 Subjects -> WATER RESOURCES (Total: 160 journals)
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- Acknowledgement of Reviewers for 2022
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PubDate: 2023-03-15
- Using Multiple Geophysical Methods to Refine a Stratigraphic Conceptual
Site Model at a Nuclear Waste Site-
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Abstract: Abstract At contaminated sites, there is a critical reliance on conceptual site models of which a key component is the geologic framework model (GFM), which is used to build predictive fate and transport modeling in support of remediation goals. We detail an ongoing study at a nuclear waste site (Hanford Site, Washington, USA) where surface geophysical methods were used to complement existing borehole information and to help site new boreholes to update and refine the GFM. Ground-based electrical resistivity tomography (ERT), time-domain electromagnetics (TEM), and seismic data was acquired on the Hanford Site’s Central Plateau, where the presence of a hydraulically transmissive subsurface feature, or paleochannel, was suspected but uncertain based on contaminant concentrations at sparsely located boreholes. To assess and compare ERT, TEM, and seismic geophysical datasets, co-located data was acquired in an area where the existing GFM was more certain. Surrounding the suspected paleochannel, ERT and seismic refraction tomography showed similar subsurface structures consistent with a channelized feature. While TEM interpretation was limited in the suspected paleochannel area due to a thick resistive top layer and high electromagnetic noise, TEM showed greater utility in a different area where these factors were less prevalent. Based on the results of quasi-3D ERT inversions, we propose updates to the GFM, including identifying a paleochannel. Further, we evaluate the utility of geophysical methods and examine lessons learned that will be used as a basis for continued characterization efforts to support site management decisions and implementation efforts.
PubDate: 2023-03-09
- Saponite-inspired Materials as Remediation Technologies for Water
Treatment: an Overview-
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Abstract: Abstract Saponite, a clay mineral from the smectite group, has distinctive characteristics and properties that allow structural modifications to expand its potential to remove hazardous contaminants in aqueous media. We conducted a systematic study on the use of saponite in photocatalytic and adsorption processes for water treatment. The Scopus, Web of Science, and SciELO databases were used to find scientific publications. Several methods for modifying saponite have been described. Titanium dioxide is the most widely used in photocatalysis. In adsorption, saponite derivatives are very efficient materials for treating water and wastewater. They are applied mainly to remove heavy metals, surfactants, hydrocarbons, caffeine, toxic metabolites, and dyes. Therefore, saponite is a clay mineral that could be better exploited in environmental applications, as it has promising properties for effectively removing organic and inorganic pollutants. 
PubDate: 2023-03-07
- Assessment of Climate Change Impact on Water Balance of Lake Hawassa
Catchment-
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Abstract: Abstract In this study, we assessed the impact of climate change (CC) on the water balance of the Lake Hawassa catchment (a sub-catchment of the Rift Valley basin) in southern Ethiopia. The CMhyd (Climate model data for hydrologic modeling) was used to correct biases in the Representative Concentration Pathway (RCP) scenarios under the Hadley Global Environment Model 2-Earth System (HadGEM2-ES) for the 2050s (2041–2070) and 2080s (2071–2100). The CC impact analysis performed by the Soil and Water Assessment Tool (SWAT) demonstrated very reliable performance during the calibration (NSE = 0.81, R2 = 0.61) and validation (NSE = 0.85, R2 = 0.88) periods. Projected precipitation (PPT) is expected to increase by 3.4% and 6.9% in the 2050s, and reduce by 1.5% and 0.2% in the 2080s, respectively for the RCP4.5 and RCP8.5, while, respectively, minimum and maximum temperatures (Tmin and Tmax) are expected to increase by 0.6 °C and 3.2 °C under RCP4.5 and by 1.6 °C and 3.8 °C under RCP8.5. By the end of 2100, the long-term water balance of Lake Hawassa catchment under RCP4.5 and RCP8.5 showed PPT increased by 7.1% and reduced by 11.6%, surface runoff increased by 8.8% and reduced by 16.2%, lateral discharge reduced by 40.5% and 49.8%, water yield reduced by 19% and 39.4%, evapotranspiration increased by 21.1% and 19.2%, and potential evapotranspiration increased by 76.1% and 76.7% respectively. These results indicate that the water balance of the catchment will be altered by CC. Therefore, constantly monitored and updated sustainable water resource management and development is required.
PubDate: 2023-02-24
- Eco-Friendly Enhancement of Secondary Effluent Characteristics with Air
and Oxygen Nanobubbles Generated by Ceramic Membrane Filters-
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Abstract: Abstract Nanobubbles (NBs) have potential properties, are environmentally friendly, and are sustainable to be used in a variety of applications: industries, agriculture, medical technology, and engineering applications such as water/wastewater treatment. This paper focuses on improving the characteristics of municipal secondary effluent (SE) utilizing oxygen bubbles (OBs), conventional coarse air bubbles (ABs), oxygen nanobubbles (ONBs), and air nanobubbles (ANBs). NBs were generated by injecting pressured gases through a tubular ceramic membrane with nanopores. Several tests have been used to determine the quality of tested SE before and after different injection times, including dissolved oxygen concentration (DO), pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total dissolved solids (TDS), total suspended solids (TSS), sulfide, orthophosphate, organic nitrogen, ammonia, oil and grease, and Escherichia coli (E. coli). The results show the priority of ONBs in the enhancement of SE quality. For example, after injecting ONBs, OBs, ANBs, and ABs in SE, the TSS was reduced by 57%, 42%, 28% and 14%, the COD by 62%, 41%, 26% and 12%, the BOD5 by 73%, 56%, 43% and 21%, and the organic nitrogen decreased by 19%, 11% and increased by 14% and 9%, respectively. These findings are intended to grasp the gaps in our understanding of how NBs affect the advanced treatment of SE.
PubDate: 2023-02-23
- Enhanced Toxic Dye Degradation Using Single Crystal Zn-doped Fe3O4
Octahedrons-
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Abstract: In the present work, single crystalline octahedral Zn-doped Fe3O4 was prepared through a simple hydrothermal method and then analyzed. The possible mechanism for the formation of Zn-doped Fe3O4 octahedrons is discussed. Their photo-Fenton activity in photodegradation of Rhodamine B under visible light was sequentially investigated. The physicochemical properties of prepared ferrites were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The analysis of the results showed that synthesized products are uniform Zn-doped Fe3O4 octahedrons with high crystallinity. The experimental results manifested that Ostwald ripening processes and N2H4∙H2O amount plays an important role in the formation of the octahedrons. Also, octahedral Zn-doped Fe3O4 exhibited high photocatalytic capacity for dye degradation. Highlights • Zn-doped Fe3O4 octahedral-shaped were prepared by solvothermal method. • Ostwald ripening and N2H4.H2O play the important role in the formation of octahedral photocatalyst. • The catalysts exhibit high photo-Fenton activity. • Rhodamine degradation showed no significant change during four successive cycles.
PubDate: 2023-02-22
- Conforming to Agricultural Water Reuse Criteria: Wastewater Recovery by
Electrooxidation Integrated with Nanofiltration/Reverse Osmosis-
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Abstract: Abstract In this study, two membrane configurations were investigated for water recovery in order to determine the potential for quality irrigation water production from alkaloid industry wastewater. In the first configuration, electrooxidation (EO) was used as a pretreatment before the NF90/BW30 units. In the second configuration, a single-pass, two-stage system consisting of NF4 and NF90/BW30 membranes was applied by replacing the EO unit with NF4. The initial and final fluxes in the single-pass two-stage system with NF4 and NF90 were calculated as 10.2 Lm− 2h− 1 and 5.4 Lm− 2h− 1, respectively. Initial fluxes for the NF4 + BW30 and EO + BW30 combinations were 9.4 Lm− 2h− 1 and 3.2 Lm− 2h− 1, respectively. Increasing the current density from 256 to 768 A/m2 caused the specific energy consumption (SEC) to increase from 10.26 to 15.84 kWh/kg COD. Scanning Electron Microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used for membrane autopsies. Compliance with the criteria for agricultural reuse of recovered water was evaluated based on four key parameters: salinity, pathogens, nutrients, and heavy metals. The combination of electrooxidation and membrane treatments enabled simultaneous disinfection, reduction of salinity and heavy metals to comparable agricultural water reuse criteria.
PubDate: 2023-02-21
- Growth, Yield and Water Productivity of Tomato as Influenced by Deficit
Irrigation Water Management-
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Abstract: Abstract The deficit irrigation offers water savings potential that is becoming popular in arid and semi-arid regions reducing freshwater use over time. A two-year factorial experiment was conducted to evaluate growth, yield and water productivity of tomato under water deficit irrigation of the drip and furrow method. The experiment was carried out in a split-plot design with drip irrigation and furrow irrigation as main plot treatments, and soil moisture regimes (0, -10, -20, -30 kPa) as subplots. Data were collected on growth parameters, physiological traits, yield and water productivity of tomato. The results showed that physiological traits, yield, and water productivity were significantly influenced by irrigation system and soil moisture regime. The drip irrigation system with -10 kPa soil moisture regime reduced total water input by 22.6% and 19.8% and gave 28% and 22% higher fruit yields in 2020 and 2021, respectively, compared with furrow irrigation system. Plant growth was higher and flowering occurred earlier (3 days) with drip irrigation system than with furrow irrigation. When the soil water content was -10 kPa, drip irrigation performed significantly better than for other soil moisture regimes by improving physiological and phenological attributes, and thereby, advancing tomato growth and fruit yield. Thus, a drip irrigation system with soil moisture regime -10 kPa could reduce total water input through precise irrigation, maximizing tomato yield and water productivity.
PubDate: 2023-02-17
- Velocity Field of Submerged Multiple Non-buoyant Jet Groups in Crossflow
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Abstract: Abstract This paper presents the results of a laboratory study on the three-dimensional velocity field of circular non-buoyant multiple jets discharged into a perpendicular crossflow. Two to four momentum jets were taken in a group with spacings five times the jet diameters and the three-dimensional velocity field was measured using an Acoustic Doppler Velocimetry (ADV) system to investigate the interaction of jets with crossflow. The rear jets were found to be less deflected than the front one due to the reduction of effective crossflow velocity because of the sheltering effect as well as the entrainment demand. For a jet spacing of 5 times of jet diameter, the effective crossflow to upstream approach velocity ratios were found to vary between 0.4 and 0.6 regardless of the momentum length scale and the number of jets in a group. The rates of velocity reduction in between jets observed in this study, were favorably compared with previous results, where velocity was inferred from Laser Induced Fluorescence (LIF) measurements. The findings of this study can be used to predict the jet trajectories and dilutions of multiple jets in crossflow as well as modeling of discharges from multiport diffusers. This work will be helpful for the engineers and other scientists dealing with the disposal of wastewater, thermal effluents, or air pollutants into flowing environments.
PubDate: 2023-02-16
- Application of Machine Learning and Remote Sensing for Gap-filling Daily
Precipitation Data of a Sparsely Gauged Basin in East Africa-
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Abstract: Abstract Access to spatiotemporal distribution of precipitation is needed in many hydrological applications. However, gauges often have spatiotemporal gaps. To mitigate this, we considered three main approaches: (i) using remotely sensing and reanalysis precipitation products; (ii) machine learning-based approaches; and (iii) a gap-filling software explicitly developed for filling the gaps of daily precipitation records. This study evaluated all approaches over a sparsely gauged basin in East Africa. Among the examined precipitation products, PERSIANN-CDR outperformed other satellite products in terms of root mean squared error (7.3 mm), and correlation coefficient (0.46) while having a large bias (50%) compared to the available in situ precipitation records. PERSIANN-CDR also demonstrates the highest skill in distinguishing rainy and non-rainy days. On the other hand, Random Forest outperformed all other approaches (including PERSIANN-CDR) with the least relative bias (-2%), root mean squared error (6.9 mm), and highest correlation coefficient (0.53).
PubDate: 2023-02-13
- Analysis of Weather Radar Datasets through the Implementation of a Gridded
Rainfall-Runoff Model-
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Abstract: Abstract This study develops a methodological framework to analyze raw weather radar datasets of fine temporal and spatial scale by implementing them into rainfall-runoff simulations. Since there is uncertainty in radar datasets, this study focuses on the error margins that can be produced in the discharge when various radar reflectivities (Z) are applied in rainfall rate (R) relationships. A gridded rainfall-runoff model is devised based on the time-area diagram method to be applicable in ungauged basins. The study area chosen is the rural part of the Sarantapotamos basin, located in west Attica, Greece, which is the largest subbasin within the observation area of the National Technical University (NTUA) X-Band weather radar. Five Z-R relationships are used to simulate a total of six convective and stratiform events. The results highlight the correlation of the Z-R relationship to the storm type, indicating that a proper Z-R relationship should be used in each case. Specifically, it is found that convective events are more sensitive to the Z-R relationship used than the respective stratiform ones. A stratiform-based relationship tends to increase rainfall volume, while a convective-based relationship tends to decrease it. Furthermore, it is shown that using an inappropriate Z-R in a convective event might lead to unrealistic values, whereas in a stratiform event, its impact can be negligible. Since the discharge is what determines whether any flood Early Warning System (EWS) issues the appropriate warnings, these results are deemed important for the correct assimilation of weather radar datasets.
PubDate: 2023-02-11
- Dissipation of Penoxsulam in Paddy Soil, Water and Plants, and
Quantification of its Residues and its Residual Toxicity to Fish-
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Abstract: Abstract The aim of this field study was to evaluate residues and dissipation behaviours of penoxsulam herbicide in the soil, water and rice plants, and assess its relative toxicity to fish for two consecutive years 2014 and 2015. Penoxsulam residues were analysed by HPLC–DAD in the soil, water fish and rice plant samples collected from 0.2 days till harvest after its spraying in the paddy field. Fish were sampled from the adjoining ponds at 30, 60, 90 and 100 days to analyse penoxsulam residues as well as residual toxicity. The limit of determination was found to be 0.003 and 0.001 µg/g for soil and water, and 0.01 µg/g for rice grain, straw and fish samples. The results showed that penoxsulam dissipated in the soil of rice field and adjoining pond water at rapid to moderate rate. The degradation half-life of penoxsulam in the soil was found to be 7.32 and 10.4 days. At harvest, 0.010 µg/g residues of penoxsulam were detected in paddy straw, whereas below 0.015 µg/g residues were found in the rice grains. Runoff from the rice fields resulted in penoxsulam residues in the adjacent pond water. At 30 days, toxicity to fish was observed due to presence of penoxsulam residues in the pond water. However, no fish mortality was observed in the pond water at 90 and 100 days. Based on dissipation half-life and penoxsulam residues in soil, a waiting period of 87 days is recommended. It can be concluded that due to moderate half-life of penoxsulam in the paddy soil, its spraying may be considered as safe for weed control in the paddy fields, and the suspected risk through consumption of rice sprayed with penoxsulam is negligible. However, due to its leaching potential and lateral movement, adverse effects on fish is expected. Overall, this study demonstrates a better understanding of the use of penoxsulam for sustainable weed management in the paddy fields and resulting residues in the soil, water and plants, and possible adverse effects of its residues on fish in the two-year period.
PubDate: 2023-02-06
- Dynamic Linkages between Environmental Factors and Carbon Emissions in
Thailand-
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Abstract: Thailand is a tourist destination country experiencing continuous economic growth, rapid urbanization, industrialization, and agricultural production, which is causing higher energy consumption and carbon dioxide (CO2) emissions. This study aims to investigate the dynamic effects of economic growth, renewable energy use, urbanization, industrialization, tourism, agricultural productivity, and forest area on CO2 emissions in Thailand. The Autoregressive Distributed Lag (ARDL) bounds testing approach and the Dynamic Ordinary Least Squares (DOLS) methodology were used to analyze time series data from 1990 to 2020. According to the estimates, a 1% rise in economic growth, urbanization, industrialization, and tourism will raise CO2 emissions by 0.97%, 0.17%, 0.06%, and 0.05%, respectively. Furthermore, a 1% increase in renewable energy use, agricultural productivity, and forest area may result in reductions in CO2 emissions of 0.71%, 0.22%, and 0.69%, respectively. This article makes policy recommendations on low-carbon economies, renewable energy use, sustainable urbanization, green industrialization, eco-friendly tourism, climate-smart agriculture, and sustainable forest management, all of which could help ensure environmental sustainability by lowering emissions. Furthermore, the findings of the study may guide other developing nations seeking to implement effective environmental sustainability approaches while also increasing climate change mitigation and adaptation measures. Highlights • This study investigated the nexus between environmental factors and carbon emissions. • Dynamic Ordinary Least Squares method has been applied by utilizing time series data. • Carbon emissions rise with economic growth, urbanization, industry, and tourism. • Renewable energy, agriculture, and forests showed emission reduction potential. • This article recommends sustainable development and emission reduction policies.
PubDate: 2023-01-31
- Chlorine Removal from Water by Biochar Derived from Various Food Waste
Natural Materials-
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Abstract: Abstract The aim of this paper was to investigate the effectiveness of pyrolyzed low-cost food waste natural materials from the food industry on the removal of chlorine from water. Biochar was produced after pyrolysis at 850 oC from malt spent rootlets (MSR), walnut shells, and apricot, olive, carob and grape kernels. The biochars were characterized for their surface area, microporosity, functional groups and pH. Continuous flow column experiments were conducted at varying flow rates to evaluate the efficiency of biochars to remove free and total chlorine. The initial free and total chlorine concentrations in water fed to the columns were 2.0 and 2.2 mg/L, respectively. The chlorine removal of free and total chlorine of all materials tested ranged from 76 to 92% and 80 to 95%, respectively, with the MSR exhibiting the highest removal. MSR biochar was subjected to the highest cumulative water volume passed through the column (162 L/g) and exhibited the highest total chlorine removal capacity (6 to 330 mg/g). Olive kernel also reached high chlorine removal (99%), while apricot kernel, grape kernel, carob seed and pulp presented poor chlorine removals.
PubDate: 2022-12-31
DOI: 10.1007/s40710-022-00617-4
- Pathogens in Runoff Water Treated by a Sustainable Urban Drainage System
in a Developing Country-
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Abstract: Abstract Sustainable Urban Drainage Systems (SUDS) are commonly used to control flooding in urban areas. These structures store and treat stormwater runoff. Several studies in high-income countries have reported the presence of pathogens in runoff water, but it is expected that runoff water in developing countries contains higher pathogen concentrations given their lack of resources to properly manage sewage; this could result in higher risks of infection for people interacting with SUDS. In this study, we investigated pathogen concentrations (i.e., Salmonella spp. and E. Coli O157) at the micropool of a SUDS train composed of a grassed swale followed by a dry extended detention basin in Bogotá (Colombia) during a 25-week period. We also estimated the risk of infection with the analyzed pathogens, given the high level of exposure to the detention structure. Additionally, we investigated if any of the physicochemical or meteorological variables were associated with pathogen concentrations at the site. We found that pathogen concentrations greatly exceeded concentrations reported for stormwater runoff in developed countries, namely 1562 CFU/mL, on average, for Salmonella spp. and 9160 CFU/mL, on average, for E. Coli O157. The risk of infection from Salmonella spp. and E. Coli O157 greatly exceeded risks previously reported for recreational waters and SUDS. Pathogen concentrations were associated with precipitation and the concentration of suspended solids in the runoff. Given our findings, it is recommended that SUDS in developing countries should consider potential higher pathogen concentrations in stormwater runoff to reduce exposure.
PubDate: 2022-12-17
DOI: 10.1007/s40710-022-00610-x
- Impact of Confinement on the Reduction of Pollution and Particulate Matter
Concentrations. Reflections for Public Transport Policies-
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Abstract: Abstract Different initiatives have been implemented to improve air quality in large cities, such as encouraging travel by sustainable modes of transport, promoting electro-mobility, or the car-free day. However, to date, we have not found statistics that indicate to what extent the concentration levels of particulate matter PM2.5, PM10 and nitrogen oxides (NOx) pollutants decrease as a result of public policy. We used official data from the Chilean Government’s national air quality information system (SINCA) for the Santiago metropolitan region and estimated the impact of the confinement by COVID-19 on the ambient concentration average values of NOx gases and particulate matter PM2.5 and PM10, which are the main air pollutants produced by the transport sector after CO2. We found that in general there are significant differences between the average levels of gas emissions for 2020 compared to 2019. In particular, we found that, for the months of total confinement May-July, the monthly average levels decreased between 7% and 19% for particulate matter PM2.5, between 18% and 50% for PM10 and between 34% and 48% for NOx. With the return to the new normality, these improvements in ambient concentration levels may be affected by the increase in private transport trips, due to the reluctance of citizens to return to mass public transport. Our results, therefore, represent the maximum impact that can be expected in reducing ambient concentration levels in the city of Santiago of Chile when a mobility reduction of gasoline vehicles is implemented.
PubDate: 2022-12-17
DOI: 10.1007/s40710-022-00611-w
- Heterogeneous Photocatalytic Degradation of Nevirapine in Wastewater Using
the UV/TiO2/H2O2 Process-
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Abstract: Abstract This work sought to study the elimination of nevirapine (NVP) from synthetic wastewater using the UV/TiO2/H2O2 system. The main objectives were to evaluate the influence of operating parameters, reaction kinetics, contributing reactive species, degradation pathway, and catalyst reusability. The research surface methodology (RSM) was utilized for optimizing process variables. Five process variables (pH, NVP concentration, TiO2 dosage, H2O2 concentration, and irradiation time) were optimized with the responses set as NVP and Total organic carbon (TOC) removals (%), respectively. 89.23% NVP and 85.71% TOC removals were achieved after 60 min of irradiation under optimum conditions. All the experimental factors were significant for NVP removal. pH was the most dominant factor, with the highest removals obtained under acidic conditions (pH 3). NVP removal conformed to the pseudo-first-order model with a rate constant (k1) of 0.03676 min− 1. Increasing pH reduced the rate constant by 75.38%, while there was an increase of 43.55% with H2O2. NVP degradation was primarily driven by the •OH and h+VB. The photocatalyst demonstrated good stability against NVP loss over four cycles. Although the UV/TiO2/H2O2 process has shown promising results in removing pharmaceuticals and dyes in wastewater, its application for the degradation of ARVs remains limited. As far as the authors know, the UV/TiO2/H2O2 process and RSM have not yet been reported for the degradation and optimization of NVP in wastewater, respectively. The findings of this work illustrate that the UV/TiO2/H2O2 system, applied with RSM optimization, can effectively degrade and mineralize NVP in wastewater.
PubDate: 2022-12-16
DOI: 10.1007/s40710-022-00615-6
- Role of Porous and Non-Porous Draft Tube in Photocatalytic Degradation of
Toluene in Spouted Bed Reactors-
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Abstract: Abstract This paper aims to examine the effect of the porous and non-porous draft tube on the photocatalytic degradation of toluene in the spouted bed reactor. For this purpose, titanium dioxide nanoparticles were used as photocatalysts, and UV lamps as radiation sources. Degradation efficiency and CO2 selectivity were compared. By-products were also detected in three spouted bed reactors with and without a porous and non-porous draft tube. The results revealed that the degradation efficiency of toluene in the spouted bed reactor without a draft tube was 30.75%. The insertion of porous and non-porous draft tubes in the spouted bed reactor increased the degradation efficiency to 54.88% and 47.63%, respectively. Meantime, CO2 selectivity decreased from 100 to 50.8% within 180 min irradiation time in the spouted bed reactor without draft tube, while in the spouted bed reactors with porous and non-porous draft tubes it was maintained at 89.85% and 84.35%, respectively. No by-products were detected in the spouted bed reactors with porous and non-porous draft tubes. However, the formation of benzaldehyde and benzoic acid in the spouted bed reactor without a draft tube revealed that the mineralization of toluene had not been completed in this reactor. This study demonstrated that the insertion of a draft tube in spouted bed reactors provides an appropriate contact between the toluene, photocatalyst and UV, and prevents the deactivation of the photocatalyst.
PubDate: 2022-12-11
DOI: 10.1007/s40710-022-00612-9
- Inhibition Kinetics of Volatile Fatty Acid-rich Leachate on Substrate
Utilization and Electricity Generation in an Earthen Microbial Fuel Cell-
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Abstract: Abstract Volatile fatty acid-rich (VFA) leachate obtained from kitchen waste was treated in an earthen microbial fuel cell (EMFC) to generate electricity. Leachate with various chemical oxygen demand (COD) concentrations was fed to the EMFC at a constant hydraulic retention time of 12 h, resulting in varying organic loading rates (OLR, 2–7 kg COD/m3·d). The highest organic matter removal was 74.5% at an OLR of 2 kg COD/m3·d. Whereas, the highest power and current densities of 0.76 W/m3 and 7.94 A/m2 were obtained at an OLR of 7 kg COD/m3·d, respectively. The experimental data illustrated that the performance started reducing once it reached an influent COD concentration of 3.0 g/L, which may be due to the substrate inhibition phenomenon. This behavior affected the substrate utilization rate (SUR) and power production from the EMFC and can be modeled with the help of kinetic models. Among the models studied, the Han-Levenspiel model predicted SUR and power density with a correlation coefficient of 0.947 and 0.953, respectively. For SUR, the kinetic parameters rmax, Ks and Sm were 5.56 kg COD/m3·d, 4.00 kg/m3 and 18.55 kg/m3, respectively. For power density, the parameter Pmax, Ks and Sm were, respectively, 0.97 W/m3, 6.21 kg/m3 and 11.0 kg/m3. The current generation followed a Nernst-Monod model with an R2 value of 0.945. The kinetic parameter Jmax, Ks and η were 8.81 A/m2, 1.42 kg/m3 and 0.192, respectively. The results demonstrate the capability of EMFC to treat leachate and predict response for the treatment of the complex substrates.
PubDate: 2022-12-06
DOI: 10.1007/s40710-022-00614-7
- Impacts of Pb-Induced Oxidative Stress on Morphological, Physiological and
Biochemical Properties of Tree Species-
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Abstract: The aim is to analyze the Pb-tolerance of three commonly found tree species and determine the Pb-toxicity and impacts of Pb on growth, physiological and biochemical parameters. In the present study, we examine the response of Pb-induced stress in three commonly growing tree species i.e., Terminalia arjuna, Cassia fistula, and Pongamia pinnata based on various characteristics at an interval of 90 days for 360 days. Plant seedlings were exposed to 0 (control), 200, 450, and 600 mg of Pb/kg dry soil. Our results showed that Pb significantly reduced growth, photosynthetic pigments, and physiological parameters in all studied species. These reductions were highest in P. pinnata followed by C. fistula, and T. arjuna. Besides, Pb-induced toxicity caused many fold rise in biochemicals such as malondialdehyde, proline, phenolics, thiols, and others. These elevations were highest in T. arjuna followed by C. fistula and P. pinnata. Further, it was also observed that with an increase in the number of days of year (DOY) of Pb exposure, plants showed a reduction in physiological parameters but an increase in growth and biochemical parameters in all studied species. Furthermore, the physiological parameters showed a negative and the biochemical parameters showed a positive correlation with both DOY and treatments, while the growth parameters showed a negative correlation with treatments and a positive correlation with DOY. Hence, we can conclude that the three selected species are promising candidates to be recommended for plantation in Pb-polluted urban areas due to their Pb-tolerance. Overall, the study provides a better understanding of the impacts of Pb on tree species in the long-term and in assessing their potential for sustainable plantations in urban areas. Highlights • Pb reduced growth, and affected physiology and biochemistry in all studied species. • P. pinnata was most affected followed by C. fistula and T. arjuna. • Physiology was diminished with the number of days of Pb exposure and treatments. • Physiology had negative and biochemistry had positive correlation with Pb exposure. • Growth was decreased due to Pb exposure but increased with number of days.
PubDate: 2022-12-05
DOI: 10.1007/s40710-022-00616-5
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