Fate of Trace Organic Compounds in Granular Activated Carbon (GAC) Adsorbers for Drinking Water Treatment

Granular activated carbon (GAC) adsorbers for drinking water treatment were operated for approx. 14 months and the breakthrough of dissolved organic carbon (DOC) and trace organic chemicals (TOrCs) was monitored. Effluent concentration profiles of gabapentin and valsartan acid increase already at throughputs of <10,000 BV. The corresponding breakthrough curves flatten out without reaching the influent concentration level. This strongly indicates biological degradation of these substances in the GAC adsorbers under aerobic conditions, contributing to a more efficient use of GAC. The observed biodegradation in pilot GAC adsorbers also confirms recent reports of biodegradation of gabapentin and valsartan acid during managed aquifer recharge. Oxypurinol is comparatively well adsorbed and no breakthrough was observed during the experimental period. Adsorption capacity and breakthrough characteristics of oxypurinol appear very similar to carbamazepine. Breakthrough of GAC adsorbers operated with drinking water was compared to those of groundwater-fed adsorbers. The results show, that it is generally advisable to use previously aerated influents for GAC fixed-bed adsorbers because this can substantially improve biological removal of otherwise poorly adsorbable compounds and ensure full GAC accessibility for adsorbates by avoiding the undesirable formation of inorganic precipitates on adsorption sites.BMBF, 02WRS1368, TestTools – Entwicklung und Validierung von schnellen Testmethoden zum Spurenstoffverhalten in technischen und natürlichen Barrieren des urbanen Wasserkreislauf

Morphology of the canine omentum, part 2: the omental bursa and its compartments materialized and explored by a novel technique

The canine omental bursa is a virtual cavity enclosed by the greater and lesser omentum. While previous representations of this bursa were always purely schematic, a novel casting technique was developed to depict the three-dimensional organization of the omental bursa more consistently. A self-expanding polyurethane-based foam was injected into the omental bursa through the omental foramen in six dogs. After curing and the subsequent maceration of the surrounded tissues, the obtained three-dimensional casts could clearly and in a reproducible way reveal the omental vestibule, its caudal recess and the three compartments of the splenic recess. The cast proved to be an invaluable study tool to identify the landmarks that define the enveloping omentum. In addition, the polyurethane material can easily be discerned on computed tomographic images. When the casting technique is preceded by vascular injections, the blood vessels that supply the omentum can be outlined as well

Morphology of the canine omentum, part 1: arterial landmarks that define the omentum

Although the omentum remains an enigmatic organ, research during the last decades has revealed its fascinating functions including fat storage, fluid drainage, immune activity, angiogenesis and adhesion. While clinicians both in human and veterinary medicine are continuously exploring new potential omental applications, detailed anatomical data on the canine omentum are currently lacking, and information is often retrieved from human medicine. In this study, the topographic anatomy of the canine greater and lesser omentum is explored in depth. Current nomenclature is challenged, and a more detailed terminology is proposed. Consistent arteries that are contained within folds of the superficial omental wall are documented, described and named, as they can provide the anatomical landmarks that are necessary for unambiguous scientific communication on the canine omentum. In an included dissection video, the conclusions and in situ findings described in this study are demonstrated

Alternative elektronische Tierkennzeichnung

Das neue Tieridentifikationssystem Agro SAW IDENT wurde gemeinsam mit Industriepartnern entwickelt. Den Kern bilden piezoelektrische Kristalle mit aufgedampften Metallstrukturen, die den internationalen Tiercode darstellen. Zum Auslesen des Tiercodes werden akustische Oberflächenwellen (Surface Acoustic Wave = SAW) ohne jegliche Energiequelle genutzt. Die SAW-Codierung und der Charakter der Funkübertragung im Mikrowellenbereich um 2,4 GHz unterscheiden sich grundlegend von der üblichen Tieridentifikation im Niederfrequenzbereich bei 134 kHz. Die Vorteile der passiven SAW-Identifikation liegen in der höheren Lesereichweite bis zu 10 m und der sehr kurzen Identifikationsdauer unter 10 ms bei hoher Erkennungssicherheit. In vier Betrieben wurde an 1.652 Milchkühen die Funktionssicherheit untersucht

Anthropogenic organic micro-pollutants and pathogens in the urban water cycle: assessment, barriers and risk communication (ASKURIS)

In urban areas, water often flows along a partially closed water cycle in which treated municipal wastewater is discharged into surface waters which are one source of raw waters used for drinking water supply. A number of organic micro-pollutants (OMP) can be found in different water compartments. In the near future, climatic and demographic changes will probably contribute to an increase of OMP and antibiotic-resistant pathogens in aquatic ecosystems. The occurrence of OMP, possible adverse effects on aquatic organisms and human health and the public perception must be carefully assessed to properly manage and communicate potentially associated risks and to implement appropriate advanced treatment options at the optimum location within the water cycle. Therefore, the interdisciplinary research project ASKURIS focuses on identification and quantification, toxicological assessment and removal of organic micro-pollutants and antibiotic-resistant pathogens in the Berlin water cycle, life cycle-based economic and environmental assessment, public perception and management of potential risks

Einflüsse organischer Hintergrundverbindungen auf die Adsorption organischer Mikroverunreinigungen an Aktivkohle

Adsorption using powdered or granular activated carbon (PAC, GAC) is an advanced treatment for the removal of organic micro-pollutants (OMP) from waters like drinking waters (DW) or wastewater treatment plant (WWTP) effluents. Such waters contain background organic matter (BOM) which can adsorb at the same time as OMP. This competitive adsorption adversely affects OMP removals. The present study aims at advancing PAC and GAC laboratory tests for a more profound characterization of competitive adsorption in different waters, and its prediction using different mathematical and analytical tools. The high and low molecular weight BOM of WWTP effluent were separated using membrane techniques. Then, the respective impacts on OMP adsorption onto PAC were investigated. The low molecular weight (LMW) organics are the most competitive BOM fraction. In miniaturized GAC filters, the concept of rapid small-scale column tests (RSSCT) was used on WWTP effluent. Among the BOM fractions, the LMW organics have the strongest retention and thus adsorption affinity, underlining their competitiveness. Using ozonation prior to PAC, the aromaticity and hydrophobicity of BOM were shown to crucially impact OMP adsorption. The results imply synergies of ozonation prior to activated carbon treatment. The influence of the water origin on OMP-BOM adsorption competition was tested with PAC on five DW and seven WWTP effluents. High comparability was ensured by adjusting similar concentration ratios of OMP/BOM in all waters (BOM reflected by dissolved organic carbon — DOC). Within both groups of waters (DW or WWTP effluents), respectively, the relationships between the PAC loadings and the OMP liquid phase concentrations were similar (for a given OMP). Thus, BOM from different DW affects OMP adsorption similarly (the analogue applies to WWTP effluents). In the equivalent background compound (EBC) model, the EBC concentrations correlate with the DOC (DW/ WWTP effluents separately) and the LMW organics concentration (all waters together). OMP adsorption in waters ex-cluded from the correlations could be modelled satisfyingly with the DOC or the LMW organics concentration. In further tests with GAC treating DW and WWTP effluent, the breakthrough curves could be superimposed by using the LMW organics throughput. In addition, the GAC capacity is proportional to the respective OMP influent concentration. In a PAC performance test, the OMP removals from WWTP effluent by eight PAC correlated with the removals of the surrogate parameter UV254 absorption, mostly independent of the PAC. The UV254 removal also correlated with OMP removals in many other tests of this study. Additional tests were developed for lab-scale investigations of OMP adsorption in multi-stage PAC reuse. A single relationship between the PAC loadings and the liquid phase OMP concentrations appears valid for all stages. Based on this result, a simple modification of the EBC model was developed for assessing the efficiency of PAC reuse. This study shows the transferability of PAC and GAC adsorption data in different waters. The developed approaches alleviate practical estimations of OMP adsorption in various waters, by using comparatively simple experimental, analytical, and mathematical tools.Die Adsorption an Pulver- oder granulierte Aktivkohle (PAK, GAK) dient der Entfernung organischer Spurenstoffe aus Wässern wie Trinkwasser (TW) oder Kläranlagenablauf (KAA). Solche Wässer enthalten Hintergrundorganik, die zeitgleich mit den Spurenstoffen adsorbiert. Diese Adsorptionskonkurrenz verschlechtert die Spurenstoff-Entfernung. In der vorliegenden Studie wurden PAK- und GAK-Labormethoden weiterentwickelt, um die Adsorptionskonkurrenz in verschiedenen Wässern zu charakterisieren und mittels mathematischer und analytischer Tools vorherzusagen. Mittels Membrantechniken wurden höher- und niedermolekulare Hintergrundorganik getrennt. Anschließend wurde der jeweilige Einfluss auf die Spurenstoff-Adsorption an PAK in KAA untersucht. Die niedermolekulare Hintergrundorganik übt die stärkste Adsorptionskonkurrenz aus. In Miniatur-GAK-Filtern wurde das Konzept der rapid small-scale column tests (RSSCT) auf KAA angewendet. Rückhalt und somit Adsorptionsaffinität und Konkurrenzfähigkeit sind bei der niedermolekularen Hintergrundorganik am stärksten. Desweiteren wurde per Vor-Ozonung der Einfluss der Hintergrundorganik-Aromatizität und Hydrophobizität auf die Spurenstoff-Adsorption an PAK gezeigt. Es ergeben sich synergetische Effekte bei einer Ozonung vor Aktivkohleadsorption. Der Einfluss der Wasserherkunft auf die Adsorptionskonkurrenz zwischen Spurenstoffen und Hintergrundorganik wurde an fünf TW und sieben KAA mittels PAK getestet. Eine hohe Vergleichbarkeit wurde durch ähnliche Verhältnisse an Spurenstoff/ Hintergrundorganik gewährleistet (letztere verkörpert per gelösten organischen Kohlenstoff, DOC). Die Zusammenhänge zwischen PAK-Beladung und wässriger Spurenstoff-Konzentration waren in der jeweiligen Wassergruppe (TW, KAA) ähnlich (für den jeweiligen Spurenstoff). Folglich ist die Beeinträchtigung der Spurenstoff-Adsorption durch die Hintergrundorganik verschiedener TW ähnlich (analoges gilt für KAA). Im equivalent background compound (EBC) Modell korrelieren die modellierten EBC-Konzentrationen mit dem DOC (separate Korrelationen für TW und KAA) und mit der Konzentration der niedermolekularen Hintergrundorganik (alle Wässer gemeinsam). Die Spurenstoff-Adsorption in von den Korrelationen ausgeschlossenen Wässern konnte mittels DOC oder der Konzentration der niedermolekularen Hintergrundorganik modelliert werden. Ferner konnten die GAK-Durchbruchskurven von Spurenstoffen in TW und KAA per Auftragung über den Durchsatz an niedermolekularer Hintergrundorganik überlagert werden. Außerdem ist die GAK-Kapazität proportional zur jeweiligen Spurenstoff-Zulaufkonzentration. In einem Vergleich von acht PAK korrelieren die Spurenstoff-Entfernungen in KAA weitgehend unabhängig von der PAK mit der Entfernung des Surrogatparameters UV254-Absorption. Auch in anderen Versuchen dieser Studie korreliert die Spurenstoff-Entfernung mit der UV254-Entfernung. Desweiteren wurde ein Test für die Untersuchung der Spurenstoff-Adsorption bei mehrstufiger PAK-Wiederverwendung entwickelt. Zwischen der PAK-Beladung und der wässrigen Spurenstoff-Konzentration besteht in allen Stufen der gleiche Zusammenhang. Das EBC Modell wurde modifiziert, um die Effizienz bei der PAK-Wiederverwendung abzuschätzen. Diese Studie zeigt die Übertragbarkeit der Spurenstoff-Adsorption an PAK und GAK in verschiedenen Wässern. Die entwickelten Methoden ermöglichen praktische Vorhersagen der Spurenstoff-Adsorption mittels einfacher experimenteller, analytischer und mathematischer Tools.BMBF, 02WRS1278, RiSKWa - Verbundprojekt ASKURIS: Anthropogene Spurenstoffe und Krankheitserreger im urbanen Wasserkreislauf: Bewertung, Barrieren und Risikokommunikatio