymers released into the environment, their interactions and fate in the environment should be further investigated.