Removal of pharmaceuticals by abiotic and biotic adsorption processes and bioregeneration

In this study, adsorption, desorption and bioregeneration of paracetamol (PAR) and carbamazepine (CBZ) with powder activated carbon (TAK) were investigated. Parallel to bioregeneration studies, biodegradation studies of pharmaceuticals for control reactor have been carried out. In the adsorption experiments carried out in the abiotic environment, wood-based powdered activated carbon was used as the adsorbent and the adsorption of both materials with appropriate contact time and appropriate PAC dose was realized with high efficiency (>99%). Desorption experiments carried out in the abiotic medium at 25oC, and with high desorption efficiency were not obtained for both substances. The cumulative desorption efficiency of PAR (26.3%) was higher than that of CBZ (5.4%), depending on the physicochemical properties of the substance. This result shows that the reversibility of the substance is also dependent on the nature of the adsorbate, besides its adsorbing property. In the bioregeneration study, the bioregenerability of powdered active carbon pre-loaded with pharmaceuticals was investigated at three different sludge ages. According to the results obtained from bioregeneration experiment which carried out with activated sludge taken from hospital wastewater membrane bioreactor (MBR) system, the bioregeneration efficiency of PAR at SRT 10 days was found to be 17.3%, bioregeneration efficiency at SRT 30 days was found to be 26.3%, and bioregeneration efficiency at SRT 60 days was found to be 20.1%. For CBZ, the bioregeneration efficiency at SRT 10 days was found to be 11.5%, biyoregeneration efficiency at SRT 30 days was found to be 29.3%, and biyoregeneration efficiency at SRT 60 days was found to be 26.2%. These results show that sludge age of 30 days is the optimum sludge age for bioregeneration. Since the desorption efficiency of CBZ is very low, CBZ bioregeneration has been achieved mainly by extracellular enzymes. The bioregeneration of PAR has been effected by both desorbability and extracellular enzymes. The results showed that bioregenerations of non-reversible compounds were also possible via active extracellular enzymes. For this reason, sludge age is predicted to be a very important factor for the activity of extracellular enzymes. In biodegradation studies carried out in both aerobic and anaerobic/anoxic conditions, PAR is able to biodegraded of high efficiency (> 98%) in both conditions. CBZ does not biodegraded in the anaerobic/anoxic conditions. In aerobic conditions it can be biologically degraded up to 30-40%. These results show that PAR can be easily biodegraded in all conditions where microorganisms are alive. The degradability of the resistant substance of CBZ depends on the operating conditions and the characterization of the sludge.