Pharmaceutical removal: synergy between biological and chemical processes for wastewater treatment

The occurrence of pharmaceuticals in the environment has become a worldwide environmental concern. After administration and excretion, pharmaceuticals end up in wastewater treatment plants. These plants, typically employing biological treatment, are not designed for their removal. Hence, numerous pharmaceuticals are emitted into the environment. Chemical treatment processes like ozonation can effectively remove pharmaceuticals, however these costly processes have disadvantages such as high energy consumption and by-product formation. On the contrary, biological treatment processes are less effective for pharmaceutical removal, but can complement chemical process by for instance by-product removal. In this dissertation the combination of biological and chemical treatment processes for pharmaceutical removal was therefore studied. We found complementariness between various combinations of biological and chemical processes, resulting in the design of cost-effective combined treatment processes for enhanced pharmaceutical removal from wastewater treatment plant effluents.</p

Sorption and biodegradation of six pharmaceutically active compounds under four different redox conditions

This study explored the removal of six pharmaceutically active compounds (PhACs) in lab-scale experiments with sediments under four redox conditions, namely aerobic, nitrate reducing, sulfate reducing, and methanogenic conditions using batch and column set-ups. Redox conditions were found to influence PhAC removal by sorption and biodegradation. The most optimal PhAC removal was observed at the outer ranges of the redox spectrum, i.e. either aerobic or deep anaerobic (sulfate reducing and methanogenic conditions), whereas nitrate reducing conditions were found least effective for PhACs biodegradation and sorption. For instance, sorption coefficient Kd values for metoprolol in column experiments were 90, 65, 42 and 11 L/kg for sulfate reducing, methanogenic, aerobic and nitrate reducing conditions, respectively. For the same conditions Kd values for propranolol were 101, 94, 55 and 55 L/kg, respectively. As expected, biodegradation efficiencies were highest under aerobic conditions, showing >99% removal of caffeine and naproxen, but no removal for propranolol and carbamazepine. The adaptive capacity of sediment was demonstrated by pre-exposure to PhACs leading to improved PhAC biodegradation. The results of this study indicate the necessity to combine diverse redox conditions, including aerobic conditions, for maximizing PhAC removal by sorption and biodegradation. Furthermore, our findings stress the need for additional treatment measures as recalcitrant PhACs are not effectively removed under any redox condition

Data underlying the publication: Optimizing biological effluent organic matter removal for subsequent micropollutant removal

Data underlying the publication: Optimizing biological effluent organic matter removal for subsequent micropollutant removal. In this dataset, the raw data on which the figures in the abovementioned publications are based can be found. Detailed description of the related data can be found in the readme

Removal of micropollutants from water and installation for use therein

The invention pertains to a process for the removal of micropollutants and/or other pollutants from water, comprising subjecting the water to a consecutive combination of biological adsorbent filtration (BAF) followed by oxidation treatment (OT), preferably ozone treatment. In a preferred embodiment, an adjustable amount of the OT effluent, preferably an adjustable amount ranging between 10- 100%, more preferably 20 - 90%, more preferably 20 - 80%, most preferably 20 - 50% of the OT effluent, is recirculated to the BAF. The process may involve monitoring the formation of oxidation products at the end of the OT, and/or for measuring TOC, DOC, SUVA, ammonium and/or specifically targeted pollutants in or at the end of the BAF, and controlling the amount of BAF-OT treated water which is recirculated to the consecutive steps of BAF and OT based on the output of the monitoring step

Enhanced pharmaceutical removal from water in a three step bio-ozone-bio process

Individual treatment processes like biological treatment or ozonation have their limitations for the removal of pharmaceuticals from secondary clarified effluents with high organic matter concentrations (i.e. 17 mg TOC/L). These limitations can be overcome by combining these two processes for a cost-effective pharmaceutical removal. A three-step biological-ozone-biological (BO3B) treatment process was therefore designed for the enhanced pharmaceutical removal from wastewater effluent. The first biological step removed 38% of ozone scavenging TOC, thus proportionally reducing the absolute ozone input for the subsequent ozonation. Complementariness between biological and ozone treatment, i.e. targeting different pharmaceuticals, resulted in cost-effective pharmaceutical removal by the overall BO3B process. At a low ozone dose of 0.2 g O3/g TOC and an HRT of 1.46 h in the biological reactors, the removal of 8 out of 9 pharmaceuticals exceeded 85%, except for metoprolol (60%). Testing various ozone doses and HRTs revealed that pharmaceuticals were ineffectively removed at 0.1 g O3/g TOC and an HRT of 0.3 h. At HRTs of 0.47 and 1.46 h easily and moderately biodegradable pharmaceuticals such as caffeine, gemfibrozil, ibuprofen, naproxen and sulfamethoxazole were over 95% removed by biological treatment. The biorecalcitrant carbamazepine was completely ozonated at a dose of 0.4 g O3/g TOC. Ozonation products are likely biodegraded in the last biological reactor as a 17% TOC removal was found. No appreciable acute toxicity towards D. magna, P. subcapitata and V. fischeri was found after exposure to the influents and effluents of the individual BO3B reactors. The BO3B process is estimated to increase the yearly wastewater treatment tariff per population equivalent in the Netherlands by less than 10%. Overall, the BO3B process is a cost-effective treatment process for the removal of pharmaceuticals from secondary clarified effluents

Improved biodegradation of pharmaceuticals after mild photocatalytic pretreatment

The combination of photocatalysis and biodegradation was investigated for the removal of nine selected pharmaceuticals as a means to reduce loadings into the environment. The combined process, consisting of a resource-efficient mild photocatalysis and a subsequent biological treatment, was compared to single processes of intensive photocatalysis and biological treatment. The UV-TiO2 based photocatalysis effectively removed atorvastatin, atenolol and fluoxetine (>80%). Biological treatment after mild photocatalytic pretreatment removed diclofenac effectively (>99%), while it persisted during the single biological treatment (<50%). Moreover, the biodegradation of atorvastatin, caffeine, gemfibrozil and ibuprofen was enhanced after mild photocatalytic pretreatment compared to biological treatment alone. The enhanced biodegradation of these pharmaceuticals appeared to be triggered by the biodegradation of photocatalytic products. Mild photocatalysis followed by biological treatment is an effective and resource-efficient combination for pharmaceutical removal that could substantially reduce the loading of pharmaceuticals into the environment.</p

Data underlying the publication: The effect of organic matter fractions on micropollutant ozonation in wastewater effluents

Data underlying the publication: Optimizing micropollutant removal by ozonation; interference of effluent organic matter fractions. In this dataset, the raw data on which the figures in the abovementioned publication are based can be found. Detailed description of the related data can be found in the README.</p

Data underlying the publication: The effect of organic matter fractions on micropollutant ozonation in wastewater effluents

Data underlying the publication: Optimizing micropollutant removal by ozonation; interference of effluent organic matter fractions. In this dataset, the raw data on which the figures in the abovementioned publication are based can be found. Detailed description of the related data can be found in the README.</p