Considerable concern exists regarding the appearance and effects of trace and ultra trace pollutants in the aquatic environment. In this context, it is necessary to identify relevant hot spot wastewater - such as hospital wastewater - and to implement specific wastewater treatment solutions. Membrane bioreactor (MBR) technology seems to be a suitable pre-treatment approach for the subsequent advanced treatment by high pressure membrane systems such as nanofiltration (NF) and reverse osmosis (RO). This paper is based upon investigations on the first full scale MBR for separate treatment of hospital wastewater in Germany. In this study an NF as well as an RO module for further treatment of the MBR filtrate were tested. The removal efficiencies were assessed using the following target compounds: bezafibrate, bisoprolol, carbamazepine, clarithromycin, ciprofloxacin, diclofenac, ibuprofen, metronidazole, moxifloxacin, telmisartan and tramadol. In summary, the results of this study confirmed that MBR technology followed by an advanced treatment for trace pollutant removal is an adequate approach for specific treatment of hot spot wastewater such as hospital wastewater. In particular, it was shown that - comparing the tested NF and RO - only (a two stage) RO is appropriate to remove pharmaceutical residues from hospital wastewater entirely. The recommended yield of the 2-stage RO is 70% which results in a retentate sidestream of 9%. Our investigations proved that RO is a very efficient treatment approach for elimination of trace pollutants.

Membrane Bioreactors (MBR) are a very attractive option for the treatment of hospital wastewater and elimination of pharmaceuticals in high density urban areas. The present investigation showed that, depending on the substance, between 19% and 94% of the level of antibiotics found in the environment originate from hospitals. Because of their ecotoxic potential, hospital wastewaters can have a significant impact on the environment. The segregation of these wastewaters and their separate treatment at the source can reduce the entry of drugs in waterways and enable water reuse after adequate polishing treatment processes.

Membrane bioreactor (MBR) technology is a very reliable and extensively tested solution for biological wastewater treatment. Nowadays, separate treatment of highly polluted wastewater streams especially from hospitals and other health care facilities is currently under investigation worldwide. In this context, the MBR technology will play a decisive role because an effluent widely cleaned up from solids and nutrients is absolutely mandatory for a subsequent further elimination of organic trace pollutants. Taking hospital wastewater as an example, the aim of this study was to investigate to what extent MBR technology is an adequate 'pre-treatment' solution for further elimination of trace pollutants. Therefore, we investigated - within a 2-year period - the performance of a full-scale hospital wastewater treatment plant (WWTP) equipped with a MBR by referring to conventional chemical and microbiological standard parameters. Furthermore, we measured the energy consumption and tested different operating conditions. According to our findings the MBR treatment of the hospital wastewater was highly efficient in terms of the removal of solids and nutrients. Finally, we did not observe any major adverse effects on the operation and performance of the MBR system which potentially could derive from the composition of the hospital wastewater. In total, the present study proved that MBR technology is a very efficient and reliable treatment approach for the treatment of highly polluted wastewater from hospitals and can be recommended as a suitable pre-treatment solution for further trace pollutant removal.

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