Laurence Palmowski

Full scale membrane bioreactor treatment of hospital wastewater as forerunner for hot-spot wastewater treatment solutions in high density urban areas

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.

Energy demand for elimination of organic micropollutants in municipal wastewater treatment plants

Organic micropollutants (OMP), e.g. pharmaceuticals and household/industrial chemicals, are not fully eliminated in state-of-the-art municipal wastewater treatment plants and can potentially harm the aquatic environment. Therefore, several pilot and large-scale investigations on the elimination of organic micropollutants have taken place in recent years. Based on the present findings, the most efficient treatment steps to eliminate organic micropollutants have proven to be ozonation, adsorption on powdered activated carbon (PAC), or filtration through granular activated carbon (GAC). Yet a further treatment step implies an increase in energy demand of the wastewater treatment plant, which has to be considered along with OMP elimination. To this aim, data on energy demand of ten large-scale municipal wastewater treatment plants (WWTP) with processes for OMP elimination was collected and analyzed. Moreover, calculations on energy demand beyond the WWTP for production and transport of ancillary materials were performed to assess the cumulative energy demand of the processes. An assessment of the greenhouse gas emissions of the processes was achieved, which shall facilitate future life cycle analyses. The results show that energy demand of ozonation at the wastewater treatment plant is dependent upon the ozone dosage and is significantly higher than energy demand of PAC addition or GAC filtration (2 to 4 times higher without consideration of delivery heads). Despite uncertainties regarding the energy demand for production of activated carbon, it could be shown that the cumulative energy demand of adsorption steps is significantly higher than the energy demand at the WWTP. Using reactivated GAC can lead to energy and greenhouse gas emissions savings compared to using fresh GAC/PAC. Moreover, energy demand is always plant-specific and depends on different factors (delivery heads, existing filtration or post-treatment etc.). Since processes for elimination of organic micropollutants are still in a developing phase, future optimization steps shall minimize their energy demand.

Risikokommunikation zu Arzneimitteln in Gewässern: Ein Balanceakt

ZusammenfassungHintergrundArzneimittelnutzer können zur Minderung des Arzneimitteleintrags in die Gewässer beitragen. Zweck der Literaturstudie war Erkenntnisgewinn darüber, wie Risikokommunikation, die dazu motivieren will, inhaltlich gestaltet werden sollte. Fokussiert wurde auf die Risikowahrnehmungsforschung, aus der Rückschlüsse auf die intuitive Wahrnehmung des Risikos „Arzneimittel in Gewässern“ gezogen wurden.ErgebnisseDie Risikoquelle Arzneimittel in Gewässern besitzt Merkmale, die Menschen dazu bewegen, ein Risiko als vernachlässigbar einzustufen, als auch Merkmale, die die Einschätzung als hohes Risiko befördern. Letztere sind zentrale Bestandteile des Risikotypus „Risiko als Frühindikator für schleichende Gefahren“. Bei den Adressaten muss mit geringem Wissen und niedriger Motivation zur intensiveren Informationsverarbeitung gerechnet werden.SchlussfolgerungRisikokommunikation zu Arzneimitteln in Gewässern ist ein Balanceakt zwischen Aktivieren und Beruhigen. „Vorsorge lohnt sich“ sollte die Grundbotschaft sein. Schlüsselreize sind von besonderer Bedeutung, bei emotionalen Reizen in Bezug auf Trinkwasser ist Vorsicht geraten. Der breitere Bezugsrahmen „Verantwortungsvoller Umgang mit Arzneimitteln“ könnte als Aufmerksamkeitsreiz dienen.AbstractBackgroundPharmaceutical users can contribute to reducing the input of pharmaceuticals into the water cycle. The purpose of the literature study was to gain insight on how risk communication should be designed in terms of content to motivate to make this contribution. Focus was on risk perception research from which conclusions were drawn about intuitive risk perception around pharmaceuticals in the water cycle.ResultsThe risk source “pharmaceuticals in the water cycle” has attributes that induce people to perceive a risk as negligible as well as attributes which promote the perception that a risk is high. The latter are main elements of the risk pattern “risk as an early indication of insidious danger”. It is likely that part of the addressees have little knowledge and low motivation to deal more intensively with the offered information.ConclusionRisk communication on pharmaceuticals in the water cycle requires balancing between awakening and reassuring. “It’s worth taking precautionary measures” should be the main message. Heuristic cues are of particular importance, special attention is required with respect to emotional cues in relation to drinking water. The broader frame of “Dealing responsibly with pharmaceuticals” could serve as an attention cue.

Carbon recovery from screenings for energy-efficient wastewater treatment

The energy content of screenings from six municipal wastewater treatment plants (WWTPs) was examined. Hourly samples of separated screenings were taken over 24 hours at three of the plants to illustrate diurnal variations. To recover the chemical energy, which usually leaves the WWTP with the screenings, a screenings wash press was used to transfer organic matter from the solid into the liquid phase. The chemical energy of raw and compacted washed screenings as well as the chemical energy of washing water were determined by measuring the chemical oxygen demand (COD) for the six WWTPs. A mass weighted average of 1.35 gCOD/gdm (dm: dry matter) was found in the raw screenings of three WWTPs. The overall recovered energy from screenings was found to range from 0.27 to 0.62 gCOD/gdm. This washed-out COD found in the washing water could be sent for anaerobic digestion or to the wastewater treatment process as a carbon source for denitrification.