Conventional biological systems in centralized wastewater treatment plants (WWTPs) are presently inefficient in the removal of pharmaceutical and personal care products (PPCPs)

resulting in their ubiquitous presence in excess sludge by absorption. When the sludge is utilized in agricultural land

the absorbed PPCPs may be released and then water environment is contaminated. Therefore

it becomes a crucial issue to predict and assess the content of PPCPs in excess sludge

by revealing the controlling factors of PPCPs adsorption. The adsorption properties of three typical pharmaceuticals onto the sludge from a certain WWTP in Beijing

were investigated based on a trace concentration level using UPLC-MS-MS. The adsorption capacity of ciprofloxacin (CIP) and sulfamethoxazole (SMX) decreased

however

that of acetaminophen (ACP) increased with increasing pH; because the speciation of pharmaceuticals in aqueous solution and zeta potential of biosolid are as a function of pH. Extracellular polymeric substance (EPS) could enhance the adsorption of three typical pharmaceuticals onto the sludge

independent of pH; because the metal ions and organic substances contained in EPS determine the adsorption of pharmaceutical onto the sludge.