Application of osmotic pump coupled solid phase extraction samplers for the on-site sampling and enrichment of pharmaceuticals and personal care products in wastewater treatment plants

In assessing the occurrence and fate of pharmaceuticals and personal care products (PPCPs) in wastewater treatment plants (WWTPs), their time-weighted average concentrations are highly desirable. Therefore, the development of composite sampling techniques that are suitable for on-site wastewater deployment, cost-effective, and independent of external power sources is imperative. In this study, an osmotic pump coupled solid phase extraction (OP-SPE) sampler was employed to collect samples for monitoring 14 PPCPs in WWTPs. Results showed that the PPCP recoveries by using OP-SPE samplers ranged from 40.36 % (enrofloxacin) to 115.93 % (fenoprofen), while the method quantification limits ranged from 0.15 ng/L (trimethoprim) to 3.18 ng/L (enrofloxacin). Good reproducibility was observed with relative standard deviation values of all analytes less than 20 %. The OP-SPE method achieved comparable performance in terms of recovery, repeatability, reproducibility, method detection limits, and method quantification limits, when compared to the widely adopted mixed grab samples and offline SPE pretreatment method. Eleven and fourteen PPCPs were detected in the influent and effluent, respectively. Based on the time-weighted average concentrations, the total daily mass loads of the dissolved PPCPs were 135.69 g/d in the influent and 16.03 g/d in the effluent. The OP-SPE sampler integrates in-situ sampling, filtration, enrichment, and purification, thereby minimizing the degradation of PPCPs due to microbial activity. Overall, the OP-SPE sampler has the potential to serve as a robust tool for capturing the time-weighted average concentrations of PPCPs in WWTPs, enabling estimation of mass loads and their reduction through the wastewater treatment processes. • A new sampler for continuous sampling of PPCPs in WWTPs. • Good agreement between OP-SPE and mixed grab samples with offline SPE pretreatment. • The OP-SPE sampler is cost-effective, compact, reusable, and operates without requiring an external power. • Obtaining data on PPCPs with time-weighted average concentrations.