1. 题目: Disentangling the effects of OM quality and soil texture on microbially mediated structure formation in artificial model soils
作者: Franziska B. Bucka, Vincent J.M.N.L. Felde, Stephan Peth, Ingrid Kögel-Knabner
摘要: The interaction between mineral particles and soil organic matter (SOM) is an important and complex process during soil structure formation, in which the effects of soil texture and OM properties are intertwined. Within the SOM, there are residues of particulate organic matter (POM) of various sizes, as well as microbial necromass co-existing. These OM residues undergo microbial decay whose products stabilize particle connections and thus induce aggregate formation. We developed an experimental set-up to study early soil structure formation within a controlled lab environment. Artificial soil microcosms with a mineral mixture of different textures (clay loam, loam, and sandy loam) were used to perform a short-term incubation for 30 days under constant water tension. OM was added individually either as POM of two different size classes (milled hay litter, 0.63–2 mm and <63 µm, respectively) or bacterial necromass (Bacillus subtilis). The dry mixing process and incubation of the mineral mixtures led to particle–particle interactions and fine particle coatings of the sand grains as shown by a reduction in the specific surface area (N2-BET). The OM residues were quickly accessed and degraded by microbes (peak in CO2-release within the first 10 days of incubation), which induced the formation of water-stable aggregates. The POM of both sizes induced predominantly the formation of macroaggregates (0.63–30 mm) with a mass contribution of 72% to 91%, irrespective of the mixtures’ texture. The bacterial necromass induced a texture-dependent formation of macro- and microaggregates (63–200 µm), with larger aggregates in sand-rich mixtures. The different aggregate sizes were related to differences in the developed microbial community, as obtained by PLFA analysis. The bacterial necromass induced a microbial community dominated by bacteria, whereas the POM fostered a high relative abundance of fungi, whose hyphae could enmesh and stabilize large aggregates in all textures. The formed aggregates are water-stable but have a very low mechanical stability. Dry crushing with a mechanical loading frame revealed that very low forces (<4 N) were sufficient for breaking the aggregates down. Microbial growth and degradation of the OM residues led to OM patches occupying <17% of the mineral surfaces after the incubation, suggesting that the aggregates are loosely connected structures, bound together by some distinct spots of processed OM acting as gluing joints. This initially formed scaffold holds particles in place for further stabilization processes and resists immersion in water but exhibits no stability toward mechanical forces.
2. 题目: A critical review on the application and recent developments of post-modified biochar in supercapacitors
期刊: Journal of Cleaner Production
作者: Xiangping Li, Jianguang Zhang, Bin Liu, Zhenping Su
摘要: The demand for sustainable and renewable energy sources has gained tremendous research attention around the world over the past years. Supercapacitor, among lots of energy storage devices, has been attracted many researches for the advantages of high power density, fast charge-discharge capability and cycle stability. Compared with other carbon materials, biochar materials have attracted special attention as efficient, low-cost, active materials for energy storage. In this work, the typical preparation and modification methods of biochar as the supercapacitor electrode are classified. the factors influencing the electrochemical performance of biochar, such as specific surface area (SSA), pore structure, surface chemical modification and conductivity are systematically discussed. This work studied the relationship between carbon with mesopore and hierarchical pore structure and the electrochemical performance of biochar electrode materials. The advantages and disadvantages of introducing heteroatoms and functional materials on the surface of biochar for supercapacitor electrode are analyzed. Meanwhile, future development trends for biochar materials in this field are also prospected.
3. 题目: Deciphering microbial mechanism underlying soil organic carbon storage in a wheat maize rotation system
期刊: Science of The Total Environment
作者: Xinjie Wu, Pengfei Liu, Carl-Eric Wegner, Yu Luo, Ke-Qing Xiao, Zhenling Cui, Fusuo Zhang, Werner Liesack, Jingjing Peng
摘要: A link between microbial life history and soil organic carbon storage in agroecosystems is presumed, but largely unexplored at the gene level. We aimed to elucidate whether and how differential organic material amendments (manure versus peat-vermiculite) affect, relative to a sole chemical fertilizer treatment, the link between microbial life history and soil organic carbon storage in a wheat-maize rotation field experiment. To achieve this goal, we combined bacterial 16S rRNA gene and fungal ITS amplicon sequencing, metagenomics and the assembly of genomes. Fertilizer treatments had a significantly greater effect on microbial community composition than aggregate size, with soil available phosphorus and potassium being the most important community-shaping factors. Limitation in labile carbon was linked to a K-selected oligotrophic life history (Gemmatimonadetes, Acidobacteria) under a sole chemical fertilizer treatment; defined by a significant enrichment of genes involved in resource acquisition, glycosyl hydrolases, and in competition. By contrast, excess of labile carbon promoted an r-selected copiotrophic life history (Cytophagales, Bacillales, Mortierellomycota) under manure treatment; defined by a significant enrichment of genes involved in cellular growth. A distinct life-history strategy was not observed under peat-vermiculite treatment, but rather a mix of both K-selected (Acidobacteria) and r-selected (Actinobacteria, Mortierellomycota) microorganisms. Compared to a sole chemical fertilizer treatment, soil organic carbon storage efficiency was significantly increased by 26.5% and 50.0% under manure and peat-vermiculite treatments, respectively. Taken together, our results highlight the importance of organic material amendments, but in particular a one-time peat-vermiculite application, to promote soil organic carbon storage as a potential management strategy for sustainable agriculture.
4. 题目: Adsorption behaviors of paper mill sludge biochar to remove Cu, Zn and As in wastewater
期刊: Environmental Technology & Innovation
作者: Zhiyong Xu, Yunqin Lin, Yuejin Lin, De Yang, Haomin Zheng
摘要: Paper mill sludge biochar (PMSB) was produced via pyrolysis in a muffle furnace at 750 °C. Subsequently, PMSB was soaked in the HCl solution and washed by deionized water to obtain minerals and organic materials. The organics were named as demineralized paper mill sludge biochar (DPMSB). It was found that PMSB and minerals had larger pore diameters than DPMSB. Also, the removal efficiencies of Cu, Zn and As were above 95.00% by using PMSB and minerals because of the large pores, abundant carbonates and -OH groups, while the removal efficiencies of Cu, Zn and As by using DPMSB were 40.92%, 87.93% and 94.99%, respectively, owing to the H+ competition to Cu and Zn adsorption but more micropores to enhance As adsorption. The adsorption behavior of PMSB showed that the adsorption isotherms of Cu, Zn and As could be well simulated by the Freundlich model, and the pseudo-second-order model fitted the adsorption kinetics of Zn and As, and the Elovich model fitted the adsorption kinetics of Cu. Moreover, the optimal dosages of PMSB to adsorb Cu, Zn and As were 0.3, 0.3 and 0.1 g/L, respectively. And the pH values of the solution for the efficient adsorption of Cu, Zn and As were 4.00, 6.00 and 2.00, respectively. This work provided basic data for the potential commercial application of PMSB for heavy metals removal from wastewater.
5. 题目: A novel eco-friendly recycling of food waste for preparing biofilm-attached biochar to remove Cd2+ and Pb2+ in wastewater
期刊: Journal of Cleaner Production
作者: Yonghui Xing, Xuesong Luo, Song Liu, Wenjie Wan, Qiaoyun Huang, Wenli Chen
摘要: The development of green and sustainable cleaning technologies to properly reuse food waste and remove heavy metals in wastewater can avoid secondary damage to the environment. Our study proposes an innovative way to prepare an efficient adsorbent by growing biofilm bacteria in food waste and attaching them to biochar also prepared from food waste. Modification of the biochar by bacterial biofilm reduced the specific surface area but increased the average pore and the adsorption performance of Cd2+ and Pb2+. Electrostatic adsorption and the complexation by oxygen-containing functional groups were the main adsorption mechanisms of biofilm-attached biochar, and it was also easily recyclable by re-growth of the biofilm cultured by food waste. In wastewater containing both Cd2+ and Pb2+, the two have competitive adsorption sites on biofilm-attached biochar, but more functional groups participate in removing Cd2+. This study proposes a new idea to reuse food waste and prepare bio-modified biochar adsorbents and provides a strategy to remove Cd2+ and Pb2+ in wastewater by applying biofilm-attached biochar.
6. 题目: Enhanced bioremediation of 2,3’,4,4’,5-pentachlorodiphenyl by consortium GYB1 immobilized on sodium alginate-biochar
期刊: Science of The Total Environment
作者: Xiaofang Ouyang, Hua Yin, Xiaolong Yu, Zhanyu Guo, Minghan Zhu, Guining Lu, Zhi Dang
摘要: 2,3’,4,4’,5-pentachlorodiphenyl (PCB 118), a dioxin-like PCB, is often detected in the environment and is difficult to be aerobically biodegraded. In this study, a novel polychlorinated biphenyl degrading consortium GYB1 that can metabolize PCB 118 was successfully obtained by acclimatization process. To enhance the application performance of free bacterial cells, consortium GYB1 was immobilized with sodium alginate and biochar to prepare SC-GYB1 beads. Orthogonal experiments indicated that the optimal composition of the beads (0.2 g) was 2.0% sodium alginate (SA) content, 2.0% wet weight of cells and 1.5% biochar content, which can degrade 50.50% PCB 118 in 5 d. Immobilization shortened the degradation half-life of 1 mg/L PCB 118 by consortium GYB1 from 8.14 d to 3.79 d and made the beads more robust to respond to environmental stress. The SC-GYB1 beads could even keep considerable PCB degradation ability under 200 mg/L Cd2+ stress. According to 16S rRNA gene analysis, Pseudomonas and Stenotrophomonas played the dominant role in consortium GYB1. And embedding obviously altered the community structure and the key bacterial genera during the PCB removal process. Therefore, the immobilization of bacteria consortium by sodium alginate-biochar enhanced the biodegradation of PCB 118, which will provide new insights into functional microorganisms' actual application for PCB restoration.
7. 题目: Lipids and their δ13C values reveal carbon assimilation and cycling in the methane-seep tubeworm Paraescarpia echinospica from the South China Sea
期刊: Deep Sea Research Part I: Oceanographic Research Papers
作者: Hongxiang Guan, Daniel Birgel, Dong Feng, Jörn Peckmann, Lei Liu, Lihua Liu, Jun Tao
摘要: Gutless tubeworms obtain their nutrition from their bacterial endosymbiotic partners, and the metazoan hosts provide the bacteria with sulfide, carbon dioxide, and molecular oxygen taken up through the plume. At seeps, tubeworms take up sulfide using their posterior end, allowing them to fix carbon dioxide and synthesize organic molecules. Compared to bulk tissue isotope compositions, lipid biomarkers and their compound-specific δ13C values of soft tissues allow to assign nutritional modes of endosymbionts and hosts, as well as associations between endosymbionts and the animal host. In this study, the tubeworm Paraescarpia echinospica retrieved from the Haima seeps in the South China Sea (SCS) at approximately 1400 m water depth was analyzed using 16S rRNA, bulk tissue isotopes, lipid biomarkers, and compound-specific δ13C values. The Lamellibrachia sp. endosymbiont, a phylotype of the Gammaproteobacteria, is a bacterium gaining energy from oxidizing sulfur compounds (thiotrophic endosymbiont). Further, six phylotypes of Gammaproteobacteria and seven phylotypes of Alphaproteobacteria were identified in the trophosome. High contents of n-C16:1ω7, n-C18:1ω7 fatty acids, and n-C16:0 and n-C18:1ω7 fatty alcohols were found in the trophosome, and somewhat lower contents in the plume and vestimentum, consistent with the prevalence of thiotrophic endosymbionts in the trophosome. The fatty acids n-C16:1ω7 and n-C18:1ω7 produced by the endosymbionts yielded δ13C values ranging from −34‰ to −30‰, reflecting the use of marine dissolved inorganic carbon (DIC) rather than DIC derived from anaerobic oxidation of methane. The overall small differences in δ13C values (Δamong tissues ≤3‰) for n-C16:1ω7 and n-C18:1ω7 fatty acids in both symbiont-containing and symbiont-free tissues appear to represent the δ13C signatures of the endosymbionts. Generally, n-C16:1ω7 and n-C18:1ω7 fatty acids should be more 13C-depleted than the respective n-C16:0, n-C18:0 fatty acids resulting from desaturation. However, in this study, the saturated n-C16:0, n-C18:0 fatty acids in soft tissues were 13C depleted by 4‰–10‰ compared to the respective n-C16:1ω7 and n-C18:1ω7 fatty acids, suggesting complex trophic interactions between P. echinospica, its endosymbionts, other bacteria living in P. echinospica, and the environment. Sterols, yielding the lowest δ13C values from −49‰ to −46‰, are interpreted to be derived from bioconversion of dietary sterols by the animal host. The combination of microbial diversity, bulk tissue isotopes, and lipid biomarkers used here is a valuable approach to evaluate the nutritional associations between symbionts and hosts in chemosymbiosis as well as the diet of the animal host.
8. 题目: Mixture of controlled-release and conventional urea fertilizer application changed soil aggregate stability, soil humic acid molecular composition, and nitrogen uptake
期刊: Science of The Total Environment
作者: Yongxiang Gao, Xue Song, Kexin Liu, Taige Li, Wenkui Zheng, Yong Wang, Zhiguang Liu, Min Zhang, Qi Chen, Zeli Li, Ruochen Li, Lei Zheng, Wenlong Liu, Tianyu Miao
摘要: Controlled-release urea (CRU) fertilizer application has been shown to improve crop yield and nitrogen (N) use efficiency. However, its effects when mixed with conventional urea fertilizer on soil aggregate stability, humic acid (HA) molecular composition and crop N uptake remain unclear. Soil and plant samples were collected from a long-term (2008-2019) experiment on field maize (Zea mays L., ‘Zhengdan 958’) which included two types of fertilizers [conventional urea fertilizer (CUF), blended CUF with CRU fertilizer (CRF)], four N application rates (0, 150, 300 and 450 kg ha-1), each in three replicates. The results showed that at 300 kg N ha-1, compared to CUF treatment, the CRF treatment significantly improved soil aggregate characteristics [aggregate content with particle size larger than 0.25 mm (R0.25) by 9.6%, mean weight diameter by 19.8%, and geometric mean diameter by 21.7%]. CRF treatment also increased HA content by 5.5%, fulvic acid (FA) by 5.5%, lignin-like molecules by 0.94 times, and protein-like molecules by 3.69 times. At grain-filling stage, CRF treatments significantly increased the sum of soil NH4+-N and NO3--N content by 23.3-24.5%, sap bleeding rate by 12.8-18.2% and N delivery rate through bleeding sap by 60.6-87.7% compared to CUF treatments at the same N application rate. At the same rate of N application, the CRF treatments significantly improved the average yield during three growing seasons by 9.4-14.0% in contrast with CUF treatments. The regression equations showed that the maximum yield was 8,294 kg ha-1 for CUF at the application rate of 312 kg N ha-1 while it was 9,890 kg ha−1 for CRF at the application rate of 286 kg N ha−1. We conclude that the long-term application of CRF changed the HA molecular structure, enhanced the water stable aggregates, improved crop N uptake, and increased economically viable maize yield.
9. 题目: Soil organic carbon in irrigated agricultural systems: a meta‐analysis
期刊: Global Change Biology
作者: David Emde, Kirsten Hannam, Ilka Most, Louise Nelson, Melanie Jones
摘要: Over the last 200 years, conversion of noncultivated land for agriculture has substantially reduced global soil organic carbon (SOC) stocks in upper soil layers. Nevertheless, practices such as no‐ or reduced tillage, application of organic soil amendments, and maintenance of continuous cover can increase SOC in agricultural fields. While these management practices have been well‐studied, the effects on SOC of cropping systems that incorporate irrigation are poorly understood. Given the large, and expanding, agricultural landbase under irrigation across the globe, this is a critical knowledge gap for climate change mitigation. We undertook a systematic literature review and subsequent meta‐analysis of data from studies that examined changes in SOC on irrigated agricultural sites through time. We investigated changes in SOC by climate (aridity), soil texture, and irrigation method with the following objectives: i) to examine the impact of irrigated agriculture on SOC storage, and ii) to identify the conditions under which irrigated agriculture is most likely to enhance SOC. Overall, irrigated agriculture increased SOC stocks by 5.9%, with little effect of study length (2 – 47 years). However, changes in SOC varied by climate and soil depth, with the greatest increase in SOC observed on irrigated semi‐arid sites at the 0 ‐ 10 cm depth (14.8%). Additionally, SOC increased in irrigated fine‐ and medium‐textured soils but not coarse‐textured soils. Furthermore, while there was no overall change to SOC in flood/furrow irrigated sites, SOC tended to increase in sprinkler irrigated sites, and decrease in drip irrigated sites, especially at depths below 10 cm. This work sheds light on the nuances of SOC change across irrigated agricultural systems, highlights the importance of studying SOC storage in deeper soils, and will help guide future research on the impacts of irrigated agriculture on SOC.
10. 题目: Ball-milled biochar incorporated polydopamine thin-film composite (PDA/TFC) membrane for high-flux separation of tetracyclic antibiotics from wastewater
期刊: Separation and Purification Technology
作者: Dawei Zhang, Kejing Zhang, Xiaolan Hu, Yingwen Xue, Lu Zhang, Yingxia Sun
摘要: Nowadays, attempts emerge in an endless stream to explore an efficient active interlayer to break the “trade-off” relationship between permeability and rejection of conventional thin-film composite (TFC) membrane. Biochar, which is often used as an economically efficient material in soil remediation and wastewater treatment, however, is usually neglected in the application of TFC membrane. This study fabricated a series of polydopamine (PDA)/TFC membranes incorporated with different concentrations of ball-milled biochar (BMBC) interlayer by the combination of conventional interfacial polymerization and bar coating method and employed them in antibiotics wastewater removal. Results indicated that water permeability of the optimized membrane (PDA/TFC-2) improved nearly two-fold (32±1.8 LMHB (L.m-2·h-1·bar-1) versus 18.6±1.6 LMHB for control membrane), and the rejection rates were also the highest (91.9% for chlortetracycline, 90.3% for tetracycline, 81.8% for Ciprofloxacin and 91.3% for oxytetracycline). Furthermore, the fouled PDA/TFC-2 membrane could be easily regenerated by NaOH washing and remained ∼70.6% permeability flux of that of fresh membrane even after five times washing, while the rejection rate was still more than 60%. The findings of our study not only provide a promising material for the separation of antibiotic wastewater but also give a new sight towards the application of biochar in wastewater treatment.
11. 题目: Degradation of cephalexin by persulfate activated with magnetic loofah biochar: performance and mechanism
期刊: Separation and Purification Technology
作者: Haocheng Song, Qiang Li, Yuxuan Ye, Fei Pan, Dajie Zhang, Dongsheng Xia
摘要: Antibiotic contamination has become a serious environmental problem and much attention has been paid to its purification. The sulfate radical (SO4•−) based advanced oxidation processes (AOPs) exhibited significant potential in the treatment of antibiotics. In this study, the magnetic biochar (Fe2O3@LBC) derived from loofah was prepared to activate persulfate (PS) for cephalexin (CEX) degradation. Under the optimal conditions, 73.9% of CEX was removed in the Fe2O3@LBC/PS system. Free radicals quenching experiments and electron paramagnetic resonance (EPR) analysis revealed that HO• and SO4•− were responsible for the degradation of CEX. The C-OH of the catalyst played a crucial role in the degradation process. In addition, the conversion between Fe3+ and Fe2+ enhanced the degradation of CEX by producing SO4•−. The degradation performance of other antibiotics and CEX in different water matrices indicated the broad adaptability and applications of Fe2O3@LBC. The main intermediates and the possible transformation pathways were proposed. These results provided a potential insight into biochar based catalysts for the degradation of antibiotics by activation of persulfate.
12. 题目: Phosphate alters the compositional characteristics of humic acid adsorbed onto goethite
期刊: Journal of Soils and Sediments
作者: ChunYan Luo, ShuaiLong Wen, ShiLin An, YueHan Lu, YingXun Du
摘要: Purpose The adsorption of organic matter and phosphate on minerals is a common natural process that has an important impact on the migration and burial of carbon and phosphorus. Previous studies have focused mainly on the influence of organic matter on the adsorption of phosphate. Yet, the influence of phosphate on the adsorption of different pools of organic matter is not well understood. This study evaluates changes in different organic matter pools during their adsorption to minerals in the presence of phosphate. Materials and methods Firstly, the adsorption behaviors of natural organic matter (i.e., humic acid) and phosphate on goethite were evaluated separately. Secondly, humic acid and phosphate were added to goethite at different orders to elucidate the effect of phosphate on the fractionation of humic acid components adsorbed to goethite. Results and discussion The results showed that when phosphate and humic acid were added simultaneously, goethite was preferentially combined with phosphate. In the absence of phosphate, SUVA254 of the humic acid solution decreased and E2/E3 of the solution increased during the adsorption. Among the six EEM-PARAFAC (excitation-emission matrix fluorescence coupled with parallel factor analysis) components of the humic acid, C1, C2, and C4 (terrestrial humus-like substances) decreased significantly and exhibited strong adsorption, C3 (microbial fulvic-like substance) showed weak adsorption, whereas C5 (photodegradation products) and C6 (tyrosine-like component) did not show evident adsorption. In the presence of phosphate, phosphate inhibited, and replaced the adsorbed C1, C2, and C4, but promoted the adsorption of C5, which increased the aromaticity and the molecular weight of the humic acid solution. Conclusions Our results reveal that phosphate influences the fractionation of humic acid components adsorbed onto goethite, suggesting that phosphate can alter the chemical composition of natural organic matter interacting with minerals and thus impact the burial and fractionation of natural organic matter at the mineral-water interface.
13. 题目: A multi-proxy reconstruction of the late Holocene climate evolution in the Kapsabet Swamp, Kenya (East Africa)
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Dennis M. Njagi, Joyanto Routh, Daniel Olago, Kasun Gaynatha
摘要: Multi-proxy high-resolution records relating to climate and dominant vegetation cover have been obtained from a peat deposit retrieved from the Kapsabet swamp in western Kenya. The 4-m long peat sequence provided a continuous sedimentation record spanning ca. 3023 cal yr BP to the present and is representative of the late Holocene changes in the relatively high-altitude part of the Lake Victoria catchment. Paleoenvironmental factors influencing peat formation and organic matter (OM) source inputs in Kapsabet were reconstructed based on total organic carbon, carbon accumulation rate, δ13C, δ15N, C/N ratio, and specific biomarker-based n-alkane ratios. The Kapsabet peat sequence was divided into five stages based on different climatic conditions: Stage 1 (3023–1670 cal yr BP) represents a progression from cool dry to wet conditions. Stage 2 (1670–1187 cal yr BP) is a relatively warm and wet period with increased productivity and high OM input. Stage 3 (1187–625 cal yr BP) represents gradual warming coeval to the late Holocene Medieval Warm Period. Stage 4 (625–188 cal yr BP) is a cool and wet period with high variability in precipitation and hydrological conditions representing the Little Ice Age. Stage 5 (188 cal yr BP to present) represents a relatively cool and wet period that coincides with the expansion of agriculture, particularly in the lowlands. The proxies indicate a progressive change from a forested landscape to an open woodland coeval to a decline in terrigenous inputs and the advent of more wet conditions. The climate on the highlands was less variable than in the lowlands, which underwent several periods of drought and intermittent wet conditions. The changes in the catchment coincided with the expansion of agriculture and land clearance marking increased human activities in the lowlands. Overall, the Kapsabet peat sequence tracks the regional climatic changes in East Africa and marks a promising sedimentary archive for palaeoclimate reconstruction from a region with a paucity of palaeoenvironmental and palaeovegetation histories.
14. 题目: Poultry litter stabilization by two-stage composting-vermicomposting process: Environmental, energetic and economic performance
作者: Rocio Vicentin, Carolina Elisabet Masín, Maia Raquel Lescano, Cristina Susana Zalazar
摘要: Poultry litter (PL) is a heterogeneous mixture that contains bedding materials, antibiotics, dead skin, feed scraps, water, feathers and the resulting microbiota from poultry production cycle. Although its treatment does not receive attention, it is an important organic resource generated in the north-east region of Santa Fe Province since animal primary production is one of the main economic activities there and in the whole country. The objective of this work was to analyse the economic and energy aspects and the environmental impact of two scenarios corresponding to treat two different mixtures of organic wastes: Eucalyptus sp. sawdust (ES), rice hulls (RH) and PL. PL was considered in two different volume proportions: 1RH:3PL for scenario 1 and 0.5RH:1ES:2PL for scenario 2. The two-stage combined system of composting + vermicomposting was applied to both scenarios and compared; on one hand, the current regulated practice for waste final deposition (landfill) and on the other hand, a base line scenario, which describes the current situation, where the raw material is transported and spread over the field as fertilizer without previous stabilization. The scenario construction was based according to on-site data, lab-scale experiments previously published and software databases. The environmental study was carried out with life cycle assessment; and the energy study, using cumulative energy demand methodology and the energy balance. Based on the results, it was possible to affirm the importance of the integrated agricultural waste treatment to address environmental benefits, especially related to the base line scenario. Furthermore, there were no significant differences between the two proposed scenarios. Economic and environmental results were contradictory when no long-term socio-economic consequences are considered. Combined composting and vermicomposting strategy reduce the organic matter and nutrients content not only to avoid discharges into the environment, but also to replace the fossil fuels consumption during unsustainable techniques as sanitary landfill, producing improved substrates for agricultural use.
15. 题目: Bioturbation and soil resistance to wind erosion in Southern Tunisia
作者: P. Jouquet, T. Henry-des-Tureaux, C. Bouet, M. Labiadh, S. Caquineau, H. Aroui Boukbida, F. Garcia Ibarra, V. Hervé, A. Bultelle, P. Podwojewski
摘要: Wind erosion is a major threat to the sustainability of arid and semi-arid ecosystems. In these environments, biological soil crusts positively impact soil resistance to erosion. Less is known, however, on the impact of soil bioturbation by animals. In Southern Tunisia, bioturbation is mainly carried out by termites, ants and rodents which deposit mineral and organic components on the soil surface in the form of soil sheetings for termites or as soil heaps for ants and rodents. We here question the properties of these soils and measure their resistance to wind erosion. We showed that soil sheetings are made of sand grains linked together by bridges of organic matter, clay particles and other small size minerals such as carbonates and gypsum. The stability of these aggregates is comparable to that of biological soil crusts, despite their very different organizations. Conversely, the soil excavated by ants and rodents mainly consists in individual sand grains, which are impoverished in organic carbon and prone to wind erosion. In conclusion, this study highlights the importance of termites, as key soil bioturbator, on the dynamics of soil aggregates in Southern Tunisia. It also shows that they have an opposite effect than that of ants and rodents on the resistance of soil to erosion.
16. 题目: Effects of different pretreatment methods on biogas production and microbial community in anaerobic digestion of wheat straw
期刊: Environmental Science and Pollution Research
作者: Ya-Ru Kang, Yao Su, Jing Wang, Yi-Xuan Chu, Guangming Tian, Ruo He
摘要: The pretreatment of wheat straw has been recognized to be an essential step prior to anaerobic digestion, owing to the high abundance of lignocellulosic materials. In order to choose economical and effective techniques for the disposal of wheat straw, effects of five pretreatment methods including acid, alkali, co-pretreatment of acid and alkali, CaO2, and liquid digestate of municipal sewage sludge on anaerobic digestion of wheat straw were investigated by analyzing biogas production and organic matter degradation in the study. The results showed that among these pretreatment methods, the methane yield was highest in the liquid digestate pretreated-wheat straw with 112.6 mL gTS−1, followed by the acid, alkali, and CaO2 pretreatments, and the lowest was observed in the co-pretreatment of acid and alkali. Illumina MiSeq sequencing of the microbial communities in the anaerobic digesters revealed that the genera Ruminiclostridium including Ruminiclostridium and Ruminiclostridium 1, Hydrogenispora, and Capriciproducens were the main hydrolytic bacteria, acidogenic bacteria, and acetogenic bacteria, respectively, in the anaerobic digesters. Capriciproducens and Hydrogenispora dominated in the first and the later stages, respectively, in the anaerobic digesters, which could work as indicators of the anaerobic co-digestion stage of sludge and wheat straw. The total solid and SO42−-S contents of the solid digestate and the NH4+-N concentration of the liquid digestate had a significant influence on the microbial community in the digesters. These findings indicated that liquid digestate pretreatment was a potential option to improve the anaerobic digestion of wheat straw, due to the low cost without additional chemical agents.
17. 题目: Effects of an organic carbon source on the coupling of sulfur(thiosulfate)-driven denitration with Anammox process
期刊: Bioresource Technology
作者: Zihe Liu, Wenmin Lin, Qijin Luo, Yuancai Chen, Yongyou Hu
摘要: The sulfur(thiosulfate)-driven autotrophic denitrification coupled with Anammox (SDDA) process is proposed as an emerging technology for wastewater containing NH4+-N and NO3−-N. However, the influence of organic matter on the SDDA process is not fully understood. A long-term experiment has shown that a moderate organic (acetate) (＜140 mg/L COD) can accelerate the heterotrophic/autotrophic denitrification and Anammox activity, to reach as high as 92.8% ± 0.3% total nitrogen at a loading rate of 1.34 kg-N/(m3·d). Batch test results showed that Anammox made the largest contribution to the removal of nitrogen, even in an SDDA system with COD addition. Additionally, organics can promote the bioavailability of solid sulfur through reaction with sulfide to form polysulfides, which increased nitrite accumulation to forward Anammox process. Sulfur-oxidizing bacteria (e.g., Thiobacillus and Denitratisoma) coexisted with Anammox bacteria (e.g., Ca. Brocadia and Ca. Kuenenia) in the SDDA system despite the addition of exogenous COD.
18. 题目: Photocatalytic degradation of humic acid using a novel visible-light active α-Fe2O3/NiS2 composite photocatalyst
期刊: Journal of Environmental Chemical Engineering
作者: Safia Syazana Mohtar, Farhana Aziz, Ahmad Rizam Mohamad Nor, Abdussamad Mukhtar Mohammed, Shakhawan Ahmad Mhamad, Juhana Jaafar, Norhaniza Yusof, Wan Norharyati Wan Salleh, Ahmad Fauzi Ismail
摘要: The effects of α-Fe2O3/NiS2 composite for the humic acid removal were systematically studied and compared with the synthesized α-Fe2O3 and NiS2. The obtained mesoporous composite has a stacked plate-like surface, active at a visible light region with a bandgap of 2.49eV, and has a lower rate of recombination compared to the α-Fe2O3 but higher than the NiS2. The highest humic acid removal (93.7%) was achieved by the α-Fe2O3/NiS2 composite followed by the α-Fe2O3 (88.7%) and NiS2 (86.4%) at optimum conditions of 0.1gL-1 catalyst loading, pH 5, and 30mgL-1 initial humic acid concentration. The mineralization achieved 96.8% and the catalyst stable up to the fourth cycle. These encouraging results were due to the better adsorption capacity of the composite, being active in visible light, and quenching of the photoluminescence that led to effective separation of subsequent reduction in the rate of recombination of the charged carriers.
19. 题目: Bacterial consumption of total and dissolved organic carbon in the Great Barrier Reef
作者: Cátia Carreira, Sam Talbot, Christian Lønborg
摘要: Heterotrophic bacteria typically take up directly dissolved organic matter due to the small molecular size, although both particulate and dissolved organic matter have labile (easily consumed) compounds. Tropical coastal waters are important ecosystems because of their high productivity. However, few studies have determined bacterial cycling (i.e. carbon uptake by bacteria and allocation for bacterial biomass and respiration) of dissolved organic carbon in coastal tropical waters, and none has determined bacterial cycling of total and dissolved organic carbon simultaneously. In this study we followed bacterial biomass and production, and organic carbon changes over short-term (12 days) dark incubations with (total organic carbon, TOC) and without particulate organic carbon additions (dissolved organic carbon, DOC). The study was performed at three sites along the middle stretch of the Great Barrier Reef (GBR) during the dry and wet seasons. Our results show that the bacterial growth efficiency is low (0.1–11.5%) compared to other coastal tropical systems, and there were no differences in the carbon cycling between organic matter sources, seasons or locations. Nonetheless, more carbon was consumed in the TOC compared to the DOC incubations, although the proportion allocated to biomass and respiration was similar. This suggests that having more bioavailable substrate in the particulate form did not benefit bacteria. Overall, our study indicates that when comparing the obtained respiration rates with previously measured primary production rates, the GBR is a heterotrophic system. More detailed studies are required to fully explore the mechanisms used by bacteria to cycle TOC and DOC in tropical coastal waters.
20. 题目: Enhanced nitrogen removal in an electrochemically coupled biochar-amended constructed wetland microcosms: The interactive effects of biochar and electrochemistry
期刊: Science of The Total Environment
作者: Le Zhong, Shan-Shan Yang, Jie Ding, Guang-Yuan Wang, g-Xin Chen Chen, Guo-Jun Xie, Wei Xu, Fang Yuan, Nan-Qi Ren
摘要: The interactive effects of both biochar (BC) and electrochemistry (EC) can affect nitrogen (N) removal process. However, little is known about how this function in constructed wetland (CW) systems. In this study, an electrochemically (EC) coupled BC-amended saturated subsurface vertical flow constructed wetland (BECW) systems were established to enhance nitrogen (N) removal. Other three CW systems: without BC and EC (CW); with EC only (ECW); and with BC only (BCW) were performed as controls. Results indicated that the total nitrogen (59.88%–93.03%) and nitrate‑nitrogen (83.14%–100%) of the BECW system were significantly enhanced (p < 0.05) compared with the control systems. Treated WWTP tail-water could meet Class-IV of the Surface Water Quality Standard (GB3838–2002) in China by the BECW system. The enhanced N removal in the BECW system could be attributed to (1) the autotrophic denitrification process in which H2 and Fe2+ provided by the cathode and anode acted as electron donors; (2) BC addition acting as substrate could improve the activity, diversity and richness of microorganisms. Microbial community analysis further indicated that high N removal in the BECW system was significantly dependent on the synergy between the heterotrophic and autotrophic denitrifiers, facilitated by BC and EC interaction. Results illustrate that the BECW system is a feasible and eco-sustainable technology for treating low C/N tail-water from WWTPs. This work provides a novel and fundamental understanding of the electrochemically coupled biochar-amended CW system. These results could serve as a theoretical basis for the engineered applications in the deep purification of WWTPs' tail-water.