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1.
J Environ Manage ; 259: 109649, 2020 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-32072941

RESUMEN

In recent years, many studies have been conducted on using different filter media in bioretention systems for stormwater runoff treatment. This critical review paper provides a comprehensive review on the current state of water treatment residual (WTR), a recycled material that can be used as bioretention filter media for removals of key stormwater runoff pollutants (especially phosphorus) and future perspectives with innovative modification on WTR applied for pathogen removal from stormwater runoff. This review paper comprised (i) a brief summary of the reported WTR characteristics, (ii) a thorough evaluation of WTR performance on major pollutants removal from stormwater runoff (iii) a discussion on phosphorus removal mechanisms by WTR applied in the stormwater runoff treatment, and (iv) a review of the future perspectives of WTR for pathogen removal and other potential practical application in the field of stormwater treatment. As outlined in this review, WTR in stormwater runoff treatment has yet to be fully explored. The possible enhancements, especially metal surface modification on WTR are reviewed to bring about the widespread use of WTR in stormwater reuse practices.


Asunto(s)
Contaminantes Ambientales , Contaminantes Químicos del Agua , Purificación del Agua , Fósforo , Lluvia , Abastecimiento de Agua
2.
J Environ Manage ; 259: 109700, 2020 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-32072947

RESUMEN

In the present study, various co-composts of sewage sludge (SS), farm manure (FM) and rock phosphate (RP) were prepared and their influence on phosphorus (P) uptake, soil P restoration and growth of rice crop and residual effect on wheat crop were investigated. The treatments comprised of T1 (control, no amendment), T2 (452 kg Nitrophos ha-1, T3 (724 kg SS50:FM50 ha-1), T4 (594 kg SS100:FM0 ha-1), T5 (728 kg SS25:FM25:RP50 ha-1), T6 (726 kg SS5O:FM25:RP25 ha-1), T7 (508 kg SS75:FM0:RP25 ha-1), and T8 (546 kg SS50:FM0:RP50 ha-1). The post-experimental soil samples were analyzed for pH, EC, OM, Olsen's P. The plant samples (grains and straw of both crops) were analyzed for concentrations of P, and heavy metals. The P adsorption by post-wheat composts-amended soil was tested through Langmuir, and Freundlich adsorption isotherms. The investigated parameters (biomass, grain and straw yield, plant height and P concentrations in plant parts) were significantly increased in all composts as compared to the control treatment. The P uptake by the plants was higher in compost treatments as compared to the control and NP that shows long-term residual effect of applied composts. The maximum grain yield (1.63 Mg ha-1) was obtained in T5 followed by T6 (1.52 Mg ha-1). The P concentration in rice grains were recorded in the trend as T8 (2.55%) > T6 (2.24%) > T4 (1.92%) = T3 (1.88%) > T7 (1.62%). It is evident that the combined application of FM (25%) and RP (50%) enhanced the effect of SS (25%) in terms of P bioavailability and yield parameters and can be effectively used as P fertilizer.


Asunto(s)
Compostaje , Oryza , Granjas , Fertilizantes , Estiércol , Fosfatos , Fósforo , Aguas del Alcantarillado , Suelo , Triticum
3.
J Environ Manage ; 259: 109783, 2020 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-32072952

RESUMEN

Large volume of wastewater consisting complex forms of organics, lipids and nutrients, is discharged from the abattoir (red meat) processing industry. In this study, nutrient rich pre-Anaerobic Membrane Bioreactor (AnMBR) treated abattoir effluent was fed to a struvite (MgNH4PO4.6H2O) precipitator to evaluate the possibility of developing an innovative environmentally sustainable treatment technology to produce nutrient free high-quality treated effluent. A series of continuous and batch experiments were conducted to investigate the influence of pH and presence of Ca2+ on struvite precipitation. The study found that Mg2+:Ca2+ molar ratio of 0.8 (or high Ca2+) impacts on the production and quality of struvite significantly. Pre-AnMBR treated abattoir wastewater with negligible Ca2+ (Mg2+:Ca2+ molar ratio > 20) showed over 80% removal of phosphorus via struvite precipitation. The highest removal rates of both nitrogen and phosphorus were achieved at pH 9.5 with Mg2+:PO43- molar ratio of 2:1.


Asunto(s)
Mataderos , Aguas Residuales , Reactores Biológicos , Precipitación Química , Nutrientes , Fosfatos , Fósforo , Estruvita , Eliminación de Residuos Líquidos
4.
J Environ Manage ; 259: 109826, 2020 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-32072954

RESUMEN

The integration of one anaerobic reactor in the mainstream (AMSR) of a pre-denitritication-MBR was evaluated with the aim to achieve simultaneous sludge minimization and phosphorous removal. The excess sludge production was reduced by 64% when the AMSR was operated under 8 h of hydraulic retention time (HRT). The highest nutrients removal performances referred to organic carbon (98%), nitrogen (90%) and phosphorous (97%) were obtained under 8 h of HRT. In contrast, prolonged anaerobic-endogenous conditions were found to be detrimental for all nutrients removal performances. Similarly, the lowest membrane fouling tendency (FR = 0.65∙1011 m-1 d-1) was achieved under 8 h of HRT, whereas it significantly increased under higher HRT. The highest polyphosphate accumulating organisms kinetics were achieved under HRT of 8 h, showing very high exogenous P-release (46.67 mgPO4-P gVSS-1 h-1) and P-uptake rates (48.6 mgPO4-P gVSS-1 h-1), as well as a not negligible P-release rate under endogenous conditions at low COD/P ratio (≈1).


Asunto(s)
Reactores Biológicos , Aguas del Alcantarillado , Membranas Artificiales , Nitrógeno , Fósforo , Eliminación de Residuos Líquidos
5.
Bioresour Technol ; 302: 122816, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32004813

RESUMEN

This study aimed to clarify the effect of excess activated sludge (EAS) on vermicomposting of fruit and vegetable wastes (FVW). For this, a novel vermireactor consists of substrate and bed compartments was used for treating five types of FVW (banana peels, cabbage, lettuce, carrot, and potato) with and without the addition of EAS by earthworms. The EAS promoted the growth and cocoon production of earthworms, and the decomposition efficiency of FVW. The changes of dehydrogenase activity revealed that the EAS enhanced the microbial activity in all treatments except for the carrot. The organic matter content, total carbon and the C/N ratio showed a significant decrease after addition of EAS into FVW. The content of nitrogen and phosphorus was also improved in the final products after vermicomposting. This study suggested that the addition of EAS could be a feasible option to enhance the vermicomposting of FVW.


Asunto(s)
Oligoquetos , Verduras , Animales , Frutas , Fósforo , Aguas del Alcantarillado , Suelo
6.
Bioresour Technol ; 302: 122817, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32007309

RESUMEN

The basic concepts of circular bioeconomy are reduce, reuse and recycle. Recovery of recyclable nutrients from secondary sources could play a key role in meeting the increased demands of the growing population. Wastewaters of different origin are rich in energy and nutrients sources that can be recovered and reused in a circular bioeconomy perspective. Microalgae can effectively utilize wastewater nutrients for growth and biomass production. Integration of wastewater treatment and microalgal cultivation improves the environmental impacts of the currently used wastewater treatment methods. This review provides comprehensive information on the potential of using microalgae for the recovery of carbon, nitrogen, phosphorus and other micronutrients from wastewaters. Major factors influencing large scale microalgal wastewater treatment are discussed and future research perspectives are proposed to foster the future development in this area.


Asunto(s)
Microalgas , Biomasa , Nitrógeno , Fósforo , Aguas Residuales
7.
Bioresour Technol ; 302: 122583, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32014734

RESUMEN

This study aimed to present a strategy that utilizing semi-continuous flow primary sludge fermentation liquor as carbon source for anaerobic- multistage anaerobic/oxic (A-MAO) process to treat low chemical oxygen demand (COD) and total nitrogen (TN) (C/N) ratio municipal wastewater. The results showed that adding fermentation liquor resulted in average TN and total phosphorus (TP) concentration in effluent decreased from 33 and 2.80 mg L-1 to 9.2 and 0.23 mg L-1, respectively, which met wastewater discharge standard. High-throughput sequencing results indicated that bacterial richness increased and diversity decreased with fermentation liquor adding, and the dominant genera varied from Methylophilaceae and Methylotenera to unclassified_f_Rhodocyclaceae, noran k_f__env.OPS_17, and Azospira. Meanwhile, the abundance of metabolism and organismal systems in A-MAO process rose from 48.42% and 0.74% to 49.52% and 0.78%. The improvement of nitrogen and phosphorus removal with fermentation adding was based on the increment of enzyme coding genes in nitrogen and phosphorus pathway.


Asunto(s)
Aguas del Alcantarillado , Aguas Residuales , Anaerobiosis , Reactores Biológicos , Fermentación , Monoaminooxidasa , Nitrógeno , Nutrientes , Fósforo , Eliminación de Residuos Líquidos
8.
Water Res ; 171: 115450, 2020 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-31901684

RESUMEN

Reclaiming abundant phosphorus from sewage sludge (SS) via pyrolysis for use as a fertilizer has gained increasing attention owing to the rapid depletion of global P reserves. In this study, the enhancement effect of Ca-based additives on sludge P transformation to hydroxylapatite through pyrolysis was systematically investigated. Three Ca-based additives were added in the pyrolysis of SS, and they were found to promote the conversion of sludge P to hydroxylapatite, which is bioavailable to plants. The characterization of the sludge-derived pyrochars indicated that the addition of 10% CaO, 5% Ca(OH)2, or 10% Ca3(PO4)2 facilitated peak hydroxylapatite production. The thermodynamic simulation of the production of hydroxylapatite during pyrolysis showed that these additives increased the enthalpy of the pyrolysis system. Furthermore, the pyrolysis with CaO addition had the lowest enthalpy, thereby suggesting that the addition of CaO during sludge pyrolysis was preferable for recovering sludge P in the form of hydroxylapatite. Moreover, the hydroxylapatite produced with these additives was unstable when the pyrolysis temperature was above 900 °C. The pot experiment demonstrated the feasibility using the sludge-derived pyrochars as P fertilizer for plant growth. Therefore, changing the Ca form and/or Ca/P ratio with the addition of Ca-based additives could be an effective strategy for reclaiming P from SS in the form of hydroxylapatite, and this demonstrates a pathway for global P sustainability by recycling P from P-abundant wastes.


Asunto(s)
Fósforo , Aguas del Alcantarillado , Calcio , Durapatita , Fertilizantes
9.
Bioresour Technol ; 300: 122683, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31901772

RESUMEN

This study explored the effect of two carbon sources on performance and population structure of granular enhanced biological phosphorus removal systems at long-term low temperature by using two sequencing batch reactors, with acetate (SBR-1) and propionate (SBR-2) as carbon sources respectively. Results showed that highly efficient EBPR were successfully achieved, and the average PO43--P and COD removal efficiency of SBR-1 and SBR-2 were 94.2%, 87.1% and 98.2%, 87.0%, respectively. Moreover, the acetate system preferred to utilize intracellular Mg/K-polyP to produce ATP for VFA uptake rather than glycogen. High-throughput sequencing analysis revealed that the abundance of Rhodocyclaceae were 31.7% (SBR-1) and 71.7% (SBR-2), and genus Dechloromonas was enriched to 60.5% with propionate, evidently higher than acetate (1.2%). Furthermore, in addition to oxygen, Dechloromonas could use nitrate as electron acceptors for phosphate uptake. The study further provides support to simultaneous nitrogen and phosphorus removal at low temperature.


Asunto(s)
Carbono , Fósforo , Reactores Biológicos , Nitrógeno , Aguas del Alcantarillado , Temperatura Ambiental , Eliminación de Residuos Líquidos
10.
Water Res ; 171: 115441, 2020 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-31927090

RESUMEN

This study is an analysis of relationships between microalgae (measured as chlorophyll a) and the fecal indicator bacteria enterococci. Microalgae blooms and enterococci exceedances have been occurring in Florida's recreational waterways for years. More recently, this has become a management concern as microalgae blooms have been attributed to potentially toxic cyanobacteria, and enterococci exceedances link to human infection/illness. Since both the microalgal blooms and bacterial exceedances occur in regions that receive managed freshwater releases from Lake Okeechobee, we hypothesized that both the blooms and exceedances are related to excess nutrients from the lake. Two experimental sites, on Lake Okeechobee and the St. Lucie River (downstream of the lake), plus a control site on the Loxahatchee River (which does not receive lake flow) were evaluated. The hypothesis was evaluated through three study components: 1) analysis of available long-term data from local environmental databases, 2) a year-long monthly sampling and analysis of chlorophyll a, enterococci, nutrients, and physical-chemical data, and 3) microcosm experiments with altered water/sediment conditions. Results support the hypothesis that excess nutrients play a role in both chlorophyll a and enterococci levels. For the St. Lucie River, analyses indicate that chlorophyll a correlated significantly with total Kjeldahl nitrogen (TKN) (R2 = 0.30, p = 0.008) and the strongest model for enterococci included nitrate-nitrite, TKN, total phosphorus, orthophosphorus, and turbidity in our long-term analysis (n = 39, R2 = 0.83, p ≤ 0.001). The microcosm results indicated that chlorophyll a and enterococci only persisted for 36 h in water from all sources, and that sediments from Lake Okeechobee may have allowed for sustained levels of chlorophyll a and enterococci levels. Overall similarities were observed in chlorophyll a and enterococci relationships with nutrient concentrations regardless of a Lake Okeechobee connection, as underscored by a study of flow out of the lake and downstream areas. This suggests that both nutrient-rich lake water and untreated surface water runoff contribute to microalgae blooms and enterococci exceedances in southeast Florida.


Asunto(s)
Lagos , Microalgas , Proliferación Celular , Clorofila , Clorofila A , Enterococcus , Monitoreo del Ambiente , Eutrofización , Florida , Nitrógeno , Fósforo
11.
Bioresour Technol ; 301: 122664, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31931334

RESUMEN

This study investigates the recovery of phosphorus from the process water obtained through hydrothermal carbonisation (HTC) of a 'wet' biomass waste, namely spent coffee grounds. HTC was shown to liberate more than 82% of the total phosphorus in the grounds in the form of dissolved ortho-phosphate. Nanofiltration was used to concentrate the inorganic nutrients of the HTC process water, achieving a mass concentration factor of 3.9 times. The natural stoichiometry of phosphorus, magnesium and ammoniacal nitrogen in the nanofiltration retentate was favourable for struvite precipitation. 92.8% of aqueous phosphorus was recovered as struvite through simple pH adjustment, yielding a total phosphorus recovery of 75% from the feedstock spent coffee grounds.


Asunto(s)
Fósforo , Aguas Residuales , Café , Nitrógeno , Fosfatos , Estruvita , Eliminación de Residuos Líquidos
12.
Water Res ; 171: 115479, 2020 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-31935642

RESUMEN

Internal phosphorus (P) mobility is crucially important to overlying water ecosystems, while its spatiotemporal variations and mechanisms remain to be studied, especially in dynamic estuarine sediments. In this study, in situ monthly field sampling and indoor experiments were combined to measure the soluble reactive P (SRP), soluble Fe and diffusive gradients in thin films (DGT)-labile P/S in the overlying water, sediment and porewater in the Jiuxi River Estuary by employing high-resolution dialysis (HR-Peeper), the DGT technique and a MicroRhizon sampler. The consistent tendency between DGT-labile S and P in most seasons indicates that P mobilization was dominated by intense dissimilatory sulfate reduction (DSR), causing high SRP concentrations and active exchange with the overlying water. The circannual cyclical pattern of P is summarized, where in addition to temperature, monthly changes in runoff and tidal range are crucial external factors to control long-term P cycling via changed redox environments and terrigenous materials inputs. The mobile P, Fe and S present higher values during flood tides and lower values during ebb tides in tidal simulation experiments, demonstrating that the short-term cycling of P, Fe and S in intertidal surface sediments is highly redox-sensitive and controlled by tidal processes. The results also reveal that DSR greatly facilitates P mobility and release, while sediment oxidation and the induced enhancement in DIR and Fe cycling can effectively control P immobilization.


Asunto(s)
Fósforo , Contaminantes Químicos del Agua , Ecosistema , Monitoreo del Ambiente , Estuarios , Sedimentos Geológicos , Diálisis Renal
13.
Bioresour Technol ; 301: 122745, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31954968

RESUMEN

Phosphorus (P) release from sludge containing phosphate precipitates (FePs or AlPs) as well as the anaerobic performance with the addition of complexing agents (citric, tartaric and EDTA) during ambient anaerobic fermentation process were investigated. Results showed that citrate addition was the most effective method to enhance P release from inorganic phosphate by chelation and promote volatile fatty acids (VFAs) production simultaneously during anaerobic fermentation. Equimolar citrate addition with chemical precipitates was the optimal dosage. Microbial analysis revealed that EDTA has the strongest inhibitory effect on microbial activity and community structure, while citrate was more effective in enhancing important acidifying microorganisms than tartrate and EDTA. Therefore, citrate addition can be regarded as an alternative and promising method to recover P and carbon source from sludge containing chemical precipitates. These important discoveries will help to enrich P recovery path from sludge produced in the chemical-enhanced P removal treatment processes.


Asunto(s)
Fósforo , Aguas del Alcantarillado , Anaerobiosis , Ácidos Grasos Volátiles , Fermentación
14.
Bioresour Technol ; 301: 122750, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31954969

RESUMEN

The performance of simultaneous carbon (C), nitrogen (N) and phosphorus (P) removal was investigated by altering the cycle times in an anaerobic-aerobic-anoxic sequencing batch reactor (AOA-SBR) system. Results showed that the AOA-SBR system achieved high simultaneous C, N and P removal efficiency with a cycle time of 6 h, with average removal efficiencies for COD, TN, and TP of 96.81%, 96.32% and 94.33%, respectively. The highest anoxic removal rate of NOX-N was 203.44 mg·g-1- MLVSS·d-1. Meanwhile, anaerobic release rate and aerobic, anoxic removal rate of TP reached peak values of 104.31 and 85.81 mg·g-1- MLVSS·d-1, respectively. Microbial community analysis demonstrated that Proteobacteria, Bacteroidetes and Candidatus Saccharibacteria at phylum level and Betaproteobacteria, Gammaproteobacteria, Sphingobacteriia, Deltaproteobacteria and Alphaproteobacteria at the class level benefited AOA-SBR performance. Functional analysis of genes indicated that the metabolic potential related to C, N and P metabolism increased under the optimal cycle time condition.


Asunto(s)
Fósforo , Aguas Residuales , Anaerobiosis , Reactores Biológicos , Carbono , Nitrógeno , Aguas del Alcantarillado , Eliminación de Residuos Líquidos
15.
Bioresour Technol ; 301: 122753, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31982852

RESUMEN

Phosphorus content of the digestate is crucial for evaluating its fertilizer utilization in anaerobic digestion system. The vermiculite containing rich-phosphorus is firstly used as an accelerant in anaerobic batch co-digestion system of aloe peel waste and dairy manure. After introducing vermiculite, the cumulative biogas production (295.14-353.96 mL/g VS), chemical oxygen demand removal rate (45.53%-71.03%), and volatile solid removal rate (50.70%-52.76%) are remarkably higher than those of reference reactor (234.08 mL/g VS, 39.38%, 45.10%). The thermal and fertility analyses manifest the digestates with vermiculite possess superior stability, admirable fertilizer values (5.97%-6.81%), and excellent total phosphorus content (11.44-13.29 g/kg). The improved co-digestion performance can be attributed to the addition of vermiculite. This work introduces a novel approach for improving the performance of anaerobic co-digestion and the fertilizer utilization of digestate in the co-digestion systems.


Asunto(s)
Aloe , Estiércol , Silicatos de Aluminio , Anaerobiosis , Biocombustibles , Reactores Biológicos , Metano , Fósforo
16.
J Environ Manage ; 256: 109981, 2020 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-31989989

RESUMEN

Bauxite residue is a highly alkaline solid waste with poor physical structure which ultimately limits plant growth. Ecological reconstruction is an effective strategy to improve its environmental management, although soil formation process still requires further investigation. Here, an incubation experiment was used to investigate the effects of phosphogypsum and poultry manure, on aggregate size distribution and aggregate-associated exchangeable bases of bauxite residue. Phosphogypsum and poultry manure additions significantly increased the proportion of 2-1 mm residue aggregates and enhanced mean weight diameter (MWD) of residues in the 0-20 cm and 20-40 cm layers, although little effect was evident in the 40-60 cm layer. Phosphogypsum addition reduced pH and EC values to approximately 8.5 and 200 mS/cm in different size aggregates at 0-20 cm. Exchangeable Ca2+ concentration was improved, especially in 0.25-0.05 mm and <0.05 mm aggregates, following amendment additions. The relative contents of katoite and cancrinite in >0.25 mm aggregate fractions were relatively higher, which was consistent with changes in pH. Phosphogypsum and poultry manure changed the microstructure and surrounding pores of residue aggregates, whilst the concentration of Ca on microaggregate surfaces was higher than that on macroaggregates. These findings reveal that application of phosphogypsum and poultry manure directly alter the distribution of exchangeable bases and alkaline indicators within residue aggregates, resulting in aggregate size distribution and microstructure variations.


Asunto(s)
Óxido de Aluminio , Estiércol , Animales , Sulfato de Calcio , Fósforo , Aves de Corral , Suelo
17.
Ying Yong Sheng Tai Xue Bao ; 31(1): 157-164, 2020 Jan.
Artículo en Chino | MEDLINE | ID: mdl-31957392

RESUMEN

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.


Asunto(s)
Fósforo , Suelo , Agricultura , Granjas , Fertilizantes , Estiércol , Nitrógeno , Triticum
18.
Ying Yong Sheng Tai Xue Bao ; 31(1): 282-292, 2020 Jan.
Artículo en Chino | MEDLINE | ID: mdl-31957406

RESUMEN

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.


Asunto(s)
Ecosistema , Agua de Mar , China , Nitrógeno , Nutrientes , Fósforo
19.
Ying Yong Sheng Tai Xue Bao ; 31(1): 333-339, 2020 Jan.
Artículo en Chino | MEDLINE | ID: mdl-31957412

RESUMEN

A large amount of azo dye wastewater is discharged into the environment, with serious risks to ecosystems and human health. Therefore, the development of treatment technology of azo dye wastewater was of practical significance. Photocatalytic methods showed promising application prospects due to easy to implement and effective. In this study, layered black phosphorus nanosheet (LBP) was used as a catalyst through liquid phase exfoliation method. Methyl orange (MO) was employed as a model azo dye to investigate the catalytic mechanism of LBP. The dominant transient species involved in the photocatalytic reaction was probed by quenching and fluorescence probe experiments. Degradation pathways of MO were proposed according to degradation products identified by the liquid chromatography-mass spectrometry. The results showed that degradation rate (kobs) of MO at acidic condition (pH=3.0) or alkaline condition (pH=11.0) was higher than that at neutral condition (pH=7.0). Degradation pathways of MO included that the azo bond was attacked by hydroxyl radicals (·OH) photogenerated by the LBP, and the intermediate products were further oxidized by ·OH to produce N, N-dimethyl-4-(2-p-phenylmethylhydrazine) aniline, 2-(dimethylamino)-5-((4(dimethylamino) phenyl) diazenyl) phenol and N, N-dimethyl-4-nitroaniline.


Asunto(s)
Ecosistema , Fósforo , Compuestos Azo , Aguas Residuales
20.
J Zoo Wildl Med ; 50(4): 927-936, 2020 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-31926525

RESUMEN

Seabirds have been widely used for monitoring the health of the oceans in diverse marine regions. Among low-cost survey strategies, systematic surveys of seabirds beached on coasts have been developed since the 20th century. However, these studies do not always address blood aspects. The assessment of the health status of birds based on the analysis of hematological and plasma chemistry is crucial to evaluate the overall health status profile of live organisms. Here, the authors study the variability of blood parameters by sex, age class, and year of beached Magellanic Penguin during the nonreproductive period in northern Argentina. Of 44 penguins, 77% were categorized as younger juveniles and the rest as older juveniles, and were captured and studied in coastal areas of Buenos Aires Province during the summers of 2017 and 2018. The mean body weight of beached penguins was affected by the age class of the individuals; most of the younger juveniles showed poor condition in terms of body mass (1,761 ± 235 g). No significant differences were observed in body weight between years and sex. Still, there were significant differences between years for alkaline phosphatase (ALP) and creatine phosphokinase (CPK) values. Twelve of the 20 blood parameters analyzed differ significantly with the age class of the beached penguins; younger juveniles were in a state of inanition. Our results may serve as a necessary first step in improving the conservation status of the Magellanic Penguin in nonbreeding grounds of Argentina, and call for a better knowledge of the health status of the species along its annual cycle.


Asunto(s)
Recuento de Eritrocitos/veterinaria , Hematócrito , Recuento de Leucocitos/veterinaria , Estaciones del Año , Spheniscidae/sangre , Envejecimiento , Fosfatasa Alcalina/sangre , Animales , Animales Salvajes , Anticuerpos Heterófilos , Argentina , Glucemia , Proteínas Sanguíneas , Colesterol/sangre , Creatina Quinasa/sangre , Femenino , Hemoglobinas , Recuento de Linfocitos/veterinaria , Masculino , Fósforo/sangre , Transaminasas/sangre , Urea/sangre , Ácido Úrico/sangre
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