Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.365
Filtrar
1.
J Environ Sci (China) ; 113: 322-344, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34963541

RESUMEN

CO2 utilizations are essential to curbing the greenhouse gas effect and managing the environmental pollutant in an energy-efficient and economically-sound manner. This paper seeks to critically analyze these technologies in the context of each other and highlight the most important utilization avenues available thus far. This review will introduce and analyze each major pathway, and discuss the overall applicability, potential extent, and major limitations of each of these pathways to utilizing CO2. This will include the analysis of some previously underreported utilization avenues, including CO2 utilization in industrial filtration and the processing of raw industrial materials such as iron and alumina. The core theme of this paper is to seek to treat CO2 as a commodity instead of a liability.


Asunto(s)
Dióxido de Carbono , Gases de Efecto Invernadero , Dióxido de Carbono/análisis , Efecto Invernadero , Industrias
2.
J Environ Sci (China) ; 111: 380-391, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34949367

RESUMEN

Anaerobic digestion and incineration are widely used sewage sludge (SS) treatment and disposal approaches to recovering energy from SS, but it is difficult to select a suitable technical process from the various technologies. In this study, life-cycle assessments were adopted to compare the energy- and greenhouse gas- (GHG) emission footprints of two sludge-to-energy systems. One system uses a combination of AD with incineration (the AI system), whereas the other was simplified by direct incineration (the DI system). Comparison between three SS feedstocks (VS/TS: 57.61 -73.1 ds.%) revealed that the AI system consistently outperformed the DI system. The results of sensitivity analyses showed that the energy and GHG emission performances were mainly affected by VS content of the SS, AD conversion efficiency, and the energy consumption of sludge drying. Furthermore, the energy and GHG emission credit of the two systems increased remarkably with the increase in the VS content of the SS. For the high-organic-content sludge (VS/TS: 55%-80%), the energy and GHG emission credit of the AI system increase with the increase of AD conversion efficiency. However, for the low organic content sludge (VS/TS: 30%-55%), it has the opposite effect. In terms of energy efficiency and GHG performance, the AI system is a good choice for the treatment of high-organic-content sludge (VS/TS>55%), but DI shows superiority over AI when dealing with low organic content sludge (VS/TS<55%).


Asunto(s)
Gases de Efecto Invernadero , Aguas del Alcantarillado , Desecación , Efecto Invernadero , Incineración
3.
Bioresour Technol ; 344(Pt B): 126270, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34740796

RESUMEN

The effect of organic bulking agents on CO2, NH3, N2O and CH4 emission and related genes was evaluated in 40 days sludge composting with wood chip, wheat straw and rice husk, respectively. The results showed wood chip had the highest C/N of 111.3, total porosity of 93.13% and aeration porosity of 78.98% among three bulking agents. Wheat straw had the highest water-holding porosity of 25.62%, which could be critical factor increasing CH4 production and reducing NH3 emission. Moreover, there was no significant difference in N2O emission rates in three composting systems with three bulking agents. RDA analysis showed a negative correlation between mcrA and NH + 4-N. Nitrate content in raw feedstock was dominant factor limiting N2O yield due to low amoA. The continuous increase of oxidation-reduction potential was significantly positive correlated with pmoA and negative correlation with nirK and norB, which reduced N2O and CH4 production in the curing period.


Asunto(s)
Compostaje , Gases de Efecto Invernadero , Amoníaco/análisis , Gases de Efecto Invernadero/análisis , Metano/análisis , Óxido Nitroso/análisis , Aguas del Alcantarillado , Suelo
5.
Sci Total Environ ; 811: 152357, 2022 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-34921885

RESUMEN

Majority of industries, in order to meet the technological development and consumer demands generate waste. The untreated waste spreads out toxic and harmful substances in the environment which serves as a breeding ground for pathogenic microorganisms thus causing severe health hazards. The three industrial sectors namely food, agriculture, and oil industry are among the primary organic waste producers that affect urban health and economic growth. Conventional treatment generates a significant amount of greenhouse gases which further contributes to global warming. Thus, the use of microbes for utilization of this waste, liberating CO2 offers an indispensable tool. The simultaneous production of value-added products such as bioplastics, biofuels, and biosurfactants increases the economics of the process and contributes to environmental sustainability. This review comprehensively summarized the composition of organic waste generated from the food, agriculture, and oil industry. The linkages between global health hazards of industrial waste and environmental implications have been uncovered. Stare-of-the-art information on their subsequent utilization as a substrate to produce value-added products through bio-routes has been elaborated. The research gaps, economical perspective(s), and future research directions have been identified and discussed to strengthen environmental sustainability.


Asunto(s)
Gases de Efecto Invernadero , Residuos Industriales , Agricultura , Biocombustibles , Salud Global , Residuos Industriales/análisis
6.
Chemosphere ; 286(Pt 2): 131663, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34371357

RESUMEN

In this study, an immobilization method for forming and keeping dominant petroleum degradation bacteria was successfully developed by immobilizing Pseudomonas, Acinetobacter, and Sphingobacterium genus bacteria on wheat bran biochar pyrolyzed at 300, 500, and 700 °C. The removal efficiency indicated that the highest TPHs (total petroleum hydrocarbons) removal rate of BC500-4 B (biochar pyrolyzed at 500 °C with four kinds of petroleum bacteria) was 58.31%, which was higher than that of BC500 (36.91%) and 4 B (43.98%) used alone. The soil properties revealed that the application of biochar increased the content of organic matter, available phosphorus, and available potassium, but decreased pH and ammonium nitrogen content in soil. Bacterial community analysis suggested that the formation of dominant degrading community represented by Acinetobacter played key roles in TPHs removal. The removal rate of alkanes was similar to that of TPHs. Besides, biochar and immobilized material can also mediate greenhouse gas emission while removing petroleum, biochar used alone and immobilized all could improve CO2 emission, but decrease N2O emission and had no significant impact on CH4 emission. Furthermore, it was the first time to found the addition of Acinetobacter genus bacteria can accelerate the process of forming a dominant degrading community in wheat bran biochar consortium. This study focused on controlling greenhouse gas emission which provides a wider application of combining biochar and bacteria in petroleum soil remediation.


Asunto(s)
Gases de Efecto Invernadero , Petróleo , Contaminantes del Suelo , Álcalis , Bacterias , Biodegradación Ambiental , Carbón Orgánico , Fibras de la Dieta , Gases de Efecto Invernadero/análisis , Hidrocarburos , Petróleo/análisis , Suelo , Microbiología del Suelo , Contaminantes del Suelo/análisis
7.
Environ Res ; 203: 111879, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34390716

RESUMEN

To mitigate greenhouse gas (GHG) emissions, different strategies have been proposed, including application of dolomite, crop straw and biochar, thus contributing to cope with the increasing global warming affecting the planet. In the current study, pristine wheat straw biochar (WBC) and magnesium (MgCl2.6H2O) modified wheat straw biochar (MWBC) were used. Treatments included control (CK), two WBC dosages (1% and 2.5%), and two MWBC doses (1% and 2.5%). After 90 days of incubation, WBC and MWBC improved the soil physiochemical properties, being more pronounced with increasing rates of biochar. MWBC2.5 significantly decreased microbial biomass carbon (MBC), while microbial biomass nitrogen (MBN) increased when both biochar materials (WBC1 and MWBC1) were applied at low rate. Compared to control soil, Urease and Alkaline phosphatase activities increased with the increasing rate of WBC and MWBC. The activities of dehydrogenase and ß-glucosidase decreased with the WBC and MWBC application, compared to CK. The fluxes of all the three GHGs evaluated (CO2, CH4 and N2O) decreased with time for both biochar amendments, while cumulative emission of CO2 increased by 58% and 45% for WBC, and by 54% and 41% for MWBC, as compared to CK. The N2O cumulative emissions decreased by 18 and 34% for WBC, and by 25 and 41% for MWBC, compared to CK, whereas cumulative methane emission showed non-significant differences among all treatments. These findings indicate that Mg-modified wheat straw biochar would be an appropriate management strategy aiding to reduce GHG emissions and improving the physiochemical properties of affected soils, and specifically of the red dry land soil investigated in the current work.


Asunto(s)
Gases de Efecto Invernadero , Agricultura , Carbón Orgánico , Magnesio , Óxido Nitroso , Suelo , Triticum
8.
Sci Total Environ ; 806(Pt 2): 150465, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34582858

RESUMEN

Biochar is a promising alternative to agricultural productivity and climate change mitigation. However, quantitative data are needed to better understand the productivity and greenhouse gas (GHG) emissions from agricultural fields amended with biochar. To assess the impacts of the four biochars on soil properties, forage productivity, and GHG emissions, a 1-year field experiment was conducted in a Humic Haploxerands (Andisol). Three manure-derived biochars and one wood residue biochar (all pyrolyzed at 550 °C) were applied at rates of 1% (equivalent to 11 t ha-1) in two parallel and independent experiments. The changes in (i) soil chemical properties and yield of Sorghum sudangrass (S. bicolor×S. bicolor var. Sudanese) and (ii) soil CO2 and N2O emissions were monitored. Two controls, with and without NPK, were included. The added amendments produced from residues of poultry and pig systems increased soil pH by 0.73 and 0.19 units, respectively. Increased sorghum yield were associated with fertilizer and the liming potential of the added biochar. Soil total carbon (TC) increased with the addition of different biochars, especially during the wood biochar treatment. Biochar application, regardless of the feedstock, had no significant impact on the cumulative soil CO2 emitted after a year. Soil N2O fluxes decreased (23%-50%) in treatments containing biochars with low mineral N contents and high C stability (i.e., low H:OC and Cox:TC ratios). NPK treatment resulted in the highest N2O emissions. Wood residue-derived biochar has a great potential in mitigating climate change, reducing soil N2O emissions, and promoting soil C storage. Manure-derived biochars could be instrumental in circular economy livestock systems, where pyrolyzed animal manure can satisfy the demand for nutrients and/or liming of Andisols under sustainable forage models.


Asunto(s)
Gases de Efecto Invernadero , Animales , Carbón Orgánico , Óxido Nitroso/análisis , Suelo , Porcinos
9.
Sci Total Environ ; 806(Pt 2): 150528, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34582870

RESUMEN

Agriculture constitutes a quarter and more than a third of Denmark's global greenhouses gas (GHG) emissions and natural resource consumption, respectively. This paper aims to estimate the potential to lower Denmark's global food-related GHG, blue water and land footprints using the most recent version of a hybrid global multi-regional input-output (MRIO) database, EXIOBASE of the reference year, 2011. Specifically, we apply the 'what if' scenario-based MRIO approach to EXIOBASE and quantify the impact of increased livestock feed efficiency (FE), dietary changes, food loss and waste (FLW) reduction/prevention and food waste treatment scenarios on Denmark's global food-related GHG and resource footprints. We obtain modest reductions in Denmark's global food-related GHG, blue water and cropland footprint from the combination of livestock FE improvements and FLW reduction; 61 kt CO2e, 2 Mm3 and 30 kha, respectively. In contrast, dietary change towards no/less meat and dairy diets embodies the most significant reductions potential for Denmark's total global food-related GHG, blue water, croplands and grassland footprint by up to 34% (3.63 Mt. CO2e), 8% (90 Mm3), 23% (371 kha) and 78% (386 kha) respectively. A key policy priority should therefore be the nudging of Danish consumers towards sustainable diets. Also, this study's findings emphasise that FLW prevention remains the most effective food waste-related climate mitigation and resource efficiency strategy despite the benefits of food waste valorisation.


Asunto(s)
Gases de Efecto Invernadero , Eliminación de Residuos , Conservación de los Recursos Naturales , Efecto Invernadero , Carne
10.
Sci Total Environ ; 806(Pt 2): 150695, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34597577

RESUMEN

Household greenhouse-gas footprints (HGFs) are an important source of global emissions but can vary widely between urban and rural areas. These differences are important during the ongoing rapid, global, urbanization process. We provide a global overview of HGFs considering this urban-rural divide. We include 16 global regions, representing 80% of HGFs and analyze the drivers of urban and rural HGFs between 2005 and 2015. We do this by linking multi-regional input-output (MRIO) tables with household consumption surveys (HCSs) from 43 regions. Urban HGFs from high-income regions continue to dominate, at 75% of total HGFs over 2010-2015. However, we find a significant increase of rural HGFs (at 1% yr-1), reflecting a convergent trend between urban and rural HGFs. High-income regions were responsible for the majority of urban HGFs (USA: 27.8% and EU: 18.7% in 2015), primarily from transport and services, while rural HGFs were predominately driven in emerging regions (China: 24% and India: 21.8% in 2015) mainly driven by food and housing. We find that improving emission intensities do not offset the increase in HGFs from increasing consumption and population during the period. A broad transition of expenditure from food to housing in rural areas and to transport in urban areas highlights the importance of reducing the emission intensities of food, housing, and transportation. Counterintuitively, urbanization increased HGFs in emerging regions, resulting in a >1% increase in China, Indonesia, India and Mexico over the period, due to large migrations of people moving from rural to urban areas.


Asunto(s)
Gases de Efecto Invernadero , China , Composición Familiar , Humanos , Población Rural , Población Urbana , Urbanización
11.
Sci Total Environ ; 806(Pt 3): 150608, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34606854

RESUMEN

Nitrous oxide (N2O) emissions from dairy-grazing pastures can be dominated by large emissions from small areas ('hotspots') frequently used by grazing dairy cattle (i.e., water troughs and gateways). N2O emissions from these hotspots are quantified by investigating whether N2O emissions and emission factors (% of applied N emitted as N2O, EF3) from potential hotspots are different from non-hotspots. To better characterise N2O emissions from hotspots and non-hotspots of farms to understand their contributions to national agricultural greenhouse gas inventory calculations, a series of measurements were conducted during winter and spring on two NZ typical dairy farms with contrasting soil drainage (poorly versus well drained). Before measurements were taken, the soils either received a cow urine application or remained untreated. The results showed that changes in water-filled pore space (WFPS) and mineral N around water troughs and gateways, due to additional stock movements and disproportionate excreta-N deposition during previous grazing events, affected both background and total N2O emissions. But there was little impact on EF3 values (calculated using IPCC guidelines) from deposited urine between hotspot and pasture areas. These results suggest the same EF3 values can be used for both to calculate emissions from urine deposited on grazed pastures. However, these results raise concerns about higher background emission in hotspots subtracted from measured emissions from urine-N deposition in calculating EF3 values and discounting the effects of disproportionate N inputs in intensive agriculture on increased background emissions (legacy effect). This IPCC inventory method does not account for the legacy effect of N loading prior to the measurements which may underestimate the emissions. Thus, an allowance for higher hotspot background emissions could be included in the Inventory to accurately estimate total emissions from agriculture.


Asunto(s)
Gases de Efecto Invernadero , Óxido Nitroso , Agricultura , Animales , Bovinos , Granjas , Femenino , Gases de Efecto Invernadero/análisis , Óxido Nitroso/análisis , Suelo
12.
Sci Total Environ ; 807(Pt 1): 150700, 2022 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-34606858

RESUMEN

The interconnection of urbanization trends and environmental pressures, are due to the rising demand for resource consumption, waste production and greenhouses gas emissions. Taking into consideration the massive reduction of natural resources, the deprivation of the life quality and the climate change, the scientific community indicates the necessity to emphasis and understand the relationship between cities and the environment as a dynamic concept. Consequently, cities are facing the challenge to implement alternative strategies towards more sustainable management of urban resources. This research aims to shed light on the concept of urban metabolism, the methods that are been used to gauge urban metabolism (i.e Emergy Analysis, Material Flow Analysis, Ecological Footprint etc.), as well as the assessment of the proposed methodologies through SWOT analysis and Analytical Hierocracy Process, considering multi-criteria analysis and how those reflect to Circular Economy and European Green Deal Strategy. The results showed that, the existing methodologies needs refreshment to cover the needs for the cities of tomorrow and a new hybrid approach which will include new set of Key Performed Indicators is essential. Furthermore, the results could serve as a beneficial reference point for policy makers, consultants, rural developers as the new hybrid approach can be used to measure and assess the level of metabolism in one area in order to prevent future expansion.


Asunto(s)
Gases de Efecto Invernadero , Urbanización , Ciudades , Conservación de los Recursos Naturales
13.
Chemosphere ; 288(Pt 1): 132444, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34626658

RESUMEN

Volatile fatty acids (VFAs) are the building blocks of the chemical industry, and they are the primary contributors to the planet's organic carbon cycle. VFA production from fossil fuels (mostly petroleum) is unsustainable, pollutes the environment, and generates greenhouse gases. As a result of these issues, there is a pressing need to develop alternate sources for the long-term generation of VFAs via anaerobic digestion. The accessible feedstocks for its sustainable production, as well as the influencing parameters, are discussed in this review. The use of VFAs as a raw material to make a variety of consumer products is reviewed in order to find a solution. It also bridges the gap between traditional and advanced VFA production and utilization methods from a variety of solid and liquid waste sources for economical stability.


Asunto(s)
Ácidos Grasos Volátiles , Gases de Efecto Invernadero , Anaerobiosis , Reactores Biológicos , Fermentación , Concentración de Iones de Hidrógeno
14.
J Environ Manage ; 302(Pt A): 113960, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34700076

RESUMEN

The rapid specialization of livestock production in China has contributed to spatially decoupled crop and livestock production, leading to various environmental pollution issues. Some regional agro-environmental policies have recently promoted the coupling of specialized crop and livestock farms through cooperation. However, the environmental and economic performances of such cooperation remain unclear. This study investigated multiple environmental footprints of two contrasting production systems: cooperative crop-livestock systems (CCLS) and decoupled specialized livestock systems (DSLS), using survey data of 87 ruminant farms in Northwest China. Results show that farms in CCLS had lower net greenhouse gas (GHG) emissions (12-29%), lower reactive nitrogen (Nr) emissions (21-40%), lower phosphorus footprints (PF) (41-54%), and used less cropland (24-31%) per kg animal product, compared to those in DSLS. The large differences in GHG emissions between the two systems were mainly related to enteric fermentation and resource production (used for feed production). The differences in Nr emissions and PF were mainly related to manure management. Net profits per kg animal product were higher in CCLS (13-35%) than in DSLS, and most profits originated from lower purchasing costs of feed and young livestock. Net profits and environmental footprints were negatively correlated, suggesting an environmental and economic win-win situation for CCLS. The possible obstacles to recoupling specialized crop and livestock farms through cooperation have been discussed, including farm size, contract stability, and local policies. Our study provides science-based evidence to support policymakers and specialized farms to close nutrient loops between crop and livestock production sectors through regional cooperation.


Asunto(s)
Gases de Efecto Invernadero , Ganado , Animales , Granjas , Estiércol , Nitrógeno
15.
J Environ Manage ; 302(Pt A): 113975, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34700081

RESUMEN

Although plastic is one of the most commonly used materials in our everyday life, the current linear economy ('produce, use and dispose') engenders high risks to human health in relation to greenhouse gas (GHG) emissions and environmental pollution. As a response to these challenges, the circular plastic economy is gaining momentum, where the goal is to reduce, reuse and recycle all plastic. The transition to the circular economy should be made across the entire plastics value chain in order to ensure circular design, production, use and waste management. This study examines the current scientific literature in relation to the entire value chain of plastics. This aim of the article is to provide an overview of the existing research (and highlight research gaps) associated with the transition of plastic use to a circular model. The literature was divided into the following categories: 1) design; 2) production; 3) use; 4) end-of-life; and 5) value chain. A high proportion of the literature was found to address the end-of-life phase, suggesting that the other phases are currently neglected. The results have implications that are applicable to multiple phases; in particular, contamination of waste streams and composite materials places significant limitations on the opportunity to recycle and reuse plastic in new products. This calls for changes in the whole value chain, and for trans-sectorial collaboration to ensure systemic transparency. Therefore, future research should take a holistic approach to the transition to circular through careful mapping of implications, stakeholder involvement and collaboration.


Asunto(s)
Gases de Efecto Invernadero , Administración de Residuos , Humanos , Plásticos , Reciclaje
16.
J Environ Manage ; 302(Pt A): 113955, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34700088

RESUMEN

Agroforestry has a potentially important role in helping agriculture address both the climate and biodiversity crises. It provides a means of producing additional marketable goods from agricultural land and enhancing biodiversity at the same time as increasing carbon sequestration and, in silvo-pastural systems, reducing carbon emissions if livestock stocking rates are reduced. However, the uptake of agroforestry in the UK has been limited. This paper adopts Real Options techniques to explore how the decision to adopt agroforestry is influenced by the relative levels of returns from agriculture, forestry and the price of carbon under the scenario where there are financial penalties from livestock Greenhouse Gas (GHG) emissions, financial benefits from carbon sequestration in trees and reversibility in land use decisions. The results are compared to the equivalent findings from a Land Equivalent Value capital budgeting approach to agroforestry adoption. Analysis is based on data from a case study upland livestock farm in Scotland, comparing the impacts of introducing agroforestry into the hill sheep enterprise or the low ground cattle and sheep enterprise. The results suggest that the adoption of agroforestry is far less likely than would be suggested by standard budgeting approaches, especially in more extensive upland enterprises (hill area) where sequestration benefits are low relative to more productive farmland areas (low ground area). Upfront support payments are shown to increase the likelihood of agroforestry adoption. They also have the effect of reducing the rotation length of forestry in such systems.


Asunto(s)
Agricultura Forestal , Gases de Efecto Invernadero , Agricultura , Animales , Secuestro de Carbono , Bovinos , Gases de Efecto Invernadero/análisis , Ovinos , Árboles
17.
Sci Total Environ ; 806(Pt 3): 151260, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34715224

RESUMEN

Sulfate (SO42-) concentrations in eutrophic lakes are continuously increasing; however, the effect of increasing SO42- concentrations on organic carbon mineralization, especially the greenhouse gas emissions of sediments, remains unclear. Here, we constructed a series of microcosms with initial SO42- concentrations of 0, 30, 60, 90, 120, 150, and 180 mg/L to study the effects of increased SO42- concentrations, coupled with cyanobacterial blooms, on organic carbon mineralization in Lake Taihu. Cyanobacterial blooms promoted sulfate reduction and released a large amount of inorganic carbon. The SO42- concentrations in cyanobacteria treatments significantly decreased and eventually reached close to 0. As the initial SO42- concentration increased, the sulfate reduction rates significantly increased, with maximum values of 9.39, 9.44, 28.02, 30.89, 39.68, and 54.28 mg/L∙d for 30, 60, 90, 120, 150, and 180 mg/L SO42-, respectively. The total organic carbon content in sediments (51.16-52.70 g/kg) decreased with the initial SO42- concentration (R2 = 0.97), and the total inorganic carbon content in overlying water (159.97-182.73 mg/L) showed the opposite pattern (R2 = 0.91). The initial SO42- concentration was positively correlated with carbon dioxide (CO2) emissions (R2 = 0.68) and negatively correlated with methane (CH4) emissions (R2 = 0.96). The highest CO2 concentration and lowest CH4 concentration in the 180 mg/L SO42- treatment were 1688.78 and 1903 µmol/L, respectively. These biogeochemical processes were related to competition for organic carbon sources between sulfate reduction bacteria (SRB) and methane production archaea (MPA) in sediments. The abundance of SRB was positively correlated with the initial SO42- concentration and ranged from 6.65 × 107 to 2.98 × 108 copies/g; the abundance of MPA showed the opposite pattern and ranged from 1.99 × 108 to 3.35 × 108copies/g. These findings enhance our understanding of the effect of increasing SO42- concentrations on organic carbon mineralization and could enhance the accuracy of assessments of greenhouse gas emissions in eutrophic lakes.


Asunto(s)
Cianobacterias , Gases de Efecto Invernadero , Dióxido de Carbono , Sedimentos Geológicos , Lagos/análisis , Metano/análisis , Sulfatos/análisis
18.
J Environ Manage ; 302(Pt A): 113971, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34715612

RESUMEN

The present work discusses the problems and management options of beach wrack and dredged sediments. Beach wrack and dredged sediments near the shores have affected the coastal ecosystem, badly. The piles of beach wrack residues might be a significant emitter of greenhouse gases (GHGs) and dredged sediment is a substantial source of heavy metals and other pollutants. The recovery of valuable resources such as metals and nutrients from these so-called "wastes" is a sustainable strategy to enhance the resilience of the coastal ecosystem and management. The beach wrack meadows can be a potential source for green energy production. Even the demand for biodegradable polymers can be supplied by utilizing the waste beach wracks. The residues of beach wrack species like Posidonia oceanica, Zostera marina, Ulva spc. and Enhalus acorodies can be very beneficial species in terms of economic growth. Red algae have been the most favored and efficient candidate for methane yield. In case of dredged sediment, dewatering of sediment is an essential step for successful resource extraction. Although, extraction methods are almost similar to that applied for soil treatment, which includes pretreatment, physical partitioning, washing, thermal treatment, biological extraction, and immobilization. The fractionation study can be a beneficial tool for determining the metal species present in the sediment. Immobilization techniques are successful but continuous monitoring is required. The vitrification technique is highly effective but very expensive. Thermal treatment is useful for volatile metals such as mercury (Hg), but costs are high. Biological extractions are comparatively cheap but time-consuming. Henceforth, very few extraction methods are available for sediment and required further advancement in this field.


Asunto(s)
Gases de Efecto Invernadero , Metales Pesados , Ecosistema , Monitoreo del Ambiente , Sedimentos Geológicos , Metales Pesados/análisis , Suelo
19.
Sci Total Environ ; 806(Pt 3): 151256, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34717998

RESUMEN

Applying biochar in association with crop residues might optimize costs and effectiveness in the reclamation of saline soils. Here, we explored the potential effects of biochar in association with crop residue amendments on soil greenhouse gas (GHG) emissions, and microbial communities. Previously, we found that soil N2O emission significantly increased with increasing salinity levels followed by cotton straw addition. In the present study, microcosm experiments were performed to investigate the interaction of salinity (0 and 1.2% salt) with the aging of biochar following soil amendments over an incubation period of 80 days. The results indicated that N2O emissions were approximately 5-10 times higher in saline soils than in non-saline soils, and the cumulative N2O emissions following two straw amendments treatment were the highest of all the treatments. Salinity increased the contribution of nitrification to soil N2O emissions stimulated by the cotton straw amendments, and aged biochar performed better in decreasing soil N2O emissions in saline soils than in non-saline soils. In addition, aged biochar increased soil C mineralization and CO2 emissions under saline conditions. Soil CO2 and N2O emissions were affected by both soil abiotic and biotic factors under non-saline and saline conditions. Moreover, much more specific but fewer microbial groups survived and utilized crop residues under saline than non-saline conditions, and aged biochar decreased salt stress in soil microorganisms. These findings indicated that aged biochar and crop residues together would be an optimal way to address soil C storage and mitigate N2O emissions under saline conditions.


Asunto(s)
Gases de Efecto Invernadero , Suelo , Agricultura , Carbón Orgánico , Fertilizantes , Gases de Efecto Invernadero/análisis , Laboratorios , Óxido Nitroso/análisis
20.
Sci Total Environ ; 806(Pt 3): 151337, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34743889

RESUMEN

Applying organic amendments to soil can increase soil organic carbon (SOC) storage and reduce greenhouse gas (GHG) emissions generated by agriculture, helping to mitigate climate change. However, it is necessary to determine which type of amendment produces the most desirable results. We conducted a 3-y field study comparing one-time addition of manure compost and its biochar derivative to a control to assess their effects on SOC and GHG emissions at ten annually cropped sites in central Alberta, Canada. Manure compost and biochar were applied at equivalent carbon rates (7 Mg ha-1) and tilled into the surface 10 cm of soil. Two years post-treatment, biochar addition increased surface (0-10 cm) SOC by 12 and 10 Mg ha-1 relative to the control and manure addition, respectively. Therefore, biochar addition led to the sequestration of SOC at a rate of 2.5 Mg ha-1 y-1 relative to the control. No treatment effect on deeper (10-100 cm) or cumulative SOC was found. In 2018 and 2019, manure addition increased cumulative GHG (sum of CO2, CH4, and N2O) emissions by 33%, on average, due to greater CO2 emissions relative to both the control and biochar addition. In contrast, in 2020, biochar addition reduced cumulative GHG emissions by an average of 21% due to lower CO2 emissions relative to both the control and manure addition. Our study shows that the application of biochar, rather than its manure compost feedstock, increased surface SOC sequestration and had either no effect on (first two years) or reduced GHG emissions (year three) relative to the control. We recommend that policy and carbon sequestration initiatives focus on optimizing biochar production-application systems to fully realize the potential of biochar application as a viable climate change mitigation practice in agriculture.


Asunto(s)
Gases de Efecto Invernadero , Agricultura , Alberta , Carbono , Carbón Orgánico , Productos Agrícolas , Estiércol/análisis , Óxido Nitroso/análisis , Suelo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...