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Publications

2022
Rosen, V. V. ; Garber, O. G. ; Chen, Y. Iodine determination in mineral water using ICP-MS: Method development and analysis of brands available in Israeli stores. 2022, 111, 104600. Publisher's VersionAbstract
Reliable iodine determination in drinking water samples has gained importance in the last few decades, mostly due to intensive use of both desalinized water that lacks several important nutritional elements, and bottled mineral water. ICP-MS is a sensitive method for iodine determination that must be performed under alkaline conditions because of the volatile nature of some iodine species. However, in water samples with high pH (>10), slow precipitation of calcium (Ca) and/or magnesium (Mg) carbonates leads to clogging of the ICP-MS nebulizer. We propose preventing this precipitation by adding the chelating agent ethylenediaminetetraacetic acid (EDTA) at 0.1% to a 2% ammonium hydroxide matrix. This concentration of EDTA sufficed for most drinking water samples studied, as long as a 1:1 molar ratio of EDTA to Ca+Mg concentration in the water was maintained. The limit of quantitation of the developed method for iodine was < 0.1 µg L−1. The average iodine concentration in various brands of bottled mineral water sold in Israel was relatively low (average value of seven brands ± standard deviation was 7.67 ± 6.38 µg I L−1). . Regular consumption of either desalinated water or bottled mineral water probably does not supply enough iodine to eliminate iodine deficiency in Israeli consumers. Therefore, continuous follow-up of the iodine status in both tap and bottled water is strongly recommended.
2021
Avidov, R. ; Varma, V. S. ; Saadi, I. ; Hanan, A. ; Lublin, A. ; Saldinger, S. S. ; Chen, Y. ; Laor, Y. Factors Influencing the Persistence of Salmonella Infantis in Broiler Litter During Composting and Stabilization Processes and Following Soil Incorporation. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2021, 5.Abstract
Broiler litter (BL), a by-product of broiler meat production, is frequently contaminated with Salmonella and other zoonotic pathogens. To ensure the safety of crop production chains and limit pathogen spread in the environment, a pre-treatment is desired before further agricultural utilization. The objective of this study was to characterize the effect of physico-chemical properties on Salmonella persistence in BL during composting and stabilization and following soil incorporation, toward optimization of the inactivation process. Thirty-six combinations of temperature (30, 40, 50, and 60 degrees C), water content (40, 55, and 70%; w/w), and initial pH (6, 7, and 8.5) were employed in static lab vessels to study the persistence of Salmonella enterica serovar Infantis (S. Infantis; a multidrug-resistant strain) during incubation of artificially-inoculated BL. The effect of aeration was investigated in a composting simulator, with controlled heating and flow conditions. Temperature was found to be the main factor significantly influencing Salmonella decay rates, while water content and initial pH had a secondary level of influence with significant effects mainly at 30 and 40 degrees C. Controlled simulations showed faster decay of Salmonella under anaerobic conditions at mesophilic temperatures (<45 degrees C) and no effect of NH3 emissions. Re-wetting the BL at mesophilic temperatures resulted in Salmonella burst, and led to a higher tolerance of the pathogen at increased temperatures. Based on the decay rates measured under all temperature, water content, and pH conditions, it was estimated that the time required to achieve a 7 log(10) reduction in Salmonella concentration, ranges between 13.7-27.2, 6.5-15.6, 1.2-4.7, and 1.3-1.5 days for 30, 40, 50, and 60 degrees C, respectively. Inactivation of BL indigenous microbial population by autoclaving or addition of antibiotics to which the S. Infantis is resistant, resulted in augmentation of Salmonella multiplication. This suggests the presence of microbial antagonists in the BL, which inhibit the growth of the pathogen. Finally, Salmonella persisted over 90 days at 30 degrees C in a Vertisol soil amended with inoculated BL, presumably due to reduced antagonistic activity compared to the BL alone. These findings are valuable for risk assessments and the formulation of guidelines for safe utilization of BL in agriculture.
Avidov, R. ; Varma, V. S. ; Saadi, I. ; Hanan, A. ; Yoselevich, I. ; Lublin, A. ; Chen, Y. ; Laor, Y. Physical and chemical indicators of transformations of poultry carcass parts and broiler litter during short term thermophilic composting. WASTE MANAGEMENT 2021, 119, 202-214.Abstract
Short-term on-site composting of poultry carcasses and broiler litter (BL) is considered as a feasible technology for pathogen elimination during events of mass mortality in poultry houses. However, factors related to mass losses and physical transformation of the poultry carcass, and associated emissions of volatile organic compounds (VOCs) and odors, have not been thoroughly evaluated. This study aims to characterize the degradation of separated carcass parts co-composted with BL and the associated air emissions during 30 days of enclosed composting at 50 degrees C with constant aeration. The study was carried out in lab-scale simulators using five mixtures containing feathers, rib bones, skins, breast muscles, and hearts and livers, prepared at a 1:2 volumetric ratio (carcass:BL). Dry mass losses reached 59.5, 41.1, 60.8 and 103.5% (based on weight) or 48.4, 29.6, 49.7, and 94.8% (based on CO2-C and NH3-N emissions), for rib bones, skins, breast muscles, and hearts and livers, respectively. Visually, most of the carcass parts were degraded, and the typical carcass odor had disappeared by the end of the 30 days. Out of 24 VOCs, dimethyl disulfide (DMDS) and dimethyl trisulfide (DMTS) contributed 80.7-88.3% of the total VOC flux, considering the partial contribution of each part to the emissions involved with the whole carcass. DMDS, DMTS, benzaldehyde, methanethiol, pentanoic acid, and NH3, contributed 90.5-97.9% of the odor activity values during composting. DMDS/DMTS ratio is suggested as a potential biomarker of stabilization and readiness of the compost for transportation toward further treatment or safe burial. (C) 2020 Elsevier Ltd. All rights reserved.
2020
De Nobili, M. ; Bravo, C. ; Chen, Y. The spontaneous secondary synthesis of soil organic matter components: A critical examination of the soil continuum model theory. APPLIED SOIL ECOLOGY 2020, 154.Abstract
The Soil Continuum Model questions the occurrence of any independent natural process of secondary synthesis that generates compounds structurally distinct from plant or microbial metabolites. This review shows that a vast volume of interdisciplinary scientific evidence supports the formation of relevant non-pre-existing complex molecules exhibiting various types of structures. These molecules form during degradation and decay of biological cell components. The spontaneous abiotic and enzymatically catalysed reactions of components of organic residues and of their oxidative decomposition products suggested by state-of-the-art studies are indeed those proposed by most of the classical descriptions of humification. The review also highlights the chemically active role of pedofauna, explaining why the apparently harsh conditions of alkaline extraction of HS cannot be considered un-natural. Many insects and larvae feeding on foliage of plants with a high content of tannins have a midgut pH above 9. Albeit, reducing conditions are often maintained to avoid oxidation, peroxidases are active in the intestinal tract and pass on to feces. Polyphenols are then immediately enzymatically oxidized to their reactive quinone form, once feces are excreted and exposed to oxygen. Implications of our current knowledge on the reactivity of plant components in soil are discussed in relation with the present state of the art research on humic substances. Contrary to claims by the Soil Continuum Model theory, complimentary modern approaches need to be used to understand the complexity of soil organic matter.
Tolkin, S. ; Chen, Y. ; Tarchitzky, J. Humic acid, dextran, and valeric acid representing macromolecules similar to compounds prevailing in treated wastewater induce soil hydrophobicity. JOURNAL OF SOILS AND SEDIMENTS 2020, 20, 3548-3556.Abstract
Purpose Organic compounds originating from treated wastewater and soil texture have been reported to be the dominant factors influencing soil hydrophobicity. It is the aim of this investigation to elaborate the role of humic acid, dextran, and valeric acid, representing dissolved organic matter, polysaccharides, and fatty acids, respectively, as well as imitating their activity in inducing soil sub-critical water repellency induced by treated wastewater irrigation. Materials and methods The relationships between three model compounds imitating fractions of dissolved organic matter commonly found in treated wastewater, soil texture in relation to water repellency, were investigated. Three types of organic molecules, five soil mixtures with different specific surface areas, and three different organic compounds, as well as a mixture of the three, were tested. Results and discussion After 14-15 of wetting and drying cycles, low levels (sub-critical hydrophobicity) of water repellency developed in all soil mixtures were subjected to applications of several solutions of organic compounds, in comparison with a freshwater control. The highest degree of water repellency was exhibited by the soil with the lowest clay content (lowest specific surface area) and it decreased with increasing clay content (increasing specific surface area). Conclusions The order of intensity of sub-critical water repellency levels induced by the organic compounds was consistent, yet independent of soil texture. However, soil texture exhibited large influence on soil hydrophobicity in response to the various organic chemicals. Humic acid, the closest in structure to organic matter prevailing in treated wastewater, exhibited the largest effect in inducing soil hydrophobicity.
2019
Olk, D. C. ; Bloom, P. R. ; Perdue, E. M. ; McKnight, D. M. ; Chen, Y. ; Farenhorst, A. ; Senesi, N. ; Chin, Y. - P. ; Schmitt-Kopplin, P. ; Hertkorn, N. ; et al. Environmental and agricultural relevance of humic fractions extracted by alkali from soils and natural waters. Journal of Environmental Quality 2019, 48, 217-232. Publisher's VersionAbstract
To study the structure and function of soil organic matter, soil scientists have performed alkali extractions for soil humic acid (HA) and fulvic acid (FA) fractions for more than 200 years. Over the last few decades aquatic scientists have used similar fractions of dissolved organic matter, extracted by resin adsorption followed by alkali desorption. Critics have claimed that alkali-extractable fractions are laboratory artifacts, hence unsuitable for studying natural organic matter structure and function in field conditions. In response, this review first addresses specific conceptual concerns about humic fractions. Then we discuss several case studies in which HA and FA were extracted from soils, waters, and organic materials to address meaningful problems across diverse research settings. Specifically, one case study demonstrated the importance of humic substances for understanding transport and bioavailability of persistent organic pollutants. An understanding of metal binding sites in FA and HA proved essential to accurately model metal ion behavior in soil and water. In landscape-based studies, pesticides were preferentially bound to HA, reducing their mobility. Compost maturity and acceptability of other organic waste for land application were well evaluated by properties of HA extracted from these materials. A young humic fraction helped understand N cycling in paddy rice (Oryza sativa L.) soils, leading to improved rice management. The HA and FA fractions accurately represent natural organic matter across multiple environments, source materials, and research objectives. Studying them can help resolve important scientific and practical issues. Copyright © American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.
Ashkenazi, E. ; Chen, Y. ; Avni, Y. Olive tree survival and adaptation to the harsh growing conditions in the arid desert environment of the Negev Highlands, Southern Israel. Israel Journal of Plant Sciences 2019, 65, 147-152. Publisher's VersionAbstract
Twenty-three olive trees were found to grow in traditional orchard sites in the Negev Highlands desert, southern Israel. Their location was marked on maps, and their growth, morphology, biology, preservation and survival was monitored. Some of them are presently maintained by the Bedouin population of the Negev, whereas others seemed to have survived from earlier periods. The average annual rainfall in this region is 90-130 mm. Most of the orchards were deliberately planted in preexisting agricultural plots, built during the Byzantine and Early Muslim era (3rd-8th centuries CE). They were irrigated by harvesting runoff water. The Byzantine era was the most populated period in the Negev Highlands, when wine and olive oil were the main horticultural products. A variety of domesticated fruit trees are found in the present abandoned orchards: olive, fig, grapevine, pomegranate, almond, date palm, carob, pistachio and bitter orange. The trees have not been artificially irrigated for at least seven decades. Nevertheless, most of them continue to flourish and bear fruit. We focused on understanding the abandoned olive trees' survival and adaptation mechanisms. Olive trees growing was a favorite crop to Byzantine farmers due to the significant economic value of olive oil and good adaptation to the environmental conditions in the Negev Highlands. © Koninklijke Brill NV, Leiden, 2018.
Olk, D. C. ; Bloom, P. R. ; De Nobili, M. ; Chen, Y. ; McKnight, D. M. ; Wells, M. J. M. ; Weber, J. Using humic fractions to understand natural organic matter processes in soil and water: Selected studies and applications. Journal of Environmental Quality 2019, 48, 1633-1643. Publisher's VersionAbstract
Natural organic matter (NOM) plays key environmental roles in both aquatic and soil systems. A long-standing approach for evaluating NOM composition and activity is to extract soils with alkali solutions to obtain humic substances, namely humic acids (HA), and fulvic acids (FA), or to briefly expose isolated fractions of dissolved organic matter to alkali. Critics have claimed these methods create laboratory artifacts and are thus unsuitable for studying NOM behavior in field conditions. In response, we describe case studies in which humic fractions were analyzed to identify significant processes in environmental or agricultural issues. Specifically, humic fractions played a key role in maintaining toxic levels of arsenic (As) in drinking water supplies in South and Southeast Asia. Elsewhere, binding reactions of FA and HA with prions were shown to provide a plausible mechanism for variable persistence of prion infectivity across soil types. Humic substances were also shown to enhance iron (Fe) uptake by plants in solution culture and field conditions. Their specific binding sites for mercury (Hg) as determined in laboratory conditions enabled accurate modeling of soil Hg binding under varying conditions. A young HA fraction reproduced in controlled conditions the capacity of animal manure to maintain potassium (K) availability in strongly K-fixing field soils, leading to development of a commercially successful humic-K fertilizer. Humic fractions accurately represented NOM across multiple settings and research objectives while providing novel opportunities for advanced analyses. The study of humic fractions has helped resolve scientific and practical issues in aquatic and soil systems. © 2019 The Author(s).
Ashkenazi, E. ; Avni, Y. ; Chen, Y. The vitality of fruit trees in ancient Bedouin orchards in the Arid Negev Highlands (Israel): Implications of climatic change and environmental stability. Quaternary International 2019. Publisher's VersionAbstract
Thirty-seven sites with fruit tree orchards were found in the arid Negev Highlands of southern Israel. A variety of domesticated fruit trees were planted in these orchards, including date palm, fig, olive, pomegranate, almond, carob, pistachio, grapevine and bitter orange. The orchards were irrigated only by runoff water accumulating in runoff-harvesting systems built during the Byzantine and Early Muslim eras, some 1000–1500 years ago, which, despite their antiquity, are still vivid and occasionally fruit bearing today. The oldest olive trees seem to be direct descendants of trees planted during Byzantine times, whereas the youngest trees were planted by the Bedouin population of the Negev Highlands in the last few decades. The fact that the Bedouin population, with very little experience in agriculture, has succeeded to cultivate a large variety of fruit trees in the present harsh arid climate utilizing the historical agricultural installations has important environmental implications. It indicates that the original builders of the desert agriculture systems were highly sophisticated in transforming desert soil into arable land. However, this was achieved through hard labor, involving the construction of a vast number of stone dams and agricultural terraces to divert channels, and the clearing of rocky surfaces. This huge effort indicates that the climate and environment prevailing during the Byzantine–Early Muslim eras was equally harsh and arid; otherwise, the invested labor would not have been justified. We conclude that the Byzantine farmers, with their greater agricultural experience and long heritage in dry land agriculture, have achieved greater success than today Bedouin population, at cultivating of fruit trees under the harsh conditions of the Negev Highlands. Therefore we deduce that the ancient desert agriculture was not the outcome of better climate; rather, the climate prevailing during the relevant historical times was probably dry and harsh, much like today. The fact that the Bedouin population in that geograghical area is cultivating orchards utilizing the same constructions, and technologies indicates that the present environmental and climatic conditions were are suitable for practicing desert agriculture and have hardly changed since the Byzantine era. © 2019 Elsevier Ltd and INQUA
2018
Ben Mordechay, E. ; Tarchitzky, J. ; Chen, Y. ; Shenker, M. ; Chefetz, B. Composted biosolids and treated wastewater as sources of pharmaceuticals and personal care products for plant uptake: A case study with carbamazepine. Environmental Pollution 2018, 232, 164-172. Publisher's VersionAbstract
Irrigation with treated wastewater (TWW) and application of biosolids to arable land expose the agro-environment to pharmaceuticals and personal care products (PPCPs) which can be taken up by crops. In this project, we studied the effect of a carrier medium (e.g., biosolids and TWW) on plant (tomato, wheat and lettuce) uptake, translocation and metabolism of carbamazepine as a model for non-ionic PPCPs. Plant uptake and bioconcentration factors were significantly lower in soils amended with biosolids compared to soils irrigated with TWW. In soils amended with biosolids and irrigated with TWW, the bioavailability of carbamazepine for plant uptake was moderately decreased as compared to plants grown in soils irrigated with TWW alone. While TWW acts as a continuous source of PPCPs, biosolids act both as a source and a sink for these compounds. Moreover, it appears that decomposition of the biosolids in the soil after amendment enhances their adsorptive properties, which in turn reduces the bioavailability of PPCPs in the soil environment. In-plant metabolism of carbamazepine was found to be independent of environmental factors, such as soil type, carrier medium, and absolute amount implemented to the soil, but was controlled by the total amount taken up by the plant. Bioavailability of PPCPs originated from biosolids amendment is lower than the bioavailability of those introduced by irrigation with treated wastewater. © 2017 Elsevier Ltd
Rosen, V. ; Chen, Y. Effects of compost application on soil vulnerability to heavy metal pollution. Environmental Science and Pollution Research 2018, 25, 35221-35231. Publisher's VersionAbstract
Soil vulnerability to heavy metal pollution is low in soils exhibiting an ability to strongly adsorb heavy metals on their geochemical fractions. Organic matter (OM) is among other components of soils, one of the most effective sorbing fractions. Compost addition is often used for soil remediation thereby enriching the soil with OM. However, compost is often enriched with heavy metals and thereby may induce adverse effects on the soil and plants growing in them. Compost-derived dissolved organic matter (DOM) can mobilize heavy metals. The balance between two contrasting effects of compost—mobilization and immobilization of heavy metals—was studied under the conditions of adsorption–desorption batch experiment. Metal adsorption to different geochemical fractions of soil treated with compost was examined by a combined batch-adsorption experiment and a sequential extraction procedure. Compost-derived DOM mobilized Cu at low loading levels, whereas adsorption of Cd and Pb was not decreased by DOM application. Compost was found to be a source of an important reducible oxides fraction (RO—sorbing and fixation fraction) and also of the OM geochemical fractions that most commonly immobilizes heavy metals. The Langmuir and Freundlich models employed in our study exhibited a good fit for most of data the experimental data obtained on bulk samples. Adsorption of the metals on operationally defined geochemical fractions was described by a linear function in several experimental instances. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
Green, O. ; Katz, S. ; Tarchitzky, J. ; Chen, Y. Formation and prevention of biofilm and mineral precipitate clogging in drip irrigation systems applying treated wastewater. Irrigation Science 2018, 36, 257-270. Publisher's VersionAbstract
Pressure-irrigation systems and, in particular, micro-irrigation provide an effective methodology for increasing irrigation efficiency. However, emitter clogging is a major problem in micro-irrigation systems, especially under irrigation with treated wastewater (TWW). Currently, farmers treat their irrigation system by periodical application of solutions of chemicals or washing the lateral lines. The aim of this study was to characterize treatments for the prevention of clogging in drip irrigation systems utilizing different qualities of TWW (secondary and tertiary TWW). A model system was designed and assembled to compare the flow rate (FR), fouling accumulation and fouling composition in laterals and drippers subjected to different treatments. Under irrigation with secondary TWW, control treatment function decreased rapidly while chemical treatment prolonged proper function of the drippers by maintaining a normal FR and coefficient of variation (CV). Wash treatment improved to some extent the irrigation function. Under irrigation with tertiary TWW the function of all treatments was significantly better than that of the secondary treatments. The total suspended solids level was found to be a significant factor in the mechanism of clogging formation according to biofouling development. The deposit chemical characterization could shed light on the mode of growth mechanism and properties of the biofouling. In general, oxidation treatments using hydrogen peroxide or hypochlorite acid were found to eliminate biofouling and in accordance also prevented clogging. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
Rosen, V. V. ; Garber, O. G. ; Chen, Y. Magnesium deficiency in tap water in Israel: The desalination era. Desalination 2018, 426, 88-96. Publisher's VersionAbstract
Water desalination has been extensively developed in Israel, particularly in the last decade. The desalination process provides fresh water that typically lacks minerals, and among these are ions that are essential to human health and/or to agricultural production, such as Mg. We analyzed 28 tap water samples originating from different cities across Israel to document their concentrations of Mg and other elements. The data from this survey (summer 2016) were compared with the results of similar observations conducted in 2008. Regarding toxic elements, tap water across Israel does not pose any health risk for consumers and may be used as drinking water without any household pretreatment. This condition has not changed since 2008. However, the problem of Mg deficiency due to the use of desalinated water was observed in about half of the sampling locations in 2016, whereas no Mg deficiency had been detected in 2008. Moreover, household filtration of tap water prior to consumption as drinking water may worsen the situation due to the Mg status resulting from rejection of this ion; this could be harmful to the consumer, particularly under prolonged exposure. © 2017 Elsevier B.V.
Weber, J. ; Chen, Y. ; Jamroz, E. ; Miano, T. Preface: humic substances in the environment. Journal of Soils and Sediments 2018, 18, 2665-2667. Publisher's Version
Katz, S. ; Wagner, M. ; Horn, H. ; Tarchitzky, J. ; Chen, Y. Size and stability of suspended aggregates in municipal effluents containing montmorillonite, bacteria and fulvic acid. Irrigation Science 2018, 36, 203-216. Publisher's VersionAbstract
Utilizing treated wastewater (TWW) for irrigation results in biological and chemical deposits. TWW components such as bacteria and suspend minerals interact under different environmental conditions, forming aggregates varying in size and stability that may adversely affect water flow in drippers. Our aim in this study was to characterize aggregates’ size and stability in suspensions of bacteria and clay particles, under different conditions prevailing in TWW. Flocculation value tests, thermal analysis, microscopy and particle size distribution were used to measure bacterial–clays interaction in suspension. Our results showed suspension stability increase with an increase in bacterial population. Dissolved organic carbon (DOC) produced by bacteria or added as fulvic acid was found to be the most important parameter involved in determining aggregate size and stability under similar environmental condition. The presence of these components most commonly resulted in higher stability of the suspension, mainly smaller particles in suspension. A novel measurement aimed to determine size and stability parameters for suspended particles has been established and was found to be useful in predicting suspended compound interactions. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
Avidov, R. ; Saadi, I. ; Krasnovsky, A. ; Medina, S. ; Raviv, M. ; Chen, Y. ; Laor, Y. Using polyethylene sleeves with forced aeration for composting olive mill wastewater pre-absorbed by vegetative waste. Waste Management 2018, 78, 969-979. Publisher's VersionAbstract
Composting in closed polyethylene sleeves with forced aeration may minimize odor emissions, vectors attraction and leachates associated with open windrows. The present study demonstrates the use of this system for composting olive mill wastewater (OMW), the undesired stream associated with the olive milling industry. A polyethylene sleeve of 1.5-m diameter and ca. 20-m long was packed with shredded municipal green waste which was pre-soaked in OMW for 72 h. Process conditions were controlled by means of a programmable logic controller (PLC) equipped with temperature and oxygen sensors. Thermophilic temperatures (>45 °C) were maintained for one month followed by temperatures in the range of 30–40 °C, ca. 20 °C above ambient temperature, for a period of 3.5 months. Oxygen levels were controlled and the system was kept aerobic. Water content gradually decreased with sufficient levels for efficient composting. The finished compost was non-phytotoxic to Cress (Lepidium sativum L.) in a lab bioassay. It was also found suitable as an ingredient in peat, tuff, and coir based growing media, evaluated by plant growth tests with basil and ornamental plants. The viability of this approach for disposing off OMW is much dependent on the liquid absorption capacity of the vegetative waste. © 2018 Elsevier Ltd
2017
Lichner, L. ; Rodný, M. ; Marschner, B. ; Chen, Y. ; Nadav, I. ; Tarchitzky, J. ; Schacht, K. Comparison of various techniques to estimate the extent and persistence of soil water repellency. Biologia (Poland) 2017, 72, 982-987. Publisher's VersionAbstract
New techniques to estimate the extent and persistence of soil water repellency (SWR) were compared with commonly used techniques in assessing the results taken in the long-term agricultural experimental orchards in northern Israel irrigated with either freshwater (FW), primary treated wastewater (WW) or (secondary or tertiary) treated wastewater (TWW), where SWR induced by irrigation was registered (Ha Ma'apil, Neve Etan, and Shafdan). The extent of SWR was assessed by the repellency index RI, combined repellency index RI c and modified repellency index RI m . The persistence of SWR was assessed by the water drop penetration time WDPT and water repellency cessation time WRCT. Soils from different textural classes were classified as slightly to strongly water repellent according to WDPT or RI values. Relationship between RI c and RI values can be well fitted by the linear equation, i.e., RI c could be a good substitute for RI. Relationships between WRCT and WDPT values as well as RI m and RI c or RI values cannot be accurately described by the linear equation, i.e., RI m is not a good substitute for RI for the values taken in this study. © 2017 Institute of Botany, Slovak Academy of Sciences 2017.
Avidov, R. ; Saadi, I. ; Krassnovsky, A. ; Hanan, A. ; Medina, S. ; Raviv, M. ; Chen, Y. ; Laor, Y. Composting municipal biosolids in polyethylene sleeves with forced aeration: Process control, air emissions, sanitary and agronomic aspects. Waste Management 2017, 67, 32-42. Publisher's VersionAbstract
Composting in polyethylene sleeves with forced aeration may minimize odor emissions, vectors attraction and leachates associated with open windrows. A disadvantage of this technology is the lack of mixing during composting, potentially leading to non-uniform products. In two pilot experiments using biosolids and green waste (1:1; v:v), thermophilic conditions (>45 °C) were maintained for two months, with successful control of oxygen levels and sufficient moisture. Emitted odors declined from 1.5–3.8 × 105 to 5.9 × 103–2.3 × 104 odor units m−3-air in the first 3 weeks of the process, emphasizing the need of odor control primarily during this period. Therefore, composting might be managed in two phases: (i) a closed sleeve for 6–8 weeks during which the odor is treated; (ii) an open pile (odor control is not necessary). Reduction of salmonella, E. coli and coliforms was effective initially, meeting the standards of “Class A” biosolids; however, total and fecal coliforms density increased after opening the second sleeve and exceeded the standard of 1000 most probable number (MPN) per g dry matter. Compost maturity was achieved in the open piles following the two sleeves and the final compost was non-phytotoxic and beneficial as a soil additive. © 2017 Elsevier Ltd
Frenkel, C. ; Hadar, Y. ; Chen, Y. Laboratory-scale production and purification of the iron chelator rhizoferrin: A novel Fe supplier to plants. Israel Journal of Plant Sciences 2017, 64, 136-144. Publisher's VersionAbstract
Rhizopus arrhizus was grown in an iron-free nutrient solution growth medium. Mass production of the siderophores was achieved in a short time by continuous growth of the fungi: after the secretion of the siderophores into the growth medium the spent medium was collected and replaced by a fresh medium while the fungus mat was kept in the flask. The medium exchange was repeated several times and the optimal time for the collection of the siderophore was found to be when the fungus was fully developed, usually about 3 days after the exchange. It was found that it is feasible to grow the fungi continuously for five growth periods, after which the fungus culture becomes too old and collapses. The siderophore was isolated and cleaned from the spent medium using a series of columns on an FPLC at room temperature. Additional tests were used to verify the existence of the siderophore in the solution. The concentrations of rhizoferrin in the various fractions was measured using an exchange reaction between the siderophore and that of an added chelate solution (CAS) while employing a series of dilutions of the CAS. For a precise analytical determination of the siderophore rhizoferrin, Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FTICR-MS) was used to validated that the siderophore is indeed rhizoferrin which has been structurally identified earlier. © 2017 by Koninklijke Brill NV, Leiden, The Netherlands.
Qian, J. ; Horn, H. ; Tarchitzky, J. ; Chen, Y. ; Katz, S. ; Wagner, M. Water quality and daily temperature cycle affect biofilm formation in drip irrigation devices revealed by optical coherence tomography. Biofouling 2017, 33, 211-221. Publisher's VersionAbstract
Drip irrigation is a water-saving technology. To date, little is known about how biofilm forms in drippers of irrigation systems. In this study, the internal dripper geometry was recreated in 3-D printed microfluidic devices (MFDs). To mimic the temperature conditions in (semi-) arid areas, experiments were conducted in a temperature controlled box between 20 and 50°C. MFDs were either fed with two different treated wastewater (TWW) or synthetic wastewater. Biofilm formation was monitored non-invasively and in situ by optical coherence tomography (OCT). 3-D OCT datasets reveal the major fouling position and illustrate that biofilm development was influenced by fluid dynamics. Biofilm volumetric coverage of the labyrinth up to 60% did not reduce the discharge rate, whereas a further increase to 80% reduced the discharge rate by 50%. Moreover, the biofilm formation rate was significantly inhibited in daily temperature cycle independent of the cultivation medium used. © 2017 Informa UK Limited, trading as Taylor & Francis Group.