The Influence of Temperature Changes in Activated Sludge Processes on Ibuprofen Removal Efficiency

Abstract

The article presents results regarding the ibuprofen reduction rate at three various temperature values (8, 18 and 28 °C) which were conducted using a static test in accordance with the PN-C-04645 'Water and wastewater. Evaluation of partial biodegradation of anionic and non-ionic surface active substances. Initial test' standard. A single study cycle including the analysis of ibuprofen degradation rate in specific temperature variants lasted 24 h. The activated sludge for tests was obtained from the aeration zone of a bioreactor localized in the Central Wastewater Treatment Plant in Poznan City (Poland), which was used for inoculation (1 g/dm3) of sterile samples with the medium and ibuprofen (10 mg/dm3) after appropriate pre-treatment (intense aeration for 5 h). The analysis procedure included the separation and concentration of analytes from biodegradation samples by means of solid phase extraction (SPE) and subsequent determination with high performance liquid chromatography coupled with mass spectrometry (LC-MS/MS) using an UltiMate 3000 RSLC liquid chromatogram (Dionex, USA) with a tandem API 4000 QTRAP mass spectrometer (Biosystem, MDS Sciex, USA). Both literature review as well as the conducted initial studies confirmed that the removal of ibuprofen proceeds more rapidly at higher temperature values. A higher retention rate also enhanced the reduction of ibuprofen concentration. A decrease of its concentration was observed after 24 h, which reached 40 and 50 % for temperature values of 8 and 18 °C, accordingly, whereas the highest reduction by approx. 65 % was noted at 28 °C.