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1.
Bioresour Technol ; 299: 122686, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31902635

RESUMO

Denitrification with non-organic electron donors for treating low C/N ratio wastewater has attracted growing interests. Hydrogen, reduced sulfur compounds and ferrous ions are mainly used in autotrophic denitrification, holding promise for achieving practical applications. Recently, the development of autotrophic denitrification-based processes, such as bioelectrochemically-supported hydrogenotrophic denitrification and sulfur-/iron-based denitrification assisted multi-contaminant removal, provide opportunities for applying these processes in wastewater treatment. Exploration of the autotrophic denitrification process in terms of contaminant removal mechanism, interaction among functional microorganisms, and potential full-scale applications is thus of great importance. Here, an overview of the commonly used non-organic electron donors, e.g., hydrogen, reduced sulfur compounds and ferrous ions, in denitrification for treating low C/N ratio wastewater is provided. Also, the feasibility of applying the combined processes based on autotrophic denitrification with the compounds is discussed. Furthermore, challenges and future possibilities as well as concerns about the practical applications are envisaged in this review.


Assuntos
Desnitrificação , Águas Residuárias , Processos Autotróficos , Reatores Biológicos , Elétrons , Nitratos , Nitrogênio
2.
Bioresour Technol ; 299: 122697, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31902637

RESUMO

Denitratation (NO3-→NO2-)/anammox is a promising method for anammox application in mainstream wastewater treatment plants (WWTPs) to reduce oxygen and organic matter consumption. Achieving nitrite production via denitratation and controlling denitritation (NO2-→N2) is the basis of the denitratation/anammox process. To control denitritation, the denitrifying biocommunity and growth rate are critically reviewed for biocommunity optimization. Then, the short-term and long-term effects of pH on denitritation were summarized and the possible mechanism was discussed, along with the effect of C/N ratio and organic matter type on denitritation. Meanwhile, the strategies for producing nitrite via controlling denitritation are discussed, as well as the processes for achieving nitrogen removal via denitratation/anammox in WWTPs. Finally, the practical application of denitratation/anammox in a full-scale mainstream WWTP is documented.


Assuntos
Desnitrificação , Águas Residuárias , Reatores Biológicos , Nitritos , Nitrogênio , Oxirredução , Esgotos
3.
Bioresour Technol ; 299: 122674, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31902640

RESUMO

The conventional biological nitrogen removal process is receiving increasing pressure partially due to its energy-negative operation. To address this challenge, various mainstream deammonification processes have been explored for energy-neutral municipal wastewater treatment, whereas these processes appear challenging to be sustainably and stably achieved in conventional process configurations. Therefore, this review aimed to provide a comprehensive analysis of the state-of-the-art of mainstream deammonification, while highlighting the major technical challenges. It appeared that recently developed novel dual step process, i.e. A-B processes, could provide a feasible engineering option for mainstream deammonification, where A-stage is designed for COD capture with the aim to enhance energy recovery, and B-stage is tailored for nutrient removal/recovery. This indeed may lead to a promising integrated mainstream deammonification process towards energy-efficient and environmentally sustainable nitrogen removal. Meanwhile, this review also offered an opinion on future municipal wastewater treatment, aiming for concurrent water reclamation and energy recovery.


Assuntos
Eliminação de Resíduos Líquidos , Águas Residuárias , Reatores Biológicos , Nitrogênio , Esgotos
4.
J Agric Food Chem ; 68(4): 961-974, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31910000

RESUMO

Manipulating light transmission by shading is the most effective method of improving the nutritional value and sensory qualities of tea. In this study, the metabolic profiling of two tea cultivars ("Yulv" and "Maotouzhong") in response to different shading periods during the summer season was performed using ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS) and gas chromatography-mass spectrometry (GC-MS). The metabolic pathway analyses showed that the glycolytic pathway and the tricarboxylic acid cycle (TCA cycle) in the leaves and shoots of "Maotouzhong" were significantly inhibited by long-term shading. The nitrogen metabolism in the leaves of the two cultivars was promoted by short-term shading, while it was inhibited by long-term shading. However, the nitrogen metabolism in the shoots of the two cultivars was always inhibited by shading, whether for short or long-term periods. In addition, the intensity of the flavonoid metabolism in both tea cultivars could be reduced by shading. These results revealed that shading could regulate the carbon and nitrogen metabolism and short-term shading could improve the tea quality to some extent.


Assuntos
Camellia sinensis/metabolismo , Camellia sinensis/efeitos da radiação , Carbono/metabolismo , Nitrogênio/metabolismo , Folhas de Planta/química , Camellia sinensis/química , Cromatografia Líquida , Produção Agrícola , Flavonoides/química , Flavonoides/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Luz , Metabolômica , Folhas de Planta/metabolismo , Folhas de Planta/efeitos da radiação , Espectrometria de Massas em Tandem
5.
J Agric Food Chem ; 68(5): 1468-1479, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31945291

RESUMO

In this study, sample processing of bulk commodities using an efficient one-step comminution procedure with liquid nitrogen (LN2) was devised and assessed in the analysis of pesticide residues in fruits and vegetables. LN2 was added to the fresh samples from a tank by opening a valve, and the standard food chopper was kept in a laboratory hood to reduce safety risks. Test portions of four replicates each of 0.25, 0.5, 1, 2, 5, 10, and 15 g were taken from eight fruits and vegetables (tomato, squash, broccoli, apple, grape, peach, green bean, and cucumber) individually comminuted with LN2. For comparison without comminution, similar test portions of a reconstituted freeze-dried certified reference material of pesticides in cucumber were also analyzed by the same method. More than 100 pesticides were monitored by both ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and instrument top sample preparation (ITSP) + fast low-pressure gas chromatography-tandem mass spectrometry (LPGC-MS/MS). A new version of QuEChERS-based sample preparation was followed, in which 5 mL of 4:1 (v/v) acetonitrile/water per gram of sample is used for extraction and 200 µL of initial extract is quickly evaporated, reconstituted in water, and ultracentrifuged for UHPLC-MS/MS analysis. For ITSP+LPGC-MS/MS, another portion of the initial extract undergoes salt-out partitioning with 4:1 (w/w) anhydrous MgSO4/NaCl and the upper layer extract is transferred to an autosampler vial for automated cleanup and analysis in parallel. Quality control spikes were made during the comminution, extraction, cleanup, and analysis steps to isolate and estimate the individual and overall measurement uncertainties of the approach. The recommended test portion size is 2 g for routine monitoring by this approach, but results demonstrated that subsamples as low as 0.5 g typically gave overall biases and relative standard deviations of <10% for nearly all pesticides, commodities, and methods, which is 3-5% lower than previously evaluated sample processing and analytical methods. This approach can be used to improve data quality, laboratory efficiency, and sample throughput in routine monitoring programs for regulatory, risk assessment, and other purposes.


Assuntos
Contaminação de Alimentos/análise , Frutas/química , Ensaios de Triagem em Larga Escala/métodos , Nitrogênio/química , Resíduos de Praguicidas/análise , Verduras/química , Cromatografia Líquida de Alta Pressão , Controle de Qualidade , Tamanho da Amostra , Espectrometria de Massas em Tandem
6.
Waste Manag ; 104: 82-93, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31972456

RESUMO

Thermal hydrolysis pretreatments (THP) coupled to anaerobic digestion (AD) are implemented to treat municipal solids, but limited study indicates whether THP-AD materials merit different land application rates than AD biosolids without THP. Three AD biosolids types with either no pretreatment, THP, or two-hour fermentation were evaluated for differences in leachable dissolved organic matter (DOM), DOM decomposition, and nitrogen (N) releases in biosolids incubated in sandy loam soil. DOM characterizations of size exclusion chromatography, FTIR, and fluorescence maxima > Ex: 400 nm indicated similarities in among AD-DOM that contrasted waste activated sludge Milorganite and Suwannee River Organic Matter (SRNOM). Fluorescence peak picking was a more adaptable analysis for shifted leachate spectra than fluorescence regional integration (FRI). Peak ratio analysis is recommended over FRI for biosolids-DOM. The 3-month net inorganic N produced in biosolids-soil incubations was 155 ± 12.1, 149 ± 18.2, 140 ± 17.4, and 354 ± 15.1 mg N/kg for AD biosolids with no pretreatment, fermentation-AD, THP-AD, and Milorganite respectively. Overall, there was limited evidence of differences in leachable organic matter quality or net mineral N release after 105 days for AD solids with or without THP. Red-shifted fluorescence of leachates decayed by day 45 in aerobic biosolids-soil incubations, suggesting that larger, complex carbon sources liberated during solids stabilization may decompose readily in soils. Overall, other variables (source material, AD operation) may have a greater influence on final nutrient releases and organic matter quality than full-scale pretreatments to AD alone. Critical and targeted application of DOM spectroscopy specific to biosolid-leachates will improve use in advanced stabilization studies.


Assuntos
Nitrogênio , Hidrólise , Esgotos , Solo
7.
J Phys Chem Lett ; 11(3): 1030-1037, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31967828

RESUMO

Very recently, the bulk synthesis of cyclo-N5- from arylpentazole through the treatment with m-chloroperbenzonic acid (m-CPBA) and ferrous bisglycinate ([Fe(Gly)2]) (Zhang, C., et al. Science 2017, 355, 374) has greatly promoted the application of pentazolate anion as a novel high-performance energetic material. Yet the mechanism for this reaction is still unexplored. Herein we perform mechanistic studies on the selective C-N bond cleavage in arylpentazole by using density functional theory methods. The direct C-N bond activation by m-CPBA was computed to be kinetically inaccessible. Instead, the oxidation of [Fe(Gly)2] by m-CPBA is much favorable, which leads to the generation of a high-valent iron(IV)-oxo product. The Fe(IV)-oxo intermediate has been examined by UV-vis absorption spectra experiments and further verified by excited-state calculations. It is found that the Fe(IV)-oxo serves as the key intermediate for the C-N bond activation of arylpentazole and the cyclo-N5- generation. Our calculations clarified the key mechanistic details of the cyclo-N5- generation, and the factors that affect the production yield are further discussed.


Assuntos
Clorobenzoatos/química , Compostos Ferrosos/química , Glicina/química , Modelos Moleculares , Pentilenotetrazol/química , Carbono/química , Nitrogênio/química , Oxirredução , Teoria Quântica , Espectrofotometria , Termodinâmica
8.
Ying Yong Sheng Tai Xue Bao ; 31(1): 17-24, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957376

RESUMO

We investigated the concentrations of carbon (C), nitrogen (N), and phosphorus (P) and C:N:P stoichiometry in soil and litter of Pinus massoniana forest under four different management patterns: inefficient forest transformation, mixture of arbor with shrub and herb, shallow ditch grass planting, and being banned in serious erosion and degradation of red soil in southern China. Our findings could provide scientific basis for soil erosion control and vegetation restoration in this area. The results showed that there were significant differences in soil organic carbon (SOC), TN, TP and litter nutrient content among different management patterns. The nutrient contents in soil and litter under all the four management patterns were significantly higher than that of control, with mixture of arbor with shrub and herb having the highest concentrations. The concentrations of SOC, TN and TP decreased with the increases of soil layer. However, the shallow ditch grass planting mana-gement pattern presented as follows: the concentrations of SOC, TN and TP decreased first and then increased with the increases of soil layer, with the lowest value in 5-20 cm soil layer. There were significant differences in soil C:N, C:P, N:P and litter C:P among different management patterns, and the soil spatial variation was C:N>C:P>N:P. Excepted for mixture of arbor with shrub and herb, C:N was still at a lower level in the other management patterns, and soil C:P and N:P showed higher values overall. Litter C:N, C:P and N:P had opposite change pattern, with inefficient forest transformation and mixture of arbor with shrub and herb being much smaller than the control. Soil C:N and C:P were mainly controlled by SOC content and litter C content, and soil N:P was mainly controlled by soil TP content and litter P content. Soil stoichiometry was affected by soil water content, soil bulk density, pH, and other factors. The relationship between litter and soil nutrients was closely related and showed similar changes.


Assuntos
Pinus , Solo , Carbono , China , Florestas , Nitrogênio
9.
Ying Yong Sheng Tai Xue Bao ; 31(1): 25-34, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957377

RESUMO

To examine the effects of management measures on carbon and nitrogen contents, as well as their distribution and structural characteristics of different soil fractions in Moso bamboo plantations, we compared three types of the bamboo forests (undisturbed, extensively managed, and intensively managed) and the control secondary broadleaved evergreen forest using the methods of physical fractionation, chemical and biological analysis and Fourier-transform infrared spectroscopy (FTIR). The results showed that soil total organic carbon (TOC) and total nitrogen (TN) content, as well as free particulate organic carbon and nitrogen, soluble organic carbon and nitrogen (DOC, DON), and mineral-associated organic carbon and nitrogen in the undisturbed and extensively managed Moso bamboo plantations were significantly increased compared with that in the control. The distribution ratio of free particulate organic carbon and nitrogen in the undisturbed Moso bamboo plantation significantly increased, with mineral-associated organic carbon being the largest reservoir of soil organic carbon (67.6%). Intensive management resulted in the decrease of soil organic carbon, total nitrogen storage, and the contents of each component, but significantly increased DOC/TOC, the ratio of microbial biomass nitrogen to TN as well as the ratio of microbial biomass carbon to TOC (microbial quotient). Management measures significantly affected the chemical structure of SOC. Compared with the control, the relative intensities of phenolic and alcoholic-OH, aliphatic methyl and methylene, aromatic C=C, and carbonyl C=O absorption were higher in the SOC of undisturbed and extensively managed Moso bamboo plantations, and soil hydrophobicity was significantly increased. Results from correlation analysis showed that soil hydrophobicity and the content of aliphatic and aromatic groups were negatively correlated with microbial quotient and positively correlated with TOC and TN content. In conclusion, the increased inputs of organic matter residues (such as litter and roots) could contribute to the relative accumulation of chemical resistance compounds with reduced human disturbance, which significantly enhanced chemical stability of soil organic carbon. Soil clay minerals played a key role in protecting soil organic carbon through the formation of mineral-organic compounds, which facilitate the stability of soil carbon storage and the long-term preservation of soil carbon.


Assuntos
Carbono , Nitrogênio , China , Florestas , Humanos , Poaceae , Solo
10.
Ying Yong Sheng Tai Xue Bao ; 31(1): 129-138, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957389

RESUMO

We examined the effects of a combination of slow-release urea (PCU) and common urea (PU) applied at different soil depths (0-30 cm soil layer) on inorganic nitrogen content, enzyme activity, and crop yield during two years (2017-2018) in a field experiment. There were eight treatments: CK (without N fertilizer); PU1(common urea applied at 5-10 cm deep soil layer); PU2(common urea applied at 5-10 cm deep soil layer, 60% seed fertilizer + 40% topdressing); PU3(20% common urea at 5-10 cm soil depth, 30% common urea at 15-20 cm soil depth, 50% common urea at 25-30 cm soil depth); PCU1(20% total nitrogen application rate at 5-10 cm soil depth, 30% total nitrogen application rate at 15-20 cm soil depth, 50% total nitrogen application rate at 25-30 cm soil depth), the N fertilizer at 5-10 cm was common urea, but, at 15-20 and 25-30 cm, it was a combination of PCU and PU at ratios of 3:7 and 3:7; PCU2 was as PCU1 but the ratio of PCU and PU was 5:5 at 15-20 cm and 5:5 at 25-30 cm; in PCU3, the ratio of PCU and PU was 3:7 at 15-20 cm and 5:5 at 25-30 cm; in PCU4, the ratio of PCU and PU was 5:5 at 15-20 cm and 3:7 at 25-30 cm. The results showed that PU1 could meet nitrogen demand at the 0-10 cm layer in the early growth stage compared with CK. PU2 and PU3 could meet nitrogen demand for 10-30 cm soil layer in the early stage of maize development. The combined application of slow release urea and common urea could meet nitrogen demand for the whole growth period of maize. In the filling and maturing period, combined application of slow release and common urea significantly increased not only NO3--N, NH4+-N, and alkali-hydrolyzed nitrogen contents but also urease and protease activities in the 10-20 cm and 20-30 cm soil layers compared with PU1-PU3. Compared with PU3, maize yield increased by 2.3%-24.6% and 1.3%-16.5% in the PCU1-PCU4 treatments in 2017 and 2018, respectively. PCU4 had the highest yield, with 13899 and 12439 kg·hm-2, respectively. Therefore, the combined application of slow-release and common urea at different soil layers could meet nitrogen demand in the early growth stage of maize and increase the content of inorganic nitrogen and enzyme activities in the 10-30 cm soil layers in the later growth period, which promoted the growth and increased the yield of maize. Among all the treatments PCU4 treatment was the most effective.


Assuntos
Nitrogênio , Solo , Agricultura , Fertilizantes , Ureia , Zea mays
11.
Ying Yong Sheng Tai Xue Bao ; 31(1): 139-147, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957390

RESUMO

To reveal the coupling effect of water and fertilizer on the yield of spring maize under shallow-buried drip irrigation in semi-arid area of western Liaoning, a field experiment was conducted with the quadratic regression orthogonal design of three factors (water, nitrogen and potassium) crossed with five levels in 2017-2018. A quadratic regression model was established with yield (Y) as the dependent variable and irrigation amount (W), nitrogen (N) and potassium (K) application amounts as independent variables to analyze the coupling relationships between Y and W, N and K, respectively. The results showed that the shallow-drip irrigation water-fertilizer coupling had significant impact on yield. The single factor of W, N and K promoted the yield, with their effects ranking as W>N>K. The effect of two-factor interaction on yield increased first and then decreased which ranked as WN>WK>NK. Considering the three-factor coupling effect on yield, the combination of abundant water, nitrogen and potassium was the highest, followed by high water, nitrogen and potassium, and low water, nitrogen and potassium the lowest. As the optimal treatments found by the model, we obtained the suitable water-fertilizer application range of shallow-buried drip irrigation with higher target yield of 8000-8810 kg·hm-2, that was, the irrigation amount was 43-61 mm, nitrogen 138-343 kg·hm-2 and potassium 79-163 kg·hm-2 under the ambient natural rainfall. The results provided a referable basis for application of water-fertilizer integrated cropping pattern under shallow-buried drip irrigation in semi-arid area of northern China.


Assuntos
Fertilizantes , Zea mays , Irrigação Agrícola , Agricultura , Biomassa , China , Nitrogênio , Água
12.
Ying Yong Sheng Tai Xue Bao ; 31(1): 148-156, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957391

RESUMO

Field experiment was conducted to examine the effects of combined application of N and Zn fertilizers on translocation, distribution, and accumulation of Zn in different organs in wheat plants. The results showed that Zn concentration and Zn accumulation in each organ were significantly different under different treatments. Compared with N3 (120 kg·hm-2), the grain Zn concentration of N1 (240 kg·hm-2) and N2 (180 kg·hm-2) increased 22.0% and 8.9%, respectively. Compared with the non-Zn application treatment (CK), grain Zn concentration under ZnS (soil Zn fertilization), ZnF (foliar Zn fertilization), and ZnS+ZnF (soil Zn fertilization combined with foliar Zn fertilization) treatments were increased by 5.4%, 60.5% and 72.8%, while Zn accumulation in grain were increased by 21.3% 82.5% and 102.4%, respectively. Zn in grain mainly came from the remobilization of Zn uptaken after antheis, with the accumulative contribution being 89.9% and 100.0% in ZnF and ZnS+ZnF, respectively. Compared with ZnS, Zn fertilizer recovery and use efficiency of ZnF and ZnS+ZnF were increased by 4.8, 1.1 times and 7.9, 2.2 times, respectively. Under current condition, Zn concentration and Zn accumulation in different organs of wheat increased with increasing N rate when it was less than 240 kg·hm-2, which was significantly increased in the grain by foliar Zn application. Therefore, Zn concentration and Zn accumulation in wheat grain could be increased by maintaining the high-yield N fertilization and combining the foliar Zn application in the late growth stage, which would improve Zn nutritional quality of wheat grain.


Assuntos
Triticum , Zinco , Grão Comestível , Fertilizantes , Nitrogênio , Solo
13.
Ying Yong Sheng Tai Xue Bao ; 31(1): 157-164, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957392

RESUMO

Understanding the effects of long-term fertilization on soil organic phosphorus fractions and wheat yield in the Loess Plateau can provide theoretical support for improving phosphorus conversion, utilization, and rational use of fertilizer. We examined the effects of different fertilizer treatments on soil organic phosphorus fractions, wheat yield and soil properties of a farmland in the long-term (1984-2016) positioning test station of Changwu loess soil. There were eight treatments, including no fertilizer (CK), single application of nitrogen fertilizer (N), single application of phosphorus fertilizer (P), application of nitrogen and phosphorus fertilizer (NP), single application of organic fertilizer (M), nitrogen combined with organic fertilizer (MN), phosphorus combined with organic fertilizer (MP), nitrogen and phosphorus combined with organic fertilizer (MNP). The results showed that the range of soil organic phosphorus content was 244.7-429.1 mg·kg-1 after long-term fertilization. Except for the N treatment, organic phosphorus content was significantly increased by 15.4%-47.9% compared to CK. Long-term application of phosphorus fertilizer changed the content of organic phosphorus fractions in the surface soil (0-20 cm). The treatments of MP and MNP significantly increased the contents of labile organic phosphorus and moderately labile organic phosphorus. The treatments of N, P and NP significantly reduced the content of moderately stable organic phosphorus. The treatments of N, P, NP, MN, MP, MNP all significantly increased the highly stable organic phosphorus. The ratio of soil organic phosphorus fractions to total organic phosphorus content was in order of moderately labile organic phosphorus > highly stable organic phosphorus > labile organic phosphorus > moderately stable organic phosphorus. After long-term fertilizer application, the combination of nitrogen and phosphorus fertilizers, especially with organic fertilizers, significantly increased wheat biomass yield and grain yield. Among all the examined soil properties, organic matter, Olsen-P and total inorganic phosphorus were significantly positively correlated with wheat yield. MP and M could significantly increase the content of Olsen-P, total phosphorus, total inorganic phosphorus, labile organic phosphorus and moderately labile organic phosphorus in the loess soil of Loess Plateau. Our results indicated that the organic and phosphorus fertilizers could improve soil phosphorus components that could be more easily absorbed by crops. In summary, the combination of nitrogen and phosphorus fertilizers, especially with organic fertilizers, could increase soil phosphorus supply in the region and promote the wheat yield, which is important for improving soil quality in the Loess Plateau.


Assuntos
Fósforo , Solo , Agricultura , Fazendas , Fertilizantes , Esterco , Nitrogênio , Triticum
14.
Ying Yong Sheng Tai Xue Bao ; 31(1): 182-188, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957395

RESUMO

Pot culture and field experiments were carried out with one-year-old apple rootstock M9T337 seedlings and five-year-old 'Yanfu3'/SH6/M. hupehensis Rehd. as test materials respectively. Combined with 15N and 13C isotope tracer technology, we examined the effects of different concentrations of NR inhibitor Na2WO4(0, 0.5, 1, 1.5 mmol·L-1, expressed by CK, T1, T2 and T3 respectively) on 15N absorption and 13C accumulation of seedling and apple quality. The results showed that 0.5-1.0 mmol·L-1 Na2WO4 significantly inhibited shoot growth but not root growth of seedling in the pot experiment. Root growth was significantly inhibited when the concentration of Na2WO4 reached 1.5 mmol·L-1. The NR activity of each treatment was negatively correlated with the concentrations of Na2WO4 in the same period, with an order of CK>T1>T2>T3. The content of nitrate in leaves showed the trend of first rising and then decreasing with the extension of processing time. Nitrate content was positively correlated with Na2WO4 concentration in the same period, with an order of T3>T2>T1>CK. Spraying Na2WO4 reduced the 15N absorption of each organ and 15N utilization rate, with such effects increasing with the amount of spraying. With the increases of Na2WO4 concentration, 13C accumulation on the ground increased first and then decreased, with highest value in T2 treatment. The 13C accumulation of whole plant showed a similar pattern. The results of field experiment showed that Na2WO4 application reduced nitrogen contents of leaves and fruits at maturity stage, and increased the anthocyanin content in peel, soluble solids, soluble sugar content and sugar acid ratio in fruits. The T2 treatment showed the best effect. In summary, T2 treatment (1.0 mmol·L-1 Na2WO4) could inhibit shoot growth of seedlings, reduce 15N absorption and utilization, improve 13C accumulation, which would improve apple quality.


Assuntos
Malus , Frutas , Nitrogênio , Folhas de Planta , Plântula
15.
Ying Yong Sheng Tai Xue Bao ; 31(1): 282-292, 2020 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-31957406

RESUMO

Brown tide that occurred in Qinhuangdao coastal waters from 2009 to 2015 caused huge losses of local marine aquaculture and coastal tourism, with devastating effects on marine ecosystems. Nutrients are important biogenic elements for algal growth. It is of great significance to examine the fluctuation characteristics of nutrients in the process of brown tide to understand the nutritional mechanism of brown tide. Based on the survey data of 30 stations located in Qinhuangdao coastal area from April to June 2014, we analyzed nutrient characteristics during the occurrence of brown tide and its relationship with the population dynamics of Aureococcus anophagefferens. The results showed that the concentration of dissolved nitrogen (DN) in April, May and June 2014 was 265.65, 355.36 and 323.71 µg·L-1 respectively, and the concentration of dissolved organic nitrogen (DON) was 196.98, 242.88 and 177.69 µg·L-1, accounting for 74.2%, 68.3% and 54.9% of DN, respectively. The concentration of dissolved phosphorus (DP) in April, May and June was 15.95, 11.39 and 11.14 µg·L-1 respectively. In April and May, PO43--P accounted for a large proportion of the DP, 74.8% and 80.9% respectively. In June, the proportion of PO43--P in DP fell to 33.8%, and the proportion of dissolved organic phosphorus (DOP) in DP rose to 66.2%. The concentration of SiO32--Si in April, May and June was 70.95, 181.13 and 120.68 µg·L-1, respectively. Except for dissolved inorganic nitrogen (DIN) in May and DON, the distribution of other nutrients had clear characteristics that it decreased gradually from inshore to the offshore, with the relatively high concentrations in river mouth. Through R-factor analysis and nutrient structure analysis, it was found that in April, brown tide was at the development stage, and DOP might be the main driving factor for the growth of A. anophagefferens. In May, brown tide was at the maintenance stage, and water temperature became the main controlling factor. When water temperature was higher than 12 ℃, brown tide could occur. In June, brown tide began to decay, and PO43--P had greater effects on the community structure of phytoplankton. DON was the important factor causing the outbreak of brown tide, with a concentration threshold of 150 µg·L-1 and the ratio DON/DIN being greater than 1.


Assuntos
Ecossistema , Água do Mar , China , Nitrogênio , Nutrientes , Fósforo
16.
Bioresour Technol ; 301: 122672, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31945681

RESUMO

The objective of this study was to evaluate the performance of an outdoor membrane-coupled high-rate algal pond equipped with industrial-scale membranes for treating urban wastewater. Decoupling biomass retention time (BRT) and hydraulic retention time (HRT) by membrane filtration resulted in improved process efficiencies, with higher biomass productivities and nutrient removal rates when operating at low HRTs. At 6 days of BRT, biomass productivity increased from 30 to 66 and to 95 g·m-3·d-1 when operating at HRTs of 6, 4 and 2.5 days, respectively. The corresponding nitrogen removal rates were 4, 8 and 11 g N·m-3·d-1 and the phosphorous removal rates were 0.5, 1.3 and 1.6 g P·m-3·d-1. The system was operated keeping moderate specific air demands (0.25 m3·m-2·h-1), resulting in reasonable operating and maintenance costs (€0.04 per m3) and energy requirements (0.29 kWh per m3). The produced water was free of pathogens and could be directly used for reusing purposes.


Assuntos
Águas Residuárias , Purificação da Água , Biomassa , Nitrogênio , Tanques , Eliminação de Resíduos Líquidos
17.
Bioresour Technol ; 301: 122798, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31981907

RESUMO

The polyvinyl formal (PVFM) biocarrier addition in a membrane bioreactor (MBR) was evaluated at high and low carbon/nitrogen (C/N) ratio of 20.0 and 6.7. Results indicated that static biocarrier addition could enrich nitrification and denitrification bacteria, dominating by Tauera, Amaricoccus and Nitrosospira at the genus level and slightly improved the total nitrogen removal even at a low C/N ratio. The bulk sludge characteristics (such as bigger particle size, lower SMP, lower SMP P/C) were also significantly changed in the hybrid MBR (HMBR), leading to a more sustainable membrane operation. The biocarrier addition also reduced the relative abundance of Sphingobacterials_unclassified, Ohtaekwangia and Rhodocyclaceae_unclassified at the genus level, indicating less membrane fouling in the HMBR. Consequently, HMBR with static PVFM addition could partially overcome the drawback of low C/N ratio for total nitrogen removal and membrane fouling control, providing a more resilient MBR to the undesirable environment such as low C/N ratio.


Assuntos
Microbiota , Nitrogênio , Reatores Biológicos , Desnitrificação , Membranas Artificiais , Esgotos , Eliminação de Resíduos Líquidos
18.
Bioresour Technol ; 301: 122758, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31986373

RESUMO

Cultivating sand-consolidating cyanobacteria using wastewater has unique advantages on both nutrients recycling and ecological restoration by transferring excessive nutrients from wastewaters to desert areas. Although previous study showed that sand-consolidating cyanobacterium well adapted to synthetic domestic wastewater, no study has been carried out on actual wastewater. This study aims to investigate the sand-consolidating cyanobacterial biomass production and nutrients removal by cultivating Scytonema hyalinum in the municipal wastewater under different temperatures. The results showed that biomass accumulation increased with temperature from 20 â„ƒ to 30 â„ƒ, while severely depressed at 35 â„ƒ. More than 81.63% sCOD, 90.64% TDN and 97.08% TDP were removed by day 30 under each temperature except for 35℃. The inoculation of S. hyalinum strongly regulated the native wastewater bacterial community. These results indicated that sand-consolidating cyanobacterium S. hyalinum well adapted to municipal wastewater and temperature had remarkable effects on cyanobacterial biomass accumulation, nutrients removal and wastewater native bacterial community dynamics.


Assuntos
Cianobactérias , Águas Residuárias , Biomassa , Nitrogênio , Nutrientes , Areia , Temperatura Ambiente
19.
Bioresour Technol ; 301: 122808, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31987490

RESUMO

This review reports the use of zeolites in biological processes such as anaerobic digestion, nitrification, denitrification and composting, review that has not been proposed yet. It was found that aerobic processes (activated sludge, nitrification, Anammox) use zeolites as ion-exchanger and biomass carriers in order to improve the seattlebility, the biomass growth on zeolite surface and the phosphorous removal. In the case of anaerobic digestion and composting, zeolites are mainly used with the aim of retaining inhibitors such as ammonia and heavy metals through ion-exchange. The inclusion of zeolite effect on mathematical models applied in biological processes is still an area that should be improved, including also the life cycle analysis of the processes that include zeolites. At the same time, the application of zeolites at industrial or full-scale is still very scarce in anaerobic digestion, being more common in nitrogen removal processes.


Assuntos
Zeolitas , Reatores Biológicos , Desnitrificação , Nitrificação , Nitrogênio , Esgotos , Resíduos Sólidos , Águas Residuárias
20.
Oecologia ; 192(2): 323-339, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31901980

RESUMO

While foliar photosynthetic relationships with light, nitrogen, and water availability have been well described, environmental factors driving vertical gradients of foliar traits within forest canopies are still not well understood. We, therefore, examined how light availability and vapour pressure deficit (VPD) co-determine vertical gradients (between 12 and 42 m and in the understorey) of foliar photosynthetic capacity (Amax), 13C fractionation (∆), specific leaf area (SLA), chlorophyll (Chl), and nitrogen (N) concentrations in canopies of Fagus sylvatica and Abies alba growing in a mixed forest in Switzerland in spring and summer 2017. Both species showed lower Chl/N and lower SLA with higher light availability and VPD at the top canopy. Despite these biochemical and morphological acclimations, Amax during summer remained relatively constant and the photosynthetic N-use efficiency (PNUE) decreased with higher light availability for both species, suggesting suboptimal N allocation within the canopy. ∆ of both species were lower at the canopy top compared to the bottom, indicating high water-use efficiency (WUE). VPD gradients strongly co-determined the vertical distribution of Chl, N, and PNUE in F. sylvatica, suggesting stomatal limitation of photosynthesis in the top canopy, whereas these traits were only related to light availability in A. alba. Lower PNUE in F. sylvatica with higher WUE clearly indicated a trade-off in water vs. N use, limiting foliar acclimation to high light and VPD at the top canopy. Species-specific trade-offs in foliar acclimation to environmental canopy gradients may thus be considered for scaling photosynthesis from leaf to canopy to landscape levels.


Assuntos
Fagus , Fotossíntese , Luz , Nitrogênio , Folhas de Planta , Suíça , Pressão de Vapor
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