Degradation of widespread pharmaceuticals by activated sludge: Kinetic study, toxicity assessment, and comparison with adsorption processes

Abstract

The growing presence of pharmaceutical compounds in aqueous systems leads to the search for new efficient and eco-friendly solutions to this problem. Although pharmaceutical products are widely found in the aqueous environments, there is limited understanding of their ecological effects. To augment the removal of pharmaceuticals, a bench reactor was inoculated with activated sludge and fed with a synthetic medium. Two pharmaceuticals of widespread usage, ibuprofen (IBU) and paracetamol (PARA) in the range 0.4-1 mg L -1 were used. The uptake values increased from 0.192 to 0.660 mg g -1 for IBU and from 0.104 to 0.341 mg g -1 for PARA. The removal efficiency reached values from 99.1-99.5 % and is independent of the initial IBU concentration. For PARA the removal percentage ranged from 93.3-98.8 decreasing with the increase on the initial concentration. The removal mechanism is well described by pseudo-first order and pseudo-second order kinetic models for all concentrations tested. At same time, batch assays were performed in order to assess the toxicity of both pharmaceuticals into the activated sludge using quantitative image analysis (QIA). For IBU experiments, QIA studies showed that this compound favors the growth of aggregated biomass rather than filamentous bacteria. A comparison between this biological technology and adsorption by a commercial porous ceramic material and Pinus bark was also performed. The results showed that the biological technology allowed better results (99.5 % against 19.4 and 9.3 %, respectively for the ceramic material and Pinus bark) for IBU. The results obtained for PARA showed comparable results for the biological technology and for adsorption by the ceramic material. The activated sludge system presented here appears to be a promising treatment for pharmaceutical contaminated effluents and the biomass present in the activated sludge seems do not be negatively affected by the presence of high concentrations of both pharmaceuticals.

Effect of ibuprofen on extracellular polymeric substances (EPS) production and composition, and assessment of microbial structure by quantitative image analysis

“…The correlations suggest that EPS and its components significantly influence aggregates parameters. These findings agree with those of Quintelas et al (2020), showing that a change in the biomass structure occurs when IBU is added at 1, 10, and 20 mg L − 1 . Fig.…”

“…IBU (in samples collected from the influent and effluent SBR) was assayed as previously described (Quintelas et al, 2020).…”

The effect of caffeine, metronidazole, and ibuprofen on continuous flow activated sludge process

“…Although it was reported by Jiménez‐Silva et al 33 . that ibuprofen affects the biomass of the activated sludge by reducing the biological oxygen uptake and decreasing the bound of extracellular polymeric substances, the reported removal rates of ibuprofen treated by activated sludge process or membrane bioreactor were in the range 90–100% 33–35 . In addition, common water treatment methods, like sand filtration, coagulation, or chlorination, are reported to not be very effective in ibuprofen removal 33 …”

Structural and metabolic profiling of Lycopersicon esculentum rhizosphere microbiota artificially exposed at commonly used Non-Steroidal Anti-Inflammatory Drugs

“…They reach soil system through reuse either of treated municipal wastewater in irrigation purposes (Mordechay et al, 2021;Grabicova et al, 2020;), or of the resulted sludge and biosolids as fertilizers (Mejias et al, 2021;Xu et al, 2009). Their common occurrence in soil environment raised high concern because of continuous input (Quintelas et al, 2020;Duan et al, 2013), subsequent accumulation potential (Mordechay et al, 2021;) and their potential ecotoxicological effects on nontargeted living organisms at different trophic levels (Mejias et al, 2021;Grabicova et al, 2020;Papaioannou et al, 2020;Cycon et al, 2016).…”