A low‐cost environmental chamber to simulate warm climatic conditions

Environmental chambers are used for a variety of experiments in multiple disciplines but are often prohibitively expensive. In this study, we developed an environmental chamber that allows reliable regulation of temperature and relative humidity in a range typical for warm climatic conditions. As we have only used consumer products, which are readily available off the shelf, the device is affordable (<€900) and easy to replicate. The presented chamber has inner dimensions of 1,790 × 970 × 520 mm (height × width × depth). It is heated with two infrared lamps, and for moistening, an ultrasonic mister is used. Air dehumidification and cooling down to ambient temperature are realized with inflowing compressed laboratory air. Additionally, we installed a Peltier element cooling system to enable temperatures below the ambient laboratory temperature. The chamber works in a temperature and humidity range of 15–50 °C and 10–95%, respectively

Chlorine isotope fractionation during catalytic reductive dechlorination of Trichloromethane (CHCl₃) over palladium-on-alumina in hydrogen-saturated water: implication to managed aquifer recharge as sustainable storage solution for desalinated water (MAR-DSW) in Menashe recharge basin, Israel

During the storage of excess desalinated water in a managed coastal aquifer in Israel, chlorine in desalinated water may react with natural organic matter, forming toxic disinfection by-products (DBPs), like trihalomethanes (THMs). In order to facilitate managed aquifer recharge as storage solution for desalinated water (MAR-DSW), it is important to understand the mechanisms of the formation and degradation of such DBPs. In this work, degradation of chloroform (CHCl₃), a main pollutant of interest at the Menashe recharge basin in Israel, was investigated to derive chlorine isotope enrichment factors for the educt and degradation products as a part of the Israel-German joint research “aquifer recharge as sustainable storage solution for desalinated water (MAR-DSW)”. 100ml of deionized water spiked with 30mg/l chloroform was saturated with hydrogen, which serves as an electron donor. Then, 0.25g/l palladium was added as palladium-on-alumina (10% wt.) to catalyze the reaction. Samples were taken at specified intervals from a sampling port designed at the bottom of the reactor, which is closed with a plunger from the top so that no headspace was created as samples were taken out or during the entire experimental period. During degradation of chloroform, the change in chlorine isotope ratios of CHCl₃ as well as its chlorinated degradation products was determined using a gas-chromatograph-mass spectrometer online connected to a purge and trap system (P&T-GC/MS). This simple online method was developed and optimized at TU Darmstadt. In addition to the reaction kinetics, isotope fractionation of CHCl₃ and its degradation products dichloromethane (CH₂Cl₂) as well as methyl chloride (CH₃Cl) were investigated. A chlorine isotope enrichment factor (ε) of -2.7‰ was derived for chloroform using the Rayleigh equation. The investigation of isotope fractionation during the reductive dechlorination of chloroform i.e the Cl-CSIA can potentially be used as a tool to discriminate the source, pathway and fate of these compounds so as to foresee the feasibility of medium and long term use of managed aquifer recharge as a storage solution

Climate change or irrigated agriculture – what drives the water level decline of Lake Urmia

Lake Urmia is one of the largest hypersaline lakes on earth with a unique biodiversity. Over the past two decades the lake water level declined dramatically, threatening the functionality of the lake’s ecosystems. There is a controversial debate about the reasons for this decline, with either mismanagement of the water resources, or climatic changes assumed to be the main cause. In this study we quantified the water budget components of Lake Urmia and analyzed their temporal evolution and interplay over the last five decades. With this we can show that variations of Lake Urmia’s water level during the analyzed period were mainly triggered by climatic changes. However, under the current climatic conditions agricultural water extraction volumes are significant compared to the remaining surface water inflow volumes. Changes in agricultural water withdrawal would have a significant impact on the lake volume and could either stabilize the lake, or lead to its complete collapse

GeoLaB – Geothermal Laboratory in the crystalline Basement: synergies with research for a nuclear waste repository

Crystalline rocks are being considered as potential host rocks in the ongoing search for a suitable site for a nuclear waste repository in Germany, where there is no existing experience in terms of excavating a repository in crystalline rocks. The planned underground laboratory GeoLaB addressing crystalline geothermal reservoirs offers unique opportunities for synergies with nuclear waste disposal research and development, especially in the exploration and building phases

Optimization of compound‐specific chlorine stable isotope analysis of chloroform using the Taguchi design of experiments

Rationale Chloroform, a probable human carcinogen, is commonly detected in various concentration levels in many surface water and groundwater sources. Compound-specific chlorine stable isotope analysis (Cl-CSIA) is significant in investigating the fate of chlorinated contaminants in the environment. Analytical conditions should, however, be thoroughly examined for any isotopic fractionation. In this study, we simultaneously optimize three analytical parameters for a robust online Cl-CSIA of chloroform using the Taguchi design of experiments. Methods For Cl-CSIA, a purge-and-trap autosampler coupled to a gas chromatograph in tandem with a quadrupole mass spectrometer, with electron ionization in selected ion monitoring (SIM) mode, was used. Using the Taguchi method, the dominant parameter affecting the results of Cl-CSIA for chloroform was identified through concurrent investigation of the signal-to-noise ratios (S/N) of three parameters, each at three levels: purging time (5, 10, 15 min), transfer time (80, 120, 160 s), and dwell time (20, 60, 100 ms). Moreover, the optimum combination of the levels was identified. Results The purging time, with a maximum S/N, resulted in the highest influence on the isotope ratios determined. It was further refined through additional experiments to sufficiently extract chloroform from the aqueous phase. Accordingly, 8 min of purging time, 120 s transfer time and 100 ms dwell time were the optimum conditions for Cl-CSIA of chloroform. Post-optimization, a precision of ±0.28 ‰ was achieved for 8.4 nmol of chloroform (equivalent to 0.89 μg or approx. 25 nmol Cl-mass on column). Conclusions A simple online method for Cl-CSIA of chloroform was optimized with the Taguchi design of experiments. The Taguchi method was very useful for the optimization of the analytical conditions. However, the purging conditions should be fine-tuned and selected so that sufficient extraction of a target compound is confirmed to acquire a stable and higher precision of the method

A risk assessment methodology to evaluate the risk failure of managed aquifer recharge in the Mediterranean Basin

Managed aquifer recharge (MAR) can be affected by many risks. Those risks are related to different technical and non-technical aspects of recharge, like water availability, water quality, legislation, social issues, etc. Many other works have acknowledged risks of this nature theoretically; however, their quantification and definition has not been developed. In this study, the risk definition and quantification has been performed by means of &quot;fault trees&quot; and probabilistic risk assessment (PRA). We defined a fault tree with 65 basic events applicable to the operation phase. After that, we have applied this methodology to six different managed aquifer recharge sites located in the Mediterranean Basin (Portugal, Spain, Italy, Malta, and Israel). The probabilities of the basic events were defined by expert criteria, based on the knowledge of the different managers of the facilities. From that, we conclude that in all sites, the perception of the expert criteria of the non-technical aspects were as much or even more important than the technical aspects. Regarding the risk results, we observe that the total risk in three of the six sites was equal to or above 0.90. That would mean that the MAR facilities have a risk of failure equal to or higher than 90&iquest;% in the period of 2&ndash;6 years. The other three sites presented lower risks (75, 29, and 18&iquest;% for Malta, Menashe, and Serchio, respectively). Managed aquifer recharge (MAR) can be affected by many risks. Those risks are related to different technical and non-technical aspects of recharge, like water availability, water quality, legislation, social issues, etc. Many other works have acknowledged risks of this nature theoretically; however, their quantification and definition has not been developed. In this study, the risk definition and quantification has been performed by means of &quot;fault trees&quot; and probabilistic risk assessment (PRA). We defined a fault tree with 65 basic events applicable to the operation phase. After that, we have applied this methodology to six different managed aquifer recharge sites located in the Mediterranean Basin (Portugal, Spain, Italy, Malta, and Israel). The probabilities of the basic events were defined by expert criteria, based on the knowledge of the different managers of the facilities. From that, we conclude that in all sites, the perception of the expert criteria of the non-technical aspects were as much or even more important than the technical aspects. Regarding the risk results, we observe that the total risk in three of the six sites was equal to or above 0.90. That would mean that the MAR facilities have a risk of failure equal to or higher than 90 % in the period of 2&ndash;6 years. The other three sites presented lower risks (75, 29, and 18 % for Malta, Menashe, and Serchio, respectively)

Low Trihalomethane Formation during Managed Aquifer Recharge with Chlorinated Desalinated Water

Trihalomethanes (THMs) are toxic disinfection by-products, formed in the reaction of chlorine with organic matter. This work aimed to study THM formation during a unique case study of managed aquifer recharge (MAR) with chlorinated desalinated seawater. THM formation was tested in the field, along a 3.0 m deep vadose zone gallery. Two small-scale experiments were conducted in the site, with untreated and with bromide spiked desalinated seawater. These were accompanied by a large-scale, ~1-month long operational MAR event. In the small-scale experiments, THM concentrations were shown to increase with bromide concentrations, with increasing dominance of the brominated species. Nevertheless, concentrations remained within the single µg/L range, which is an order of magnitude lower than drinking water regulations. Such low THM concentrations were also determined in the large-scale event. In both cases, THM formation occurred in the ponding water, without significant formation or degradation in the upper 3.0 m of the vadose zone. This study shows that MAR with chlorinated (<0.5 mg/L) desalinated seawater through sandy infiltration basins does not pose a threat to drinking water quality at this site

Skrb za pitno vodo

Safeguarding Drinking WaterLjubljana's water resources lie in the immediate vicinity of built-up urban areas or even below them. For decades, they have been safeguarded as water-protection areas, which are specified by implementing regulations. However, formal protection through regulations is insufficient if the goal is to manage these sources in a sustainable manner. One of the most important goals of sustainable management is maintaining suitable provision of fresh drinking water without using any technological procedures toVodni viri mesta Ljubljane so v neposredni bližini pozidanih mestnih zemljišč ali celo pod njimi. Že desetletja jih varujejo vodovarstvena območja. Eden od najpomembnejših ciljev trajnostnega upravljanja je ohranjanje ustrezne oskrbe z naravno pitno vodo brez tehnoloških postopkov njene priprave, kar Ljubljančani uvrščajo visoko na lestvici vrednot življenja v glavnem mestu Slovenije. Upravljanje ogroženih vodnih virov v urbanih okoljih zahteva celosten pristop in stalne aktivnosti. S pomočjo računalniških orodij znamo sisteme simulirati in tako pridobiti dodatna védenja o njihovem delovanju. Ta so v pomoč pri dolgoročnih odločitvah ali na primer ob okoljskih nesrečah. Za ustrezno načrtovanje so potrebna strokovna orodja, ki omogočajo zanesljive, pregledne in kvantitativne ocene učinkov ukrepov. Razpolaganje z zanesljivimi ocenami stanja in napovedmi olajšuje delo odločevalcem in tudi komunikacijo med deležniki. Povezava v monografiji predstavljenih postopkov in rezultatov v sistem izvedljivega upravljanja z vodnimi viri v Ljubljani je dosežek, ki je lahko zgled številnim podobnim okoljem, ne le v Sloveniji, ampak tudi širše

Themenheft „Grundwasserschutz und Grundwasserbewirtschaftung im Klimawandel“

Given the necessity to provide a substantial contribution to the climate protection goals borehole heat exchangers (BHE) and thermal energy storages (BTES) provide an efficient way to produce and store heat, especially in urban areas, but are for reasons of preventive groundwater protection usually rarely approved in areas of drinking water production. Numerical simulations of a BHE leakage in an aquifer used for drinking water production show that even at a distance of only 100 m between the BHE and the drinking water production well concentrations for most components used in commercially available heat transfer fluids do not exceed the limit values due to microbial degradation and dilution. Considering these results and in view of the ambition to reduce fossil primary energy sources by 80–95% by 2050 general distance requirements (currently &amp;gt;1000 m) therefore seem worthy of discussion, at least with regard to the drinking water pollution caused by leakages of BHE

Hydrodechlorination and hydrogenation of aromatic compounds over palladium on alumina in hydrogen-saturated water

The catalytic transformations of 1,2-dichlorobenzene, chlorobenzene, 4-chlorobiphenyl, γ-hexachlorocyclohexane (Lindane), naphthalene and phenanthrene were studied over palladium on alumina in hydrogen-saturated water (Pd/Al2O3/H2) at room temperature and ambient pressure. The chlorinated benzenes were rapidly hydrodechlorinated and Lindane was dehydrochlorinated to benzene. Partial or complete hydrogenation was observed for biphenyl and the polycyclic aromatic hydrocarbons. The phenanthrene ring was cleaved at the 9,10-position. In general dechlorination reactions were faster than hydrogenation reactions