bluuebunny/crossref_metadata_2025 huggingface dataset:
Small Floodplain Reservoirs in the Face of Climate Change—Sink or Source of Nutrients?
Authors: Gmitrowicz-Iwan Joanna , Ligęza Sławomir , Pranagal Jacek , Smal Halina , Olenderek Heronim
Published: December 2020

Despite various water protection measures, good water quality and reduction of nutrient loads seem very distant goals, largely due to limited knowledge of processes occurring in river valleys. Our study aimed at establishing the role of small floodplain reservoirs in the eutrophication processes, in the face of recent climate changes. The content of phosphorus and nitrogen compounds was determined in sediments and water of small floodplain reservoirs, (the Vistula River Valley, Poland) using spectrophotometric and Kjeldahl’s method. Nutrient loads in sediments were linked to the texture and total organic carbon content. Seasonal changes in water quality were strictly connected to changing weather conditions, flood and drought. The concentrations of PO43− and NO3− were found to rise after summer flooding. Increases in NH4+, total phosphorus (TP) and total nitrogen (TN) were correlated with the surface water area reduction in the reservoirs, which during the year of the study was on average 62%. Therefore, small floodplain reservoirs could be considered simultaneously as sinks and sources of nutrients. On the one hand, they accumulate P and N compounds carried by the river during the flood. On the other hand, climate change cause that small floodplain reservoirs may be responsible for enhanced biomass production.
Performance, Energy and Cost of Produced Water Treatment by Chemical and Electrochemical Coagulation
Authors: Khor Chia Miang , Wang Jinwen , Li Minghua , Oettel Bruce A. , Kaner Richard B. , Jassby David , Hoek Eric M. V.
Published: December 2020

The separation performance, energy demand, and operating costs of electro-coagulation (EC) are compared to conventional chemical coagulation for oil–water separation using a simulated oil- and gas-produced water matrix. An iron-based chemical coagulant and sacrificial iron electrodes are evaluated. Effluent turbidity, chemical oxygen demand (COD), total organic carbon (TOC), and oil and grease (O&G) removal were determined for various coagulant concentrations and reaction times and current densities. Chemical coagulation produced superior turbidity removal when scaled by the total iron dose. At lower iron doses (<500 mg/L), chemical coagulation yielded better COD, turbidity, and O&G removal. However, chemical coagulation was unable to effectively remove contaminants to meet the offshore discharge limit of 29 ppm O&G. At higher iron doses, EC was more effective at removing COD and O&G. The energy consumption of EC was found to be much higher even when factoring in the energy of production, transporting, and mixing of chemical coagulants, but the overall cost of EC was approximately half the cost of chemical coagulation, and more effective at O&G removal.
Mapping Management Zones Based on Soil Apparent Electrical Conductivity and Remote Sensing for Implementation of Variable Rate Irrigation—Case Study of Corn under a Center Pivot
Authors: Serrano João , Shahidian Shakib , Marques da Silva José , Paixão Luís , Moral Francisco , Carmona-Cabezas Rafael , Garcia Sónia , Palha José , Noéme João
Published: December 2020

Climate change, especially the trend towards global warming, will significantly affect the global hydrological cycle, leading to a general reduction of the water available for agriculture. In this scenario, it is essential that research should focus on the development of ‘water saving’ techniques and technologies. This work summarizes the methodology followed in a project for large scale implementation of variable rate irrigation (VRI) systems using center pivots in corn crop. This is based on technologies for monitoring (i) soil electrical conductivity (ECa) and altimetry, (ii) soil moisture content, (iii) vegetation indices (Normalized Difference Vegetation Index, NDVI) obtained from satellite images, and automatic pivot travel speed control technologies. ECa maps were the basis for the definition of first homogeneous management zones (HMZ) in an experimental corn field of 28 ha. NDVI time-series were used to establish the subsequent HMZ and the respective dynamic prescription irrigation maps. The main result of this study was the reduction of spatial yield variability with the VRI management in 2017 compared to the conventional irrigation management. This study demonstrates how a relatively simple approach could be designed and implemented on a large scale, which represents an important and sustainable contribution to the resolution of practical farmer issues.
Post-Calibration Uncertainty Analysis for Travel Times at a Naval Weapons Industrial Reserve Plant
Authors: Ahmmed Bulbul , James Scott C. , Yelderman Joe
Published: December 2020

The Naval Weapons Industrial Reserve Plant (NWIRP) in McGregor, Texas began manufacturing explosives in 1980 and several hazardous chemicals were discovered in lakes and streams surrounding the site in 1998. Contaminants traveled to local lakes and streams much faster than initially predicted. This research estimated contaminant travel times and identified locations where monitoring wells should be installed to yield the greatest reductions in uncertainties in travel-time predictions. To this end, groundwater and particle-tracking models for NWIRP site were built to predict hydraulic heads and contaminant travel times. Next, parameter (hydraulic conductivities) uncertainties, parameter identifiabilities, observation (hydraulic heads) worth, and predictive (contaminant travel times) uncertainties were quantified. Parameter uncertainties were reduced by up to 92%; a total of 19 of 158 parameters were at least moderately identifiable; travel-time uncertainties were reduced up to 92%. Additionally, travel-time predictions and post-calibration parameter distributions were generated using the null-space Monte Carlo (NSMC) technique. NSMC predicted that conservative tracers exited the flow system within a year, which matches with field data. Finally, an observations-worth analysis found that additional 11 more measurements would reduce travel-time uncertainties by factors from 1.04 to 4.3 over existing data if monitoring wells were installed at the suggested locations.
The Impacts of Arable Land per Farmer on Water Markets in China
Authors: Wang Yahua , Xu Maosen , Zhu Tingju
Published: December 2020

Water trading markets have been introduced in many countries as a means to alleviate water scarcity. However, the performance of water markets varies greatly across different countries, and in only very few countries do they work well. In this study, a two-sector water rights trading model is developed and applied to a case study in China. The results suggest that arable land per farmer is a key factor that affects the performance of water markets in China. This is positively correlated with traded water volume, with the market’s economic efficiency, and with the social welfare the market brings. Although the model simulation ignores other factors, this problem can be solved by selecting a suitable research area. These findings suggest that water markets may be less likely to be effective in countries with small arable land per farmer.
Technological Reliability and Efficiency of Wastewater Treatment in Two Hybrid Constructed Wetlands in the Roztocze National Park (Poland)
Authors: Micek Agnieszka , Jóźwiakowski Krzysztof , Marzec Michał , Listosz Agnieszka
Published: December 2020

The paper presents the results of a 3-year study on the technological reliability and the efficiency of typical domestic wastewater treatment in two hybrid constructed wetland systems (CWs) located in the area of the Roztocze National Park (Poland). The studied objects consist of an initial settling tank and a system of two beds of the vertical flow (VF) and horizontal flow (HF) (VF–HF) type with reed and willow. The wastewater flow rate in the constructed wetlands systems (CWs) was 0.4 and 1.0 m3/d, respectively. During the study period (2017–2019) 20 series of analyses were performed and 60 wastewater samples were collected. Based on the obtained results the effects of pollutant removal and the technological reliability were determined, which were specified with the Weibull method. The average efficiency of biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) removal was 96–99%. Slightly lower effects were obtained in the case of total phosphorus (TP) removal (90–94%), as well as for total suspended solids (TSS) (80–87%) and total nitrogen (TN) (73–86%) removal. The analysed CWs were characterised by 100% technological reliability for BOD5 and COD, as well as a good reliability for TSS and TP (87–100%) but slightly lower for TN removal (35–89%). Hybrid CWs of VF–HF type should be recommended to use in protected areas for wastewater treatment and water resources quality protection.
Particle Size and Pre-Treatment Effects on Polystyrene Microplastic Settlement in Water: Implications for Environmental Behavior and Ecotoxicological Tests
Authors: Eitzen Lars , Ruhl Aki Sebastian , Jekel Martin
Published: December 2020

Microplastic (MP) particle dispersions used in many recent publications covering adsorption or toxicological studies are not characterized very well. The size distribution of polydisperse dispersions is highly dependent on the agglomeration processes and influences experimental outcomes. Therefore, pre-treatment is a prerequisite for reproducibility. In this study, manual/automated shaking and ultrasonic treatment as different mechanical dispersion techniques were applied for the dispersion of cryomilled polystyrene (PS). Particle numbers and size distribution of dispersions were analyzed by a light extinction particle counter and the dispersion efficiency (ED) as the ratio between calculated volume and theoretical volume of suspended particles was used to compare techniques. PS dispersions (20 mg/L) treated for 90 min in an ultrasonic bath (120 W, 35 kHz) were evenly dispersed with a particle concentration of 140,000 particles/mL and a high reproducibility (rel. SD = 2.1%, n = 6). Automated horizontal shaking for 754 h (250 rpm) reached similar particle numbers (122,000/mL) but with a lower reproducibility (rel. SD = 9.1%, n = 6). Manual shaking by hand dispersed the lowest number of particles (55,000/mL) and was therefore found to be unsuitable to counteract homo-agglomeration. ED was calculated as 127%, 104% and 69% for ultrasonic treatment, horizontal shaking and manual shaking, respectively, showing an overestimation of volume assuming spherical shaped particles.
Short-Term Peak-Shaving Operation of Head-Sensitive Cascaded Hydropower Plants Based on Spillage Adjustment
Authors: Liao Shengli , Zhang Yan , Liu Benxi , Liu Zhanwei , Fang Zhou , Li Shushan
Published: December 2020

There are many cascaded hydropower plants with poor regulation performance and sensitive water heads accompanied by water spillage during the wet season. Faced with the increasing load peak–valley differences, it is necessary to tap the peak-shaving potential of such head-sensitive cascaded hydropower plants (HSCHPs) because relying solely on hydropower plants with better regulation performance for peak shaving is inadequate. To address the modeling, solving, and water spillage treatment difficulties posed by HSCHPs, a new short-term peak-shaving method based on spillage adjustment is introduced. First, fuzzy cluster analysis is used to determine when to release more water spillage by automatically identifying valley periods of the daily load curve. Furthermore, a spillage adjustment strategy, implemented through an easy gate operation, is adopted to readjust the water release during each period of the load curve. The ratio of the water spillage released in advance in a certain period to its total water spillage is defined as the water spillage ratio (WSR) of the period. Finally, a mixed-integer linear programming model linearized by special ordered sets of type two is solved to determine the optimal WSRs, which achieves the optimal peak-shaving effect. HSCHPs in the Hongshui River Basin during the wet season were selected as case studies. The results demonstrate that the proposed method can achieve a good peak-shaving effect without significantly reducing the power generation and adding additional water spillage.
Cohesive Channel Response to Watershed Urbanization: Insights from the Sand River, Aiken SC
Authors: Sullivan Jessica , Grubb Joshua , Willis Ronald , Boozer Derek , Flickinger Brooks , Dixon Christopher Eric
Published: December 2020

Stream channel degradation is among the most widely documented symptoms of urban stream syndrome arising from watershed urbanization. Nevertheless, our present understanding of space and time scales associated with channel response to urbanization is poorly constrained and largely limited to assessments of non-cohesive systems. The purpose of this study is to assess the evolution of a cohesive, ephemeral river channel in response to watershed urbanization. The assessment of historical images document the stable, pre-urbanized channel conditions from 1870 to 1930. Historical assessments revealed a 131% increase in urbanized watershed area from 1930 to 1992, and a minimal increase in urbanized extent from 1992 to 2012. A 2012 lidar dataset was used to generate the modern long-channel profile, to reconstruct cross-channel profiles observed in 2002, and to estimate the volume flux of sediment removed from the channel from 1930 to 1992, and from 1992 to 2012. The long-channel profile reveals incision of up to 35 m in response to urbanization from 1930 to 1992. Cross-channel profiles reveal incision and widening of 2.5 and 3 m, respectively, from 2002 to 2012. Volume flux estimates indicate erosion rates of 9000 m3/yr during the first 62 years of the study period, and a flux of 4000 m3/yr after installation of stormwater control measures in 1992. Collectively, our findings highlight a cohesive channel that has undergone substantial incision and widening at a rate of ~0.20 m/yr since 1930, and the channel continues to adjust. Hence, we contend that the channel has not yet attained a new equilibrium “shape” at 82 years after peak land use change within the watershed, and that the channel will continue to adjust its shape until this new balance is achieved.
Effect of Independent Variables on Urban Flood Models
Authors: Geng Yanfen , Zhu Baohang , Zheng Xin
Published: December 2020

The simulation accuracy of urban flood models is affected by independent variables describing terrain resolution and artificial land cover. An evaluation of these effects could provide suggestions for the improvement of simulation accuracy when the available terrain resolutions and representation methods of land cover are different. This paper focused on exploring and evaluating these effects on simulation accuracy using two indicators, relative depth accuracy (RDA) and relative area accuracy (RAA). The study area was the Nanjing Jianye district in China, which has experienced extensive urbanization. Designed rainfall (2 and 10 year return periods) and three terrain resolutions (17, 35, and 70 m) were used in this paper. Building blocks (BB), road drainage (RD), and a combination of both (BB + RD) were compared to present the effect of artificial land cover. Real flood events were initially simulated as a model verification case, and hypothetic modeling scenarios were simulated to evaluate the effects of different resolutions and representation methods. The results indicate that the effect of terrain resolutions on simulation accuracy was more obvious than that of artificial land cover in the study area. In this paper, 20–30% higher accuracy could be achieved in the 35 m resolution model with respect to the 70 m resolution model. A relative accuracy of 94% was achieved in the 17 m resolution model when using the BB method, which was 5% higher than that using the RD method. This paper shows that evaluating the effects of terrain resolution and artificial land cover is effective and helpful for improving the simulation accuracy of urban flood models in extensively urbanized districts.
Integrated Assessment—How Does It Help Unpack Water Access by Marginalized Farmers?
Authors: Hamilton Serena H. , Merritt Wendy S. , Das Mahanambrota , Rahman M. Wakilur , Bhuiya Sumana S. , Carter Lucy , Cosijn Michaela , Roth Christian H. , Singha Sambhu , Syme Geoffrey J.
Published: December 2020

Water is critical to the lives and livelihoods of rural communities in developing countries; however, access to water can be inequitable within communities. This paper uses a generalized integrated assessment approach to explore the determinants of water access by marginalized farmers in two villages in coastal Bangladesh, before and after the setup of local water institutions. The study was part of a broader project aimed at promoting socially inclusive agricultural intensification. An integrative framework was developed in this study to capture and link the diverse range of factors that influence the distribution of water, including the often-overlooked role of social dynamics and governance arrangements. While interventions around improving water resource infrastructure can be critical for freshwater availability, the case studies show that a breakdown of asymmetric power structures may also be needed for water access to all individuals, especially marginalized groups. Establishing a community-based water institution on its own does not necessarily address power issues in a community. It is imperative that the agency and capacities of the marginalized members are developed and that the institutional arrangements foster an enabling environment for marginalized members to influence decision making. Integrated assessment allowed the case studies to be explored from multiple perspectives so as to gain a greater understanding of the barriers and levers to obtaining equitable outcomes from water interventions.
Identification of Seasonal Sub-Regions of the Drought in the North China Plain
Authors: Cui Yanqiang , Zhang Bo , Huang Hao , Wang Xiaodan , Zeng Jianjun , Jiao Wenhui , Yao Rongpeng
Published: December 2020

Regional climate variability assessment is of great significance in decision-making such as agriculture and water resources system management. The identification of sub-regions with similar drought variability can provide a basis for agricultural disaster reduction planning and water resource distribution. In this research, a modified daily Standardized Precipitation Evapotranspiration Index (SPEI) was used to monitor the spatial and temporal variation characteristics of agricultural drought in the North China Plain from 1960 to 2017, which was studied by using the rotated empirical orthogonal functions (REOF). Through the seasonal REOF process, 7–9 seasonal drought sub-regions are confirmed by applying time series and the correlation relationship of SPEI original data. The strong correlation of these sub-regions indicates that the climate and weather conditions causing the drought are consistent and the drought conditions are independent for the regions that show no correlation. In general, the results of the seasonal trend analysis show that there has been no significant trend value in most areas since 1960. However, it is worth noting that some regions have the positive and negative temporal trends in different seasons. These results illustrate the importance of seasonal analysis, particularly for agro-ecosystems that depend on timely rainfall during different growing seasons. If this trend continues, seasonal drought will become more complex, then a more elaborate water management strategy will be needed to reduce its impact.
Using Field-Based Monitoring to Enhance the Performance of Rainfall Thresholds for Landslide Warning
Authors: Abraham Minu Treesa , Satyam Neelima , Bulzinetti Maria Alexandra , Pradhan Biswajeet , Pham Binh Thai , Segoni Samuele
Published: December 2020

Landslides are natural disasters which can create major setbacks to the socioeconomic of a region. Destructive landslides may happen in a quick time, resulting in severe loss of lives and properties. Landslide Early Warning Systems (LEWS) can reduce the risk associated with landslides by providing enough time for the authorities and the public to take necessary decisions and actions. LEWS are usually based on statistical rainfall thresholds, but this approach is often associated to high false alarms rates. This manuscript discusses the development of an integrated approach, considering both rainfall thresholds and field monitoring data. The method was implemented in Kalimpong, a town in the Darjeeling Himalayas, India. In this work, a decisional algorithm is proposed using rainfall and real-time field monitoring data as inputs. The tilting angles measured using MicroElectroMechanical Systems (MEMS) tilt sensors were used to reduce the false alarms issued by the empirical rainfall thresholds. When critical conditions are exceeded for both components of the systems (rainfall thresholds and tiltmeters), authorities can issue an alert to the public regarding a possible slope failure. This approach was found effective in improving the performance of the conventional rainfall thresholds. We improved the efficiency of the model from 84% (model based solely on rainfall thresholds) to 92% (model with the integration of field monitoring data). This conceptual improvement in the rainfall thresholds enhances the performance of the system significantly and makes it a potential tool that can be used in LEWS for the study area.
A Study on Water and Salt Transport, and Balance Analysis in Sand Dune–Wasteland–Lake Systems of Hetao Oases, Upper Reaches of the Yellow River Basin
Authors: Wang Guoshuai , Shi Haibin , Li Xianyue , Yan Jianwen , Miao Qingfeng , Li Zhen , Akae Takeo
Published: December 2020

Desert oases are important parts of maintaining ecohydrology. However, irrigation water diverted from the Yellow River carries a large amount of salt into the desert oases in the Hetao plain. It is of the utmost importance to determine the characteristics of water and salt transport. Research was carried out in the Hetao plain of Inner Mongolia. Three methods, i.e., water-table fluctuation (WTF), soil hydrodynamics, and solute dynamics, were combined to build a water and salt balance model to reveal the relationship of water and salt transport in sand dune–wasteland–lake systems. Results showed that groundwater level had a typical seasonal-fluctuation pattern, and the groundwater transport direction in the sand dune–wasteland–lake system changed during different periods. During the crop-growth period (5 May–27 October), the average evapotranspiration values of the sand dune, wasteland–sand dune junction, and wasteland were 31–42% of the reference evapotranspiration. The water consumption of sand dune was 1.95 times that of the wasteland–sand dune junction, and 1.88 times that of wasteland. Water loss of the lake was 761.25–869.05 mm (5 May–27 October). The lake is facing the risk of drying up. The vertical salt transport of groundwater at the sand-dune site was 1.13 times that at the wasteland–sand dune junction site, and 1.82 times that at the wasteland site. Of the groundwater salt of the sand dune, 54% was accumulated in the groundwater of the wasteland–sand dune junction. Of the groundwater salt of the wasteland–sand dune junction, 53% was accumulated in wasteland groundwater, and the remaining 47% was accumulated in the lake. Salt storage of the 1 m soil layer of the sand dune was 85% that of the wasteland–sand dune junction, and 82% that of the wasteland. Research results provide a theoretical basis for the ecohydrology of the Hetao plain.
A Pilot Study Combining Ultrafiltration with Ozonation for the Treatment of Secondary Urban Wastewater: Organic Micropollutants, Microbial Load and Biological Effects
Authors: Graça Cátia A. L. , Ribeirinho-Soares Sara , Abreu-Silva Joana , Ramos Inês I. , Ribeiro Ana R. , Castro-Silva Sérgio M. , Segundo Marcela A. , Manaia Célia M. , Nunes Olga C. , Silva Adrián M. T.
Published: December 2020

Ozonation followed by ultrafiltration (O3 + UF) was employed at pilot scale for the treatment of secondary urban wastewater, envisaging its safe reuse for crop irrigation. Chemical contaminants of emerging concern (CECs) and priority substances (PSs), microbial load, estrogenic activity, cell viability and cellular metabolic activity were measured before and immediately after O3 + UF treatment. The microbial load was also evaluated after one-week storage of the treated water to assess potential bacteria regrowth. Among the organic micropollutants detected, only citalopram and isoproturon were not removed below the limit of quantification. The treatment was also effective in the reduction in the bacterial loads considering current legislation in water quality for irrigation (i.e., in terms of enterobacteria and nematode eggs). However, after seven days of storage, total heterotrophs regrew to levels close to the initial, with the concomitant increase in the genes 16S rRNA and intI1. The assessment of biological effects revealed similar water quality before and after treatment, meaning that O3 + UF did not produce detectable toxic by-products. Thus, the findings of this study indicate that the wastewater treated with this technology comply with the water quality standards for irrigation, even when stored up to one week, although improvements must be made to minimise microbial overgrowth.
Hydrochemical Characteristics and Irrigation Suitability Evaluation of Groundwater with Different Degrees of Seawater Intrusion
Authors: Wang Zhenyan , Wang Shu , Liu Wenyue , Su Qiao , Tong Hui , Xu Xingyong , Gao Zongjun , Liu Jiutan
Published: December 2020

Groundwater in coastal aquifers is often affected by seawater intrusion, resulting in water quality deterioration. Using groundwater influenced by seawater intrusion for irrigation can lead to crop failure, erosion of machinery and pipes, and adverse effects on farming. In this study, the results of water testing, methods of statistical analysis, ion ratios, a Piper diagram, and a variety of groundwater irrigation suitability models were used to analyze the chemical composition of groundwater and the influence of seawater intrusion. The result shows that the content of Na+, K+, Ca2+, Mg2+, Cl−, and SO42− in groundwater would increase due to seawater intrusion, and the increasing trend was consistent with the freshwater–seawater mixing line. With the deepening of seawater intrusion, the hydrochemical type gradually changes from Ca-HCO3·Cl to Na·Mg-Cl·SO4 and then to Na-Cl type, and the source of hydrochemical composition changes from “Rock Weathering Dominance” to “Evaporation Dominance”. When the Cl− concentration is greater than 7.1 meq/L, groundwater will corrode pipelines and instruments; when greater than 28.2 meq/L, excessively high salinity of groundwater will have adverse effects on planting; and when greater than 14.1 meq/L, the groundwater hardness is too high, which may make the groundwater unsuitable for cultivation.
Case Study: Reconstruction of Runoff Series of Hydrological Stations in the Nakdong River, Korea
Authors: Kwak Jaewon , Lee Jongso , Jung Jaewon , Kim Hung Soo
Published: December 2020

Reliable runoff series is sine qua non for flood or drought analysis as well as for water resources management and planning. Since observed hydrological measurement such as runoff can sometimes show abnormalities, data quality control is necessary. Generally, the data of adjacent hydrological stations are used. However, difficulties are frequently encountered when runoff series of the adjacent stations have different flow characteristics. For instance, when the correlation between the up- and downstream locations in which the stations are located is used as the main criterion for quality control, difficulties can occur. Therefore, this study aims to suggest a method to reconstruct an abnormal daily runoff series in the Nakdong River, Korea. The variational mode decomposition (VMD) technique is applied to the runoff series of the three target stations: Goryeong County (Goryeong bridge) and Hapcheon County (Yulji bridge and Jeogpo bridge). These runoff series are also divided into several intrinsic mode functions (IMFs) that are governed by basin runoff and disturbed flow caused by the hydraulic structure. The decomposition results based on VMD show that the runoff components in a particular station that is influenced by hydraulic structures could be reconstructed using adjacent stations, but the residual mode could not. The runoff reconstruction model using an artificial neural network (ANN), the two “divided” modes, and the residual component is established and applied to the runoff series for the target station (Yulji bridge in Hapcheon County). The reconstructed series from the model show relatively good results, with R2 = 0.92 and RMSE = 99.3 in the validation year (2019). Abnormal runoff series for 2012 to 2013 at the Yulji bridge station in Hapcheon County are also reconstructed. Using the suggested method, a well-matched result with the observations for the period from 2014 onwards is produced and a reconstructed abnormal series is obtained.
The Effect of Tubificid Bioturbation on Vertical Water Exchange across the Sediment–Water Interface
Authors: Mao Ruichen , Wu Jintao , Qin Xin , Ma Chi , Song Jinxi , Cheng Dandong , Sun Haotian , Li Mingyue
Published: December 2020

The bioturbation activity of macroinvertebrates can affect the level of water exchange across the sediment–water interface. The impact of tubificid worm with different densities on the vertical water exchange at the sediment–water interface was investigated based on laboratory flume experiments. Vertical water fluxes, as well as physiochemical parameters, were measured at seven-day intervals, and the maximum penetration depths were obtained by dye injection before and after the tubificid bioturbation experiment, respectively. The bioturbation effects can be summarized in two aspects: (1) when the density was less than (or equal to) 20 individual/10 cm2, the volume of vertical water exchange positively correlated with the tubificid bioturbation. Once the density exceeded (or equaled) 25 individual/10 cm2, the vertical water flux decreased with increasing tubificid bioturbation. After 14 to 21 days, a negative correlation was identified between the bioturbation and the vertical water flux under all biological densities. (2) The maximum depth that the surface water can penetrate the sediment increased with increasing tubificid density. These results revealed that the vertical water was closely related to the biological density. The study has certain reference significance to understanding the spatiotemporal heterogeneity of hyporheic water exchange on a local scale.
Cost–Benefit Evaluation of Decentralized Greywater Reuse Systems in Rural Public Schools in Chile
Authors: Rodríguez Carolina , Sánchez Rafael , Rebolledo Natalia , Schneider Nicolás , Serrano Jennyfer , Leiva Eduardo
Published: December 2020

Water scarcity is one of the most important climatic threats in recent times. In Chile, the north and north-central areas, with predominantly arid or semi-arid climates, have been strongly affected by the low availability of water, as well as by overexploitation of water resources derived from the negative effect caused by some sectors of the economy such as agriculture and mining. Only 53% of households in rural areas in Chile have access to drinking water from a public network. To date, some pilot greywater treatment systems have been implemented in rural public schools. This paper presents an economic analysis of pilot systems for greywater treatment from three case studies. The results showed that the implementation of these systems would not be economically feasible, since the initial investment costs can exceed USD 5200, which is not offset by the water savings. However, other benefits, such as thermal regulation, better life quality, and the feeling of well-being and satisfaction of students and teachers should be considered to be paramount for the evaluation of treatment systems. In addition, current levels of treated greywater could allow irrigation of 6.24, 5.68, and 3.56 m2/person in the Alejandro Chelén, El Guindo, and Pedro de Valdivia schools, respectively. These results contribute to a better understanding of the social role that should be applied to the evaluation of ecological systems that save water and improve the well-being of the population.
Integrated Aquaculture Recirculation System (IARS) Supported by Solar Energy as a Circular Economy Alternative for Resilient Communities in Arid/Semi-Arid Zones in Southern South America: A Case Study in the Camarones Town
Authors: Cornejo-Ponce Lorena , Vilca-Salinas Patricia , Lienqueo-Aburto Hugo , Arenas María J. , Pepe-Victoriano Renzo , Carpio Edward , Rodríguez Juan
Published: December 2020

In this work, the cultivation of river shrimp was implemented through intensive use of solar radiation for the sustainable development of the Camarones, a village in Chile. An aquaculture production plant was built under water recirculation to produce 8000 k of river shrimp and rainbow trout per year, in a 25:75 ratio, respectively. This was developed taking into account (1) the concept of how to help resilient communities, considering the principles of the circular economy; (2) that the cultivation of these species will use solar water treatment technology to reduce arsenic content present in the natural waters of the Camarones River; and (3) how to add value to the residues obtained from the production plant for better agriculture and to have water to preserve the ecosystem. In addition, this initiative will rely on solar energy and radiation to produce electrical energy and a photochemical reaction to remove arsenic from the water. This work complies with 10 of the 11 principles of the Circular Economy, making it a potential alternative for all areas of the world that have similar characteristics.
Removal of Phenolic Compounds from Olive Mill Wastewater by a Polydimethylsiloxane/oxMWCNTs Porous Nanocomposite
Authors: Turco Antonio , Malitesta Cosimino
Published: December 2020

User-friendly and energy-efficient methods able to work in noncontinuous mode for in situ purification of olive mill wastewater (OMW) are necessary. Herein we determined the potential of oxidized multiwalled carbon nanotubes entrapped in a microporous polymeric matrix of polydimethylsiloxane in the removal and recovery of phenolic compounds (PCs) from OMW. The fabrication of the nanocomposite materials was straightforward and evidenced good adsorption capacity. The adsorption process is influenced by the pH of the OMW. Thermodynamic parameters evidenced the good affinity of the entrapped nanomaterial towards phenols. Furthermore, the kinetics and adsorption isotherms are studied in detail. The presence of oil inside the OMW can speed up the uptake process in batch adsorption experiments with respect to standard aqueous solutions, suggesting a possible use of the nanocomposite for fast processing of OMW directly in the tank where they are stored. Moreover, the prepared nanocomposite is safe and can be easily handled and disposed of, thus avoiding the presence of specialized personnel. After the adsorption process the surface of the nanomaterial can be easily regenerated by mild treatments with diluted acetic acid, thus permitting both the recyclability of the nanomaterial and the recovery of phenolic compounds for a possible use as additives in food and nutraceutical industries and the recovery of OMW for fertirrigation.
Trophic Niches, Trophic Positions, and Niche Overlaps between Non-Native and Native Fish Species in a Subalpine Lake
Authors: Cicala Davide , Polgar Gianluca , Mor Jordi René , Piscia Roberta , Brignone Stefano , Zaupa Silvia , Volta Pietro
Published: December 2020

In the last century, Italian freshwater ecosystems have been invaded by several non-native fish species. In the subalpine Lake Mergozzo (northern Italy), several recently introduced non-native species dramatically expanded their populations. We used carbon and nitrogen stable isotopes to describe the isotopic niches and trophic positions of native and non-native fish species in Lake Mergozzo. We evaluated their trophic niches, trophic diversity, trophic redundancy and trophic evenness utilizing isotopic niche metrics, and estimated asymmetrical niche overlaps. The trophic traits of non-native fish species and Perca fluviatilis clearly define them as trophic generalists, in terms of among-individual variability of their isotopic niches. The historical increase in abundance of fish non-native species in this lake, their dominance by numbers and biomass within the assemblage, and their broad asymmetrical niche overlaps suggest that their higher degree of trophic generalism might have been one of the key factors that have promoted the invasion of the recipient community.
Genome-Resolved Metagenomics and Antibiotic Resistance Genes Analysis in Reclaimed Water Distribution Systems
Authors: Wang Changzhi , Hong Pei-Ying
Published: December 2020

Water reuse is increasingly pursued to alleviate global water scarcity. However, the wastewater treatment process does not achieve full removal of biological contaminants from wastewater, hence microorganisms and their genetic elements can be disseminated into the reclaimed water distribution systems (RWDS). In this study, reclaimed water samples are investigated via metagenomics to assess their bacterial diversity, metagenome-assembled genomes (MAGs) and antibiotic resistance genes (ARGs) at both point of entry (POE) and point of use (POU) in 3 RWDS. The number of shared bacterial orders identified by metagenome was higher at the POE than POU among the three sites, indicating that specific conditions in RWDS can cause further differentiation in the microbial communities at the end of the distribution system. Two bacterial orders, namely Rhizobiales and Sphingomonadales, had high replication rates in two of the examined RWDS (i.e., site A and B), and were present in higher relative abundance in POU than at POE. In addition, MAG and ARG relative abundance exhibited a strong correlation (R2 = 0.58) in POU, indicating that bacteria present in POU may have a high incidence of ARG. Specifically, resistance genes associated with efflux pump mechanisms (e.g., adeF and qacH) increased in its relative abundance from POU to POE at two of the RWDS (i.e., site A and B). When correlated with the water quality data that suggests a significantly lower dissolved organic carbon (DOC) concentration at site D than the other two RWDS, the metagenomic data suggest that low DOC is needed to maintain the biological stability of reclaimed water along the distribution network.
The Main Drivers to Face the Challenges of Increasing the Intelligence of Sanitary Sewage Systems in Brazilian Cities
Authors: de Alcantara Raphael G. , de Alcantara Midiã C. P. G. , Chinelli Christine K. , Dias Fabricio C. , Mariano Renata L. V. , Longo Orlando C. , Soares Carlos A. P.
Published: December 2020

The sewage system is one of the components of the complex ecosystem of cities. Although increasing the intelligence of this system is an essential driver for having smarter cities, there are few works aimed at identifying drivers that enhance the intelligence of urban sanitary sewage systems. The identification of these drivers, as well as the degree of importance of each one, is strongly influenced by the perception of researchers and professionals about the reality of each country. In this work, we identified the main drivers that increase the intelligence of the Brazilian urban sanitary sewage systems based on extensive and detailed bibliographic research and in the vision of 241 Brazilian professionals with experience in the concerned field. We used factor analysis to explore the relationship between the drivers. The survey results showed that the twenty drivers found in the literature can be grouped into six factors, depending on their approach, and that seven were considered priorities. They also showed that the path to be followed to increase the intelligence of sewage systems in Brazilian cities is still influenced by the challenges of solving structural problems.
Impacts of Climate on Renewable Groundwater Resources and/or Stream–Aquifer Interactions
Authors: Alcalá Francisco , Pulido-Velazquez David , Ribeiro Luis
Published: December 2020

The evaluation of aquifer recharge is essential to make a quantitative evaluation of renewable groundwater resources required to implement proper water policies aimed at maintaining stream–aquifer interactions, guaranteeing water supply to human activities, and preserving groundwater-dependent ecosystems at different spatial and temporal scales and climate conditions [...]
Sustainability and Metabolic Revolution in the Works of Henri Lefebvre
Authors: Napoletano Brian M. , Clark Brett , Foster John Bellamy , Urquijo Pedro S.
Published: December 2020

Humanity’s present social–ecological metabolic configuration is not sustainable, and the need for a radical transformation of society to address its metabolic rifts with the rest of nature is increasingly apparent. The work of French Marxist Henri Lefebvre, one of the few thinkers to recognize the significance of Karl Marx’s theory of metabolic rift prior to its rediscovery at the end of the twentieth century, offers valuable insight into contemporary issues of sustainability. His concepts of the urban revolution, autogestion, the critique of everyday life, and total (or metabolic) revolution all relate directly to the key concerns of sustainability. Lefebvre’s work embodies a vision of radical social–ecological transformation aimed at sustainable human development, in which the human metabolic interchange with the rest of nature is to be placed under substantively rational and cooperative control by all its members, enriching everyday life. Other critical aspects of Lefebvre’s work, such as his famous concept of the production of space, his temporal rhythmanalysis, and his notion of the right to the city, all point to the existence of an open-ended research program directed at the core issues of sustainability in the twenty-first century.
O acordo de delação premiada e o limite de atuação do poder judiciário
Authors: Brüggemann Felipe
Published: December 2020

O presente artigo tem por objetivo verificar a concepção do instituto da delação premiada no ordenamento jurídico brasileiro, realizando um apanhado da evolução legislativa até o momento atual. No decorrer do trabalho, busca-se dirimir algumas discussões doutrinárias e jurisprudenciais, em especial, quanto ao limite de atuação do juiz na homologação e na análise do acordo de delação.
LIFE LIMIT TRENDS BY THE EXAMPLE OF FOREIGN CARS
Authors:   Russian State Agrarian University, MITYAGIN G.E.
Published: December 2020

Modern studies on the impact of road transport on air pollution indicate a steady increase in negative impact, reflected in an annual increase in emissions. In 2017, they reached the level of 14.5 million tons, which exceeds the level of 2012 by 14 %, while despite the tightening of re-quirements for cars, an increase of 2.5 % was recorded only in the last year [1]. Modern cars do not cause significant harm to the environment, unlike earlier ones, however, the share of relatively new cars is small, about 15 % of the fleet [2]. Positive results in terms of reducing gross emissions of harmful substances, especially in cities, can be achieved by reducing or modernizing the fleet of vehicles owned by both legal entities and individual owners. Weighted and socially responsible decisions in the field of modernization of the fleet of vehicles of individual owners can be made on-ly after a detailed analysis of not only the age structure of the fleet, but also the trends in the limit of service life, as an indicator of the owner’s willingness to voluntarily stop using the car.
MANAGEMENT OF TRANSPORTATION AND PRODUCTION PROCESSES UNDER THE CONDITIONS OF UNPLANNED REDISTRIBUTION OF RESOURCES
Authors:   Voronezh State Forestry Engineering University, SHTEPA A.A. , BELOKUROV V.P. ,   Voronezh State Forestry Engineering University, GORBUNOV V.G. ,   Voronezh State Technical University
Published: December 2020

Presents an algorithm and a mathematical model for controlling a technological process to minimize losses associated with an emergency in production. The conditions and features of the functioning of the technological process in the conditions of the flow method of performing work are presented. The conditions and schemes of pairing interconnected resources have been deter-mined, which allow their replacement to improve the efficiency of technological process control while observing the technology or organization of construction. Criteria are enclosed that assess the quality of the organisational-economic situation before and after the management of the tech-nological process of management. A matrix of incidents is given, which makes it possible to deter-mine the conditions of an emergency situation, to assess the loss and to make an operative decision about the compensation of these losses, which have arisen during an emergency stop of the pro-cess. The proposed model allows you to vary the parameters, change the search area to achieve the desired results. The model is invariant to the object of technological process control, which allows changing its parameters by adjusting the adjacency and incident matrices.
EMPLOYMENT OF GRADUATES OF SECONDARY VOCATIONAL EDUCATION IN INFORMATION TECHNOLOGIES AND INFORMATION SECURITY: CAREER PREFERENCES AND JOB SEARCH
Authors:   All-Russia Research Institute of Labour, Moscow, Russia, Voloshina I.A. , Kozlova L.V. ,   All-Russia Research Institute of Labour, Moscow, Russia
Published: December 2020

The article presents the study results of job search tactics and career preferences of graduates in the field of information technology and information security (hereinafter referred to as IT specialties) who graduated from educational institutions of secondary vocational education (hereinafter referred to as SVE) in 2016–2019. The main method to collect data was a formalized quantitative survey of 1,500 graduates, including those living in regional centers (cities with a population of over one million) in 17 constituent entities of the Russian Federation, by means of a structured online questionnaire. The respondents took part in the study by filling out the questionnaire online, by telephone and in person filling out a printed copy of the questionnaire. To improve the quality of the data and to form a holistic view of the peculiarities of recruiting graduates of secondary vocational education in IT specialties, the questionnaire survey was supplemented by 15 profound interviews on a structured guide with representatives of professional educational organizations who deal with the employment of graduates. The study results may help determine the main employment practices and career guidelines for young IT specialists (channels and duration of job search, demand for professional competencies, salary expectations, etc.), identify the main reasons why young specialists refuse to work by profession, develop conceptual schemes, and key directions for their employment.