Person: Ruhl, Aki Sebastian
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Aki Sebastian
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Veröffentlichung Automated scraping and analyses of drinking water quality data(2023) Ruhl, Aki Sebastian; Saal, LeonDrinking water quality data, though regularly monitored, is not available in Germany as national overview, but only decentralized from the water suppliers. On the national level, only the number of limit exceedances are reported. An overview on drinking water qualities as complete as possible however is necessary to assess and develop regulations and helpful for authorities, political decision makers, the public and the scientific community. Due to the fragmented nature of the data sources, web-scraping was used in the present study to mitigate aforementioned challenges and knowledge gaps. Data from 502 water supply areas were compiled and further evaluated. The extent and form of reported values varied strongly, as did the availability of data for the different water supply areas. The results show, that the scraped values were not close to but well below associated legal limits or guidance values. For organic parameters, the reported values were mostly below the respective limits of quantification. However, further developments are needed to cover more water supply areas in Germany and internationally. © 2023 The AuthorsVeröffentlichung Characterization of activated carbons for water treatment using TGA-FTIR for analysis of oxygen-containing functional groups(2022) Dittmann, Daniel; Zietzschmann, Frederik; Ruhl, Aki Sebastian; Schumann, Pia; Saal, Leon; Braun, UlrikeWater treatment with activated carbon (AC) is an established method for the removal of organic micropollutants and natural organic matter. However, it is not yet possible to predict the removal of individual pollutants. An appropriate material characterization, matching adsorption processes in water, might be the missing piece in the puzzle. To this end, this study examined 25 different commercially available ACs to evaluate their material properties. Frequently reported analyses, including N2 adsorption/desorption, CHNS(O), point of zero charge (PZC) analysis, and X-ray photoelectron spectroscopy (XPS) were conducted on a selected subset of powdered ACs. Inorganic elements examined using X-ray fluorescence (XRF) and X-ray iffraction spectroscopy (XRD) revealed that relative elemental contents were distinctive to the individual AC's raw material and activation procedure. This study also is the first to use thermogravimetric analysis (TGA) coupled to Fourier-transform infrared spectroscopy (FTIR) to conduct quantitative analyses of functional surface oxygen groups (SOGs: carboxylic acid, anhydride, lactone, phenol, carbonyl, and pyrone groups) on such a large number of ACs. The comparably economical TGA provides a surrogate for the PZC, the oxygen and carbon content, as well as mass loss profiles that depict the AC's chemistry. Furthermore, we found that SOG contents determined by TGA-FTIR covered a wide individual range and depended on the raw material of the AC. Surface chemistry might therefore provide an indication of the suitability of a particular AC for a variety of target substances in different target waters. TGA and TGA-FTIR can help practitioners to control AC use in waterworks or wastewater treatment plants.Veröffentlichung Persistente mobile organische Chemikalien in der aquatischen Umwelt: Quellen, Vorkommen und technische Möglichkeiten zu ihrer Entfernung in der Trinkwasseraufbereitung (PROTECT)(2023) Muschket, Matthias; Kuckelkorn, Jochen; Zahn, Daniel; Neuwald, Isabelle; Schumann, Pia; Rabe, Luisa; Ruhl, Aki Sebastian; Helmholtz-Zentrum für UmweltforschungVeröffentlichung Changes in dissolved organic matter and oxygen consumption in different bank filtration simulations at different scales(2023) Klitzke, Sondra; Ruhl, Aki Sebastian; Zeeshan, MuhammadBoth concentrations and compositions of dissolved organic matter (DOM) and the availability of oxygen affect transformation processes in close-to-nature drinking water treatments such as bank filtration and artificial groundwater infiltration. This study focused on quantitative and qualitative analyses of DOM in different saturated sand column systems of different dimensions, histories and operating conditions using fluorescence spectroscopy. The study revealed the presence of two fluorescent DOM (fDOM) fractions (humic-like compounds) through parallel factor analysis (PARAFAC). DOM, fDOM and specific UV absorbance (SUVA) at 254 nm were reduced and correlated in indoor systems. In outdoor columns, the removals of DOM and fDOM were comparably high, but the increased SUVA indicated an increase in aromaticity. Dissolved oxygen consumption corresponded to organic content in sand, independent of residence times. Overall, bank filtration is an effective option to remove biodegradable DOM under outdoor natural conditions. © Royal Society of Chemistry 2023Veröffentlichung Indications of recent warm and dry summers' impact on private wells for drinking-water supply in Germany: a review of press articles(2022) Görnt, Annika; Rickert, Bettina; Vogelsang, L.; Ruhl, Aki SebastianClimatic changes lead to seasonal droughts with declining groundwater levels, and - especially in rural regions - private wells in the upper aquifer might fall dry. However, only limited information and no systematic administrative reporting of the extent are available for Germany yet. Therefore, a systematic analysis of newspaper articles as a promising source of information was conducted for the extraordinarily hot summers of 2018, 2019 and 2020. The results of the database searches were analysed with respect to frequency and local and regional hotspots, relations to climatic data, extent of the reported dry-fallings and emergency water supply. The analysis indicates hotspots particularly for the federal states of Saxony, where a subsidy programme for connecting to the public water supply was reissued in 2019, for Bavaria and North Rhine-Westphalia. Emergency supply was realised through various approaches. It was partly required until the winter months and did not always have drinking-water quality. As private wells are particularly vulnerable to the effects of climate change, their operators should be involved as a stakeholder group in future discussions about allocating water resources to increasingly competing uses in periods of scarcity. © 2022 The AuthorsVeröffentlichung Polystyrene Microplastics modulate the toxicity of the hydrophilic insecticide Thiacloprid for Chironomid Larvae and also influence their burrowing behavior(2022) Krais, Stefanie; Anthes, Nils; Huppertsberg, Sven; Ruhl, Aki SebastianAs there is still little knowledge of interactions between microplastics (MP) and hydrophilic compounds, we propose ways the toxicity of hydrophilic pesticides can be modulated by MP, when sorption can be excluded. Larvae of Chironomus riparius were exposed to thiacloprid (TH, 1 mikrog/L) and polystyrene microplastic particles (PS; <50 mikrom; 150,000 and 1,000,000 particles/L) for 96 h, solely or in co-exposure. Burrowing behavior and mortality were observed. Larvae in treatments containing PS established themselves quicker in the sediment and kept the ability to rebury for a longer time compared to control and TH, respectively. While TH elevated the mortality, exposure to PS alone did not affect the survival of the larvae. In co-exposure of TH and PS, a concentration of 150,000 particles/L significantly reduced the toxicity of 1 mikrog/L TH after 96 h, an effect that was not observed at 1,000,000 particles/L. Therefore, we hypothesize that this modulation of the toxicity of TH eventually may have resulted from a combination of a "protective MP layer" in the gut and a higher retention time of particles in larvae exposed to 150,000 particles/L than in those exposed to 1,000,000 particles/L due to the lower number of ingestible particles in the former. © 2022 by the authorsVeröffentlichung Pilot-scale vanadium adsorption onto in-situ biogenic amorphous ferric hydroxide(2023) Mahringer, Daniel; Ruhl, Aki Sebastian; Zerelli, Sami SofieneIn order to reach 4 (micro)g l-1 vanadium in drinking water adsorption onto in-situ biogenic amorphous ferric hydroxide (AFH) is identified as robust new treatment. The evaluation of its technical feasibility and robustness was the aim of this study. As approach at pilot-scale, Fe(II) and oxygen was dosed before pilot waterworks and Fe(II) subsequently biotically oxidized and precipitated in a filter bed. The so in-situ generated biogenic AFH served as adsorbent for vanadium removal. Results show that an initial vanadium concentration of 30 (micro)g l-1 was removed to below 4 (micro)g l-1, if at least 3 mg l-1 Fe(II) were dosed, resulting in a loading of 8.7 mg V per g AFH. A vanadium concentration of 60 (micro)g l-1 with a dosage of 3 mg l-1 Fe(II) was the upper limit for sufficient removal. Vanadium removal increased with increasing pH in the technical setup, due to faster oxidation of Fe(II) in the supernatant, even though adsorption capacity of AFH decreases with increasing pH. A filtration velocity of 20 m h -1 represented the highest velocity to undercut 4 (micro)g l-1 vanadium in the effluent. By mixing Fe(II) containing groundwater with oxygen and vanadium containing water prior to an adsorption filter with AFH sufficient removal was reached, however dependent on the resulting Fe(II) concentration. © 2023 by the authorsVeröffentlichung Persistente und mobile Stoffe im Wasserkreislauf(2023) Muschket, Matthias; Kuckelkorn, Jochen; Zahn, Daniel; Neuwald, Isabelle; Schumann, Pia; Rabe, Luisa; Ruhl, Aki SebastianVeröffentlichung Perfluoroalkyl substances (PFAS) adsorption in drinking water by granular activated carbon: Influence of activated carbon and PFAS characteristics(2021) Cantoni, Beatrice; Turolla, Andrea; Ruhl, Aki Sebastian; Wellmitz, JörgPerfluoroalkyl substances (PFAS) persistence in the environment leads to their presence in drinking water, that is of high concern due to their potential human health risk. Adsorption onto activated carbon (AC) has been identified as an effective technique to remove PFAS. Adsorption isotherms and breakthrough curves, determined by rapid small-scale column tests (RSSCTs), were studied for eight PFAS and four granular ACs, characterized by different origins, porosities and numbers of reactivation cycles. Both batch and RSSCT results highlighted the strong interaction of AC and PFAS characteristics in adsorption capacity. The most important factor affecting AC performance is the surface charge: a positively-charged AC showed higher adsorption capacities with greater Freundlich constants (KF) and later 50% breakthroughs compared to the AC with neutral surface. Among the positively-charged ACs, a microporous AC demonstrated higher adsorption capacities for hydrophilic and marginally hydrophobic PFAS, while the mesoporous AC performed better for more hydrophobic PFAS, possibly due to lower pore blockage by organic matter. These results were confirmed at full-scale through a one-year monitoring campaign, in which samples were collected at the inlets and outlets of GAC systems in 17 drinking water treatment plants spread in a wide urban area, where the four analyzed ACs are used. © 2021 Elsevier B.V.Veröffentlichung Impacts of autochthonous particulate organic matter on redox-conditions and elimination of trace organic chemicals in managed aquifer recharge(2023) Filter, Josefine; Ermisch, Till; Jekel, Martin; Ruhl, Aki SebastianAutochthonous carbon fxation by algae and subsequent deposition of particulate organic matter can have signifcant efects on redox conditions and elimination of trace organic chemicals (TOrCs) in managed aquifer recharge (MAR). This study investigated the impacts of diferent algae loadings (0-160 g/m2) and infltration rates (0.06-0.37 m/d) on overall oxygen consumption and elimination of selected TOrCs (diclofenac, formylaminoantipyrine, gabapentin, and sulfamethoxazole) in adapted laboratory sand columns. An infltration rate of 0.37 m/d in conjunction with an algae load of 80 g/m2 (dry weight) sustained oxic conditions in the sand bed and did not afect the degradation of TOrCs. Thus, the availability of easily degradable organic carbon from algae did not infuence the removal of TOrCs at an infuent concentration of 1 Ìg/L. In contrast, a lower infltration rate of 0.20 m/d in combination with a higher algae loading of 160 g/m2 caused anoxic conditions for 30 days and signifcantly impeded the degradation of formylaminoantipyrine, gabapentin, sulfamethoxazole, and diclofenac. Especially the elimination of gabapentin did not fully recover within 130 days after pulsed algae deposition. Hence, measures like micro-sieving or nutrient control are required at bank fltration or soil aquifer treatment sites with low infltration rates. © The Author(s) 2023