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17661. 题目: Composting organic waste from the broiler production chain: A perspective for the circular economy
文章编号: N21112110
期刊: Journal of Cleaner Production
作者: Maico Chiarelotto, Juan Camilo Pires Salcedo Restrepo, Higor Eisten Francisconi Lorin, Felippe Martins Damaceno
更新时间: 2021-11-21
摘要: The broiler production chain (BPC) has associated environmental impacts, costs, and effects that are not compensated by the Brazilian socioeconomy. The objective of this review was to discuss BPC waste composting from a circular economy perspective. Organic solid waste is a negative externality and the agroindustry must contribute to its internalization, especially in countries with significant production, consumption, and export of chicken meat. The BPC has four main stages of significant organic waste production: reproductive poultry, hatchery, broiler growth, and broiler industry. The principal residues of this industry are reproductive poultry litter, hatchery waste, feed waste, carcasses, truck cleaning solid fraction, flotation sludge, sausage casings, charcoal, and ash. These residues have varying characteristics, such as total organic carbon (TOC) from ranging 4.4–56.22% and nitrogen from 0.2 to 9.33%. It is evident that raw materials, nutrients, and energy are misused throughout the BPC; developing countries especially cannot sustain the loss of these valuable resources. Composting has emerged as a method for mitigating the impacts of BPC waste, however, there are some obstacles. The high nitrogen concentration in BPC residues make balancing the C/N ratio complex. This deficit carbon demands residues from other sectors, such as from tree pruning, cotton residues, raw glycerin, and Napier grass. The produced BPC compost has favorable attributes to be reincorporated into the supply chain as an agricultural input. However, little research has been conducted on the short, medium, and long-term impacts of BPC compost application on different crop and soil types. Cultivations close to BPC facilities which grow broiler feed components (e.g., corn) are attractive for a closed cycle strategy and for approaching the principles of the circular economy.

17662. 题目: Understanding how inland lake system environmental gradients on the Qinghai–Tibet Plateau impact the geographical patterns of carbon and water sources or sink
文章编号: N21112109
期刊: Journal of Hydrology
作者: Yao Lu, Yang Gao, Jennifer A.J. Dungait, Junjie Jia, Kun Sun, Shuoyue Wang, Yafeng Wang, Zhaoxi Li
更新时间: 2021-11-21
摘要: On the Qinghai–Tibet Plateau (QTP), salinity, area, and altitude are the three main environmental gradients, and they are also likely to be the main influencing factors of lake water and carbon (C) sources. We collected water samples from lake and river systems on the QTP to determine their associative physical, chemical, biological, and isotopic indicators. Firstly, the ionic composition of individual lake systems on the QTP varied significantly, and evaporation was the main controlling factor respective to most of their chemical characteristics. Secondly, glacial meltwater (8%), rainwater (26%), soil water (28%), and the evaporation effect (38%) were the main controlling factors of lake water on the QTP. Atmospheric exchange (72%), soil organic matter (SOM) (1%), and rock weathering (19%) were the main dissolved inorganic carbon (DIC) sources of lake water on the QTP. Thirdly, salinity and altitude were the main influencing factors of lake water and C sources, especially salinity. Findings from this study are intended to supplement the knowledge base on C and water coupling effects in plateau lake systems while also improving our understanding on the response of inland lake systems to climate change globally.

17663. 题目: Changes in the characteristics of organic matter associated with hydrodynamics and phytoplankton size structure in the central-eastern Yellow Sea
文章编号: N21112108
期刊: Science of The Total Environment
作者: Yeonjung Lee, Dong Han Choi, Howon Lee, Myung Jin Hyun, Giyeong Kim, Haeun Lee, Wonseok Yang, Jihoon Kim, Jongseok Won, Kongtae Ra, Hyeryeong Jeong, Jin Young Choi, Seok Lee, Moonkoo Kim, Jae-Hoon Noh
更新时间: 2021-11-21
摘要: The central-eastern Yellow Sea is an important region for transporting organic matter (OM) to the Pacific Ocean, however, there is limited information available regarding the characteristics and sources of OM in this area. The present study investigated the concentrations and stable isotopic compositions of carbon (δ13C) and nitrogen (δ15N) for particulate matter and sediment in the central-eastern Yellow Sea during April 2019. The physicochemical properties (i.e., salinity, temperature, fluorescence, and nutrients), size-fractionated phytoplankton biomass (Chl-a), and concentration and fluorescence characteristics of dissolved organic matter (DOM) were also determined. The satellite SST and Chl-a data indicated that mixing cold and warm water masses were observed. Phytoplankton blooms occurred a few days before our sampling campaign. Considering the high concentration of suspended solids in the bottom layer, resuspended sediment caused by tidal currents could be a major source of OM in coastal areas. The δ13C values of particulate organic matter (POM) in the coastal area were higher (−22 to −23‰) than those of OM from terrestrial sources (approximately −27 to −28‰). Instead, the lowest δ13C values were observed in the central part of our study area, where the relative abundance of picophytoplankton was high. These results indicated that phytoplankton-derived OM after phytoplankton spring blooms in the coastal area could be the primary source of OM rather than terrestrial origins. In addition, the source of OM that presented low δ13C values could be picophytoplankton-derived OM. The characteristics of DOM were related to biological processes (mediated by phytoplankton and bacteria) and resuspension of sedimentary organic matter. We did not detect an influx of large amounts of terrestrial OM in coastal sediments. Overall, the source and characteristics of OM appeared to be influenced by the hydrodynamics and the distribution properties of lower trophic-level organisms in the central-eastern Yellow Sea during the spring season.

17664. 题目: Distribution and dynamics of dissolved organic matter in the Changjiang Estuary and adjacent sea
文章编号: N21112107
期刊: Journal of Geophysical Research: Biogeosciences
作者: Jinqiang Guo, Shengkang Liang, Xinke Wang, Xiaoju Pan
更新时间: 2021-11-21
摘要: Large, river-dominated estuaries provide important land-ocean interfaces for biogenic element fluxes that impact global marine biogeochemistry. However, the reactivity and fate of dissolved organic matter (DOM) in this dynamic region remain not well understood. In this study, three cruises were conducted in February, May and July 2017 in the Changjiang Estuary and adjacent sea (CEAS). Incubation experiments to determine photochemically and/or biologically mediated degradation of terrigenous and marine DOM were performed. Dissolved organic carbon (DOC), chromophoric DOM (CDOM) absorption and total dissolved amino acids (TDAA) were measured. DOM photodegradation and transformation were indicated by the CDOM spectral slope (S275−295) and diagenetic state by DOC-normalized yields of TDAA [TDAA (%DOC)]. From the river to the open sea, DOC showed non-conservative mixing and was rapidly removed in low salinity areas. Photodegradation, biodegradation and photoenhanced biodegradation are important DOC removal mechanisms and exhibit specific responses depending on DOC source and composition. Terrigenous DOM is vulnerable to photodegradation, while marine DOM experiences rapid biodegradation. Contrary to DOC, TDAA (%DOC) increased from the river to the near-shore and then decreased toward the open sea, indicating the contribution of fresh marine plankton production. A box model showed that the annual DOC removal of CEAS was 2.6 ± 1.9 × 106 tons. Seaward increase of ammonium (NH4-N) was observed in the CEAS; photoammonification, biomineralization of autochthonous and allochthonous DOM are potential NH4-N regeneration mechanisms. A model was developed to calculate surface DOC concentrations based on CDOM absorption coefficients allowing high resolution monitoring of DOC in the CEAS.

17665. 题目: Non-chemical biofouling mitigation systems for seawater cooling tower using granular activated carbon biofiltration and ultrafiltration
文章编号: N21112106
期刊: Journal of Environmental Chemical Engineering
作者: Al-Bloushi Mohammed, Arun Kumar S. Raju, Jieun Lee, Yumin Oh, Sanghyun Jeong
更新时间: 2021-11-21
摘要: Biofouling is a serious problem in industrial cooling tower. It damages equipment through bio-corrosion, causes blockages, and increases energy consumption by decreased heat transfer. One of the most popular methods used in the cooling tower process to control the biofouling is disinfection by chlorination. However, chlorination forms harmful disinfection byproducts in the presence of organic. The research aims to remove the nutrients and microorganisms from seawater for biofouling mitigation in seawater cooling towers (SCTs) without chemical usage. Granular activated carbon (GAC) biofiltration and ultrafiltration (UF) membrane pretreatment systems were employed to reduce the amount of nutrients and the number of microorganisms in seawater entering the main process, respectively. Assimilable organic carbon (AOC) levels in the feed seawater are directly linked with a bacterial growth, thus it can be used as an indicator of biofouling potential after pretreatment. GAC biofilter exhibited a high efficiency in the reducing of biofouling potential by removing AOC in seawater feed. UF could minimize the initial microbial growth. Further, a hybrid GAC/UF system achieved the removal of DOC up to 78% with enhanced AOC reduction (less than 60% compared to value without pretreatment). It indicates that the GAC/UF hybrid is a promising process minimizing the chemical usage and mitigating the biofouling growth. This study can provide the useful information to operator of SCTs to manage the biofouling problems without chemical and to operate it environmentally-friendly.

17666. 题目: Arbuscular mycorrhizal fungi reverse selenium stress in Zea mays seedlings by improving plant and soil characteristics
文章编号: N21112105
期刊: Ecotoxicology and Environmental Safety
作者: Chenyu Sun, Yisen Yang, Muhammad Zeeshan, Shengfeng Qin, Junqing Ma, Lu Liu, Juan Yang, Xunbo Zhou, Jinghua Huang
更新时间: 2021-11-21
摘要: Selenium (Se) is a beneficial trace element for certain animals including humans, while remaining controversial for plants. High Se concentration in soil is toxic to plants especially at seedling stage of the plants. Although, arbuscular mycorrhizal fungi (AMF) are important for plant stress resistance; but the mechanisms by which AMF alleviate Se stress in crop seedlings are unclear. Therefore, we investigated the potential strategies of AMF symbiosis to alleviate Se stress in maize (Zea mays) from plants and soil perspectives. Results showed that Se stress (Se application level > 5 mg kg−1) significantly inhibited leaf area, shoot dry weight, and root dry weight of maize (P < 0.05). In contrast, AM symbiosis significantly improved root morphology, increased nitrogen and phosphorus nutrition, promoted shoot growth, inhibited the transport of Se from soil/roots to shoots, and then diluted the concentration of Se in shoots (32.65–52.80%). In general, the response of maize growth to AMF was mainly observed in shoots rather than roots. In addition, AMF inoculation significantly increased the easily extractable glomalin-related soil protein and organic matter contents and decreased the availability of soil Se to the plant. Principal component analysis showed that AMF promoted growth and nutrition uptake of maize was the most dominant effect of Se stress alleviation, followed by the decrease of soil Se availability, limiting Se transport from soil/roots to shoots. Moreover, the expression of Se uptake-related ion transporter genes (ZmPht2, ZmNIP2;1, and ZmSultr1;3) in maize roots were down-regulated upon AM symbiosis which resultantly inhibited the uptake and transport of Se from soil to maize roots. Thus, AMF could impede Se stress in maize seedlings by improving plant and soil characteristics.

17667. 题目: Biologically Enhanced Coagulation–Ultrafiltration Process for Healthy Water Production with Low Fouling Propensity
文章编号: N21112104
期刊: ACS ES&T Engineering
作者: Lei Xu, Shuo Li, Nigel J. D. Graham, Wenzheng Yu
更新时间: 2021-11-21
摘要: Coagulation combined with ultrafiltration (UF) is an effective drinking water treatment process. However, inefficient removal of natural organic matter (NOM) and membrane fouling problems, especially those initiated by the adhesion of biopolymers, greatly restrict the practical application of the UF process. Here, we investigated a biologically enhanced coagulation–ultrafiltration (CUF) process treating samples of a natural surface water, which demonstrated a superior NOM removal and antifouling performance. The membrane flux (under 1.0 bar constant pressure) of the biologically enhanced CUF [using polyaluminum chloride (PACl)] process scheme was approximately 4.4 and 8.4 times higher than that of a conventional CUF and direct UF process, respectively, and PACl was found to perform better than AlCl3. Characterization of the NOM showed that the biological pretreatment combined with the coagulation process significantly contributed to the reduction of hydrophobicity, aromaticity, and molecular weight of the dissolved organics. Analyses of biopolymers showed that the combined process can remove over 99% of the biopolymers (represented by proteins and polysaccharides), which are considered to be the main cause of membrane fouling. Results of X-ray photoelectron spectroscopy and FTIR analyses further elucidated the transformation and reduction of biopolymers during the combined process. With respect to the disinfection byproduct formation potential (DBP-FP), the results showed that the conventional CUF process had a limited impact on the DBP-FP, while the biologically enhanced CUF process had a substantial impact consistent with meeting the current EPA DBP standards. Overall, this study has highlighted the potential advantages of using a biologically enhanced CUF process for producing higher quality drinking water with a simultaneous low membrane fouling propensity.

17668. 题目: Treatment of Metal Cutting Wastewaters in Bipolar Trickle Tower Reactor by Electrocoagulation and Electrochemical-Fenton methods: Reduction of Organic Matter, Boron, Heavy Metals, and Toxicity with Sludge Characterization
文章编号: N21112103
期刊: Water, Air, & Soil Pollution
作者: Tuğçe Gedik, Fadime Karaer Özmen, Filiz Bayrakcı Karel, Ali Savaş Koparal
更新时间: 2021-11-21
摘要: The metal cutting wastewater was treated with electrocoagulation (EC) and electrochemical-Fenton (EF) method in a bipolar trickle tower reactor. In EC treatment, the COD removal efficiency was obtained as 81.3% with 89.0 kWh/m3 energy consumption using 0.7 mA/cm2 current density and 0.2 mM Na2SO4. With the EF method, 99.2% COD removal was achieved with 78.0 kWh/m3 energy consumption in optimum conditions (0.7 mA/cm2 current density, 90 mM H2O2, 0.2 mM Na2SO4 at pH 3) after 30-min treatment of wastewater. In EC and EF process, TOC and toxicity of the wastewater were decreased during the treatment period in parallel with COD removal as a result of response surface methodology (RSM) optimization. It was observed that the main metal and heavy metal contents were B, Al, Cr, Zn, Ni, Cu, Cd, and Pb when their concentrations were listed in descending order at the level of µg/L, and these heavy metal and boron contents were removed more efficiently in the EC process than EF treatment. The FTIR-ATR spectrum of the sludge observed the strong peaks around 875 cm−1 and 884 cm−1 related to vibrations of the Fe–O bonds in iron oxide after the EC and EF treatment. This study showed that metal cutting wastewater was successfully treated with EC and EF first time in the literature even if it had high COD, TOC, toxicity, and heavy metal contents.

17669. 题目: Nitrogen-Doped Biochar as Peroxymonosulfate Activator to Degrade 2,4-dichlorophenol: Preparation, Properties and Structure–Activity Relationship
文章编号: N21112102
期刊: Journal of Hazardous Materials
作者: Yang Jingjing, Wang Jinling, Li Hong, Deng Yurong, Yang Chen, Zhao Qing, Dang Zhi
更新时间: 2021-11-21
摘要: Nitrogen-doped biochar (NCMs) has shown great potential as metal-free catalysts for persulfates. To understand the evolution law of properties of NCMs with preparation conditions, eleven NCMs were prepared and characterized by EA, BET, Raman, XPS, and conductivity. Surface area and conductivity can be improved by higher pyrolysis temperature and longer retention time. Distribution of nitrogen species of NCMs was greatly influenced by pyrolysis temperature. Subsequently, these NCMs were applied to activate peroxymonosulfate to degrade 2,4-dichlorophenol. A linear correlation of the initial apparent degradation rate constant (kobs) of 2,4-dichlorophenol with conductivity and ratio of graphitic N was newly established, revealing that conductivity and graphitic N of NCMs would be the key property deciding degradation efficiency of 2,4-dichlorophenol. Positive effect of conductivity can be ascribed to the mediated electron-transfer mechanism. Electron-transfer mechanism is also proved by quenching experiments and solvent deuterium isotope effect experiment. Graphitic N would be the main active site for PMS activation. Understanding the evolvement rule of properties of NCMs with preparation conditions combined with the correlations between reactivity and properties of NCMs is meaningful for preparation of nitrogen-doped biochar as well as the development of carbonaceous materials with high performance in persulfates-based advanced oxidation processes.

17670. 题目: Cunninghamia lanceolata and understory ferns had positive rhizosphere effects on the temperature sensitivity of soil microbial respiration in a subtropical forest
文章编号: N21112101
期刊: Geoderma
作者: Xuechao Zhao, Peng Tian, Shengen Liu, Zhaolin Sun, Zhangquan Zeng, Qingkui Wang
更新时间: 2021-11-21
摘要: Rhizosphere processes play a critical role in soil organic carbon (SOC) cycling that is primarily regulated by temperature. Understanding the response of rhizospheric SOC decomposition to global warming, which is called temperature sensitivity (Q10), is pivotal for predicting the feedback of SOC cycling to global warming. However, the rhizosphere effects (REs) on Q10 and their underlying mechanisms in forest ecosystems remain unclear. Here, the REs on Q10 for Cunninghamia lanceolata and three understory ferns (e.g., Woodwardia japonica, Parathelypteris glanduligera and Microlepia marginata) in a subtropical forest were explored using a novel incubation procedure with periodically changing temperatures based on the mean annual temperature. Our results showed that the positive REs on Q10 were observed for all plant species, which ranged from 33% to 88%, and P. glanduligera exhibited higher REs on Q10 than C. lanceolata. The positive REs on Q10 were associated with the rhizospheric nitrogen (N) availability and microbial properties. The REs on N component (i.e., the REs on total N, NH4+ and NO3− along the first PCA axis), which is the most important driver, had a positive direct effect on the REs on Q10. Furthermore, the rhizospheric microbial biomass and the REs on microbial residues were also positively related to the REs on Q10. Overall, these findings highlight that plant-covered soils have high risks of C emissions under planetary warming, underscore the importance of root-soil interactions for accurately predicting SOC dynamics and reveal that rhizospheric nutrients and microbial properties drive the feedback of the root-associated SOC cycle to global warming.

17671. 题目: Occurrence and stability of organic intercalation in clay minerals from permafrost-affected soils in the High Arctic – A case study from Spitsbergen (Svalbard)
文章编号: N21112009
期刊: Geoderma
作者: Wojciech Szymański, Marek Drewnik, Mateusz Stolarczyk, Łukasz Musielok, Magdalena Gus-Stolarczyk, Michał Skiba
更新时间: 2021-11-20
摘要: Climate warming is responsible for many environmental changes in the Arctic, which lead to the decomposition of soil organic matter (SOM) and emissions of greenhouse gases from the soil into the atmosphere. Soil minerals play a crucial role in SOM stabilization. However, little is known about the occurrence and stability of organo-mineral associations in permafrost-affected soils in the Arctic. The main aims of this study were: 1) to determine the potential occurrence of SOM within interlayers of swelling clay minerals in the permafrost-affected soils in central part of Spitsbergen (Svalbard, High Arctic) and 2) to determine resistance of the intercalated SOM within the clay minerals against thermal and chemical oxidation. The obtained results indicate that 10% to 15% of organic carbon and 30% to 45% of total nitrogen occurring in the clay fraction of the Arctic permafrost-affected soils are intercalated within the swelling clay minerals. We also report that this part of SOM is highly resistant to both chemical and thermal oxidation. These findings should be taken into consideration in the refinement of climate models and in studies concerning the thawing of permafrost, SOM mineralization, and emissions of greenhouse gases from the soil into the atmosphere.

17672. 题目: Techno-economic analysis reveals the untapped potential of wood biochar
文章编号: N21112008
期刊: Chemosphere
作者: Josef Maroušek, Lukáš Trakal
更新时间: 2021-11-20
摘要: The United Nations estimates the rate of deforestation over 10 million hectares per year, with additional infested wood available due to drought, bark beetle calamity and other damage vectors. Processing the hard-to-reach infested wood into biochar via mobile pyrolysis units seems to be a good option for fire prevention. However, since most biochar is currently produced mainly from biological waste, there is not enough experience with wood biochar on a large scale. Review of current knowledge, followed by techno-economic assessment reveals that following the chemical composition of the feedstock, wood biochar outperforms other types of biochar in terms of high porosity. Therefore, wood biochar shows excellent results in increasing the amount of plant-available water content in soil and appears to be an excellent tool for recycling nutrients (especially into plant-available forms of phosphorus and nitrogen). The overall positive effects of biochar application change from abiotic to biotic over time because as it decays, many of its physical properties disappear, but it can boost soil microbial communities on which soil fertility depends. As global climate change creates a wide range of factors that damage forest cover, wood biochar consequently represents untapped potential in the field of soil, nutrient, and energy management.

17673. 题目: Contrasting effects of biochar- and organic fertilizer-amendment on community compositions of nitrifiers and denitrifiers in a wheat-maize rotation system
文章编号: N21112007
期刊: Applied Soil Ecology
作者: Yulong Shi, Xingren Liu, Qingwen Zhang, Yingchun Li
更新时间: 2021-11-20
摘要: This research investigated the N2O fluxes and community compositions of nitrifiers and denitrifiers in a winter wheat-summer maize rotation system on the North China Plain. The experiment included three treatments: 1) a control treatment (CK); 2) biochar at 10.0 t ha–1 yr−1 (C); and 3) organic fertilizer at 7.5 t ha−1 yr−1 (M). The application of biochar reduced the cumulative N2O emissions by 47.7% and 62.2% in the maize and wheat seasons, respectively, compared with those of the CK treatment. Organic fertilizer increased the cumulative N2O emissions by 311.1% in the maize season and had no significant effects on them in the wheat season. Organic fertilizer reduced the cumulative N2O emissions by 39.8% in the nonfertilizer period of the maize season. The cumulative N2O emissions in the maize season accounted for 75.2–90.0% of the annual emissions among all the treatments. Biochar and organic fertilizer affected soil N2O emissions mainly by changing soil denitrifiers. In the maize season, the lower abundances of Candidatus Nitrosoarchaeum (AOA-amoA), Nitrosomonas (AOB-amoA), Mesorhizobium (nirK), Magnetospirillum (nirS) and Halomonas (nirS) may result in lower N2O emissions in the biochar treatment, and organic fertilizer had a similar influencing mechanism on N2O emissions during the nonbasic fertilizer and nontopdressing periods of the maize season. In the wheat season, the dominant genus Alicycliphilus (nosZ) was the major contributor to decreasing N2O emissions in the biochar treatment, while there was no biomarker related to N2O emissions in the M treatment. The soil pH, NO3−-N content and water-filled pore space (WFPS) were the key factors shifting the community compositions of nitrifiers and denitrifiers in this study. The application of biochar could be a better practice to improve saline-alkali soil with lower N2O emissions. These findings will improve our understanding of the nitrifiers and denitrifiers response to biochar and organic fertilizer.

17674. 题目: Fate and Transport of Cyanotoxins and Natural Organic Matter through Virgin and Reactivated Granular Activated Carbons
文章编号: N21112006
期刊: ACS ES&T Water
作者: Bingran Chen, Ying Hong, Maria Meyer, Kevin Reynolds, Yoontaek Oh, Hyunsik Kim, Heejong Son, Pyung-Kyu Park, John J. Lenhart, Soryong Chae
更新时间: 2021-11-20
摘要: Cyanotoxins, including microcystins (MCs) and cylindrospermopsin (CYN), are potent hepatotoxins produced during cyanobacterial algal blooms. Understanding how readily these compounds are removed by granular activated carbon (GAC) is important for protecting aquatic ecosystem and public health. Since GAC is often reused after reactivation, the potential exists for reactivated carbon to exhibit performance deterioration after numerous reactivations. This study compared the removal of cyanotoxins with virgin and reactivated GAC using rapid small-scale column tests (RSSCTs) using three model cyanotoxins (i.e., MC-LR, MC-RR, and CYN) at two different concentrations (i.e., 10 and 40 μg/L) spiked into conventionally treated Ohio River water from a local treatment facility. Among the three tested toxin variants, MC-LR and MC-RR did not show breakthrough during 16 RSSCT run days (or 28,800 bed volume), even with reactivated GAC columns at spiked concentrations of 40 μg/L. CYN shows the weakest adsorption, as suggested by its earlier breakthrough in reactivated GAC at approximately 16 RSSCT days. These results imply that water treatment utilities should consider a finite number of reactivation cycles of GAC because GAC pores could be widened during thermal reactivation, ultimately reducing the removal efficiency of more hydrophilic cyanotoxin variants in the presence of natural organic matter.

17675. 题目: Ameliorating soil structure for the reservoir riparian: The influences of land use and dam-triggered flooding on soil aggregates
文章编号: N21112005
期刊: Soil and Tillage Research
作者: Kai Zhu, Yiguo Ran, Maohua Ma, Wenjuan Li, Yaseen Mir, Jiaojiao Ran, Shengjun Wu, Ping Huang
更新时间: 2021-11-20
摘要: Soil aggregates are considered to be strongly influenced by land use and hydrological regime. Yet, the relative importance of land use and flooding intensity on soil aggregate stability (SAS) in riparian zones remains unclear. Hence, the objective of this study was to examine the effects of land use and flooding intensity on SAS, as well as the aggregate-associated organic carbon (C) and nitrogen (N) contents in the riparian zone along the Three Gorges Reservoir of Yangtze River, China. In 2019, during the reservoir discharge period when the reservoir is at the lowest water level, SAS and aggregate-associated organic C and N contents were investigated along a gradient of the flooding intensity across riparian zones with different restoration practices, including natural grasslands, artificial mixed forests consisting of flood tolerant plants (mulberry and metasequoia), and transplanted lotus. Croplands (i.e., corn, paddy and peanut fields) at different elevations above sea level were used as references. The results showed that artificial mixed forests were more effective in improving the SAS than natural grasslands at elevations above 173 m, while natural grasslands were more effective in improving the SAS than artificial mixed forests and lotus at elevations below 173 m. However, riparian soil stability cannot be simply explained by land use management only, but rather the coupling effects of land uses and flooding intensity. Variation partitioning analysis showed that dam-triggered flooding intensity (21.5%) contributed more than land use (15.5%) in explaining riparian SAS. Also, the soil organic carbon (SOC) and total nitrogen (TN) had significantly positive correlations with the proportion of large macroaggregates (>2 mm) and SAS, indicating that maintaining higher levels of SOC and TN via the development of land use strategies commensurate with the flooding intensity was conducive to the formation and stability of soil aggregates. Meanwhile, the relative contribution of microaggregates (<0.053 mm) to bulk SOC or N content decreased with elevation. Therefore, the finding provides new insights into the focus of C sequestration, and suggests that C assessment should be shifted to microaggregates in the riparian zone. Overall, our study highlights that different land use strategies should be conducted for different elevations to promote SAS, aggregate-associated C and N accumulation in the riparian zone, which can provide a reference for ecological restoration in areas experiencing similar conditions.

17676. 题目: Activation of Biochars by Waste Phosphoric Acids: An Integrated Disposal Route of Waste Acids and Solid Waste
文章编号: N21112004
期刊: ACS Sustainable Chemistry & Engineering
作者: Hongyun Niu, Huiwen Jin, Qing Sun, Yali Shi, Xiaole Zhang, Yaqi Cai
更新时间: 2021-11-20
摘要: Waste phosphoric acid can pose severe adverse effects to environments and ecological systems if directly discharged. As an important and irreplaceable element, the recovery of phosphorus (P) is essential for the sustainability of modern world. To recover P from waste acids, we impregnated coffee ground or chicken manure into waste phosphoric acid polishing solution to store H3PO4 in biomass. After activated/carbonized at high temperature and subsequent washing with purified water, H3PO4 was recollected and activated carbon (AC) was achieved. The results indicated that the coffee ground was ideal reagents to recover P, and the recovery of H3PO4 was as high as 70% when the carbonization temperature was 500–600 °C, and the obtained AC was of the characteristic of the P dopant, large surfaces (315–811 m2/g), and mesopores. However, chicken manure led to little loss of P at high temperatures by converting P2O5/H3PO4 into metaphosphate salts. This novel strategy realizes efficient utilization of solid waste, P recovery, heavy metal separation, and organic chemical elimination from waste acids, without producing new solid or liquid waste.

17677. 题目: Biochar in the 21st century: A data-driven visualization of collaboration, frontier identification, and future trend
文章编号: N21112003
期刊: Science of The Total Environment
作者: Fanzhi Qin, Jialing Li, Chen Zhang, Guangming Zeng, Danlian Huang, Xiaofei Tan, Deyu Qin, Hao Tan
更新时间: 2021-11-20
摘要: The massive amounts of publication data are highly valuable, because in addition to the advancement in science, technology, and policy, such data can provide critical information and guidance on what have been published, what topical changes have evolved, and what are the trending fields deserving more attention. In the 21st century, biochar has played an indispensable role in the long-term global development strategies in response to “Carbon neutralization”, “Agricultural management”, and “Environmental restoration”, and accumulated many high-quality publications. Herein, this study provides a new data-driven bibliometric analysis strategy and framework for mining the core content of massive literature data, and aims at bringing unique insights for the research prospects as well as opportunities of biochar. The results show that biochar researches have made great progress from 1999 to 2020, but cross-disciplinary teamwork should be further emphasized. The research frontier identification reveals that sewage treatment, efficient removal, and functional composite materials will be the issues which must be paid continual attention at present and in the future. Furthermore, studies on global climate impact, biomass resource utilization, carbon sequestration, carbon cycle, and even the negative effects of biochar have gradually begun to be taken seriously.

17678. 题目: Microbial influences on tufa deposition in a tropical climate
文章编号: N21112002
期刊: Sedimentary Geology
作者: Fumito Shiraishi, Yusaku Hanzawa, Jiro Asada, Leonardo Fadel Cury, Anelize Manuela Bahniuk
更新时间: 2021-11-20
摘要: Tufas are freshwater carbonate deposits that attracted attention as paleoclimatic archives and analogs of microbial carbonates. Recent geomicrobiological studies revealed that cyanobacterial photosynthesis significantly contributed to the precipitation of CaCO3 (photosynthesis-induced CaCO3 precipitation; PICP), and that the chemical properties of extracellular polymeric substances (EPS) secreted by cyanobacteria significantly influenced on the depositional fabrics. These depositional processes were revealed from tufas formed in cool and temperate climates; however, their applicability to tufa deposits in other climate conditions remains unclear. This study, therefore, investigated tufa deposits that formed in a tropical climate in Brazil and applied geomicrobiological techniques, including microelectrode measurements and lectin-binding analysis, to clarify their depositional processes. The surfaces of eight investigated tufa samples were dominated by cyanobacteria. Microelectrode measurements indicated the occurrence of PICP in all the samples. However, five samples additionally exhibited a Ca2+ concentration decrease at the tufa surface, even in dark conditions, which was difficult to explain by abiotic CaCO3 precipitation and light-independent microbial metabolisms. Based on the fluxes calculated from the results of microelectrode measurements, the contribution of PICP to the formation of CaCO3 precipitates was estimated as 100% for three samples, similar to tufa deposits in cool and temperate climates. For the remaining five deposits, the average contributions of PICP, Ca2+ adsorption to organic matter, and other processes were estimated as 36%, 3%, and 61%, respectively. Among the phototrophs living the tufa surface, Phormidium and Leptolyngbya secreted EPS abundantly containing carboxyl groups, and were heavily calcified. In contrast, Phormidesmis, Calothrix, Pleurocapsa, and diatoms secreted EPS without detectable amount of carboxyl groups, and they were largely not calcified and formed pore spaces. Such influence of microbial EPS on the depositional fabrics were common to cool and temperate tufas. Nonetheless, some features would be specific to tropical tufas, including the contribution of unidentified light-independent processes, conical and columnar surface morphologies, and unclear annual lamination.

17679. 题目: From Adsorption to Precipitation of U(VI): What is the Role of pH and Natural Organic Matter?
文章编号: N21112001
期刊: Environmental Science & Technology
作者: Carmen A. Velasco, Adrian J. Brearley, Jorge Gonzalez-Estrella, Abdul-Mehdi S. Ali, María Isabel Meza, Stephen E. Cabaniss, Bruce M. Thomson, Tori Z. Forbes, Juan S. Lezama Pacheco, José M. Cerrato
更新时间: 2021-11-20
摘要: We investigated interfacial reactions of U(VI) in the presence of Suwannee River natural organic matter (NOM) at acidic and neutral pH. Laboratory batch experiments show that the adsorption and precipitation of U(VI) in the presence of NOM occur at pH 2 and pH 4, while the aqueous complexation of U by dissolved organic matter is favored at pH 7, preventing its precipitation. Spectroscopic analyses indicate that U(VI) is mainly adsorbed to the particulate organic matter at pH 4. However, U(VI)-bearing ultrafine to nanocrystalline solids were identified at pH 4 by electron microscopy. This study shows the promotion of U(VI) precipitation by NOM at low pH which may be relevant to the formation of mineralized deposits, radioactive waste repositories, wetlands, and other U- and organic-rich environmental systems.

17680. 题目: Mainstream nitrogen removal in membrane aerated biofilm reactor at minimal lumen pressure
文章编号: N21111915
期刊: Science of The Total Environment
作者: Rongfen Chen, Yan Zhou
更新时间: 2021-11-19
摘要: Nitrogen removal via anammox is a promising and sustainable solution in mainstream wastewater treatment. To maintain stable anammox process, competitors of anammox bacteria should be suppressed while cooperators need to be favoured. This study demonstrated a synchronous aerobic and anaerobic ammonium removal process in a membrane aerated biofilm reactor (MABR) under minimal lumen pressure. By adjusting the lumen pressure, aerobic and anaerobic ammonium oxidation rate can be synchronized to minimize interference of nitrite oxidizing bacteria (NOB) by limiting NOB's access to both oxygen and nitrite. Long-term performance indicated that PN/A in MABR could be achieved at zero positive aeration pressure. Furthermore, by connecting two MABRs in series, high total nitrogen (TN) removal efficiency of 71.1% ± 5.3% was attained with a TN removal rate of 30.1 ± 3.2 mg-N/L/d. The organic carbon present in the wastewater reduced the nitrate concentration in the effluent while not affecting the overall nitrogen removal efficiency and rate. Real-time qPCR analysis suggested that the abundance of amoA gene was relatively stable while K-strategist Nitrospira 16S rRNA gene did not surge in the long-term operation. High throughput sequencing showed that Candidatus Brocadia and uncultured anaerobic ammonium oxidizing bacteria from Chloroflexi were the most abundant anammox taxa. Denitrifiers, such as Denitratisoma may be responsible to reduce the nitrate in the effluent.