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1.
Chemosphere ; 365: 143337, 2024 Sep 12.
Artículo en Inglés | MEDLINE | ID: mdl-39277043

RESUMEN

Legacy waste dumpsites have been a significant environmental concern in India for many years. These dumpsites are characterized by the uncontrolled disposal of Municipal Solid Waste (MSW) and have led to various types of pollution and disease outbreaks. As India faces the challenges of rapid urbanization and increased waste generation and with over 3000 legacy waste dumpsites in the country, the need to address these legacy waste dumpsites has become paramount. As we continue to struggle extensively for waste management as well as space, landfill mining has been recognized as a promising way of recovering resources in our country by employing various technological and engineering advancements to extract valuable materials and energy from legacy waste streams. Unlike existing waste management approaches, this review explores the application of a novel Recovery Potential Index (RPI) for legacy waste dumpsites in India, which evaluates the feasibility of waste treatment facilities based on waste compositions and recovered material quantities. Depending on the RPI, recovered fine fractions can be sold as city compost or used as fill material, while recyclable, combustible, and inert fractions could be directed towards appropriate recycling or landfill uses. Unscientific and uncontrolled landfill mining practices could lead to unanticipated impacts on the nearby environment in the form of heavy contamination, thereby presenting this practice as a challenge in addition to the immense opportunities it provides.

2.
Sci Total Environ ; : 176428, 2024 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-39312979

RESUMEN

Sewage sludge phosphorus (P) recovery presents opportunities to sustainably recycle P from cities to agriculture and alleviate global P scarcity. However, limited research explores sustainable recovery targets considering spatial-temporal variations in sludge generation and implications based on city-level local P demand. This study analyzed sludge production over 2009-2021 across 130 cities in China's Yangtze River Zone, which increased by almost 35 % from 2009 to 2021. Per capita gross domestic product (GDP), influent chemical oxygen demand (COD), and per capita drainage infrastructure were identified as main significant influencing factors. City-level analysis revealed pronounced spatial-temporal disparities, with yearly sludge generation spanning five orders of magnitude (62-5.4 × 105 t/a). An indicator, "Potential of P recovery to local P demand", was defined, indicating the average city-level P recycle contribution increased from 5.3 % to 18.9 % during 2009-2021. A novel frame paradigm based on supply-demand characteristics classified cities into "P recycling supply cities" with surplus recoverable P versus "P recycling self-sufficient cities". City-specific dynamics and possibilities of broader "city clusters" to match supply and demand should be considered for policies implement. Recovering P from livestock manure and kitchen waste alongside sludge can further strengthen urban P cycles. This study provides novel city-scale analysis and strategic considerations for regional sludge P recycling policies in China and beyond.

3.
Waste Manag Res ; : 734242X231219654, 2024 Jan 17.
Artículo en Inglés | MEDLINE | ID: mdl-38233370

RESUMEN

In recent years, the concept of landfill mining has gained a lot of traction in India, and tonnes of plastic waste is being excavated. The present shift towards a circular economy necessitates to explore the use of excavated plastic waste as a source of valuable materials and energy. However, the physicochemical characteristics of plastic waste change due to the degradation and weathering process in landfills, making its valorization difficult. The current study investigates the change in physicochemical characteristics of plastic waste with age from an Indian dumpsite to identify the potential valorization options. In addition, a material and energy flow analysis was performed considering incineration treatment of plastic waste. The plastic waste ranged between 3.6 and 21% in the dumpsite and has almost doubled in recent decades, owing to the increase in plastic waste generation in India. Polyethylene (high- and low-density) accounted for approximately 66% of the excavated plastic waste and had a lot of adhered surface impurities. Mechanical pre-treatment using a shredder was effective in the removal of the adhered impurities with a recovery rate of 50-70% for polyethylene and a higher recovery of 70-90% for other types of plastic. Changes in the surface morphology of plastic waste with aging were observed through Scanning Electron Microscopy. The Fourier Transform Infrared Spectroscopy results confirmed low degradation levels for aged plastic waste, which is also confirmed through the high level of oxygen detected. The material and energy flow analysis revealed that incinerating one tonne of excavated plastic waste could produce approximately 1410 kWh of electricity.

4.
Sci Total Environ ; 912: 169518, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38142003

RESUMEN

To support smart cities in terms of waste management and bioenergy recovery, the co-digestion of sewage sludge (SeS) and food waste (FW) was conducted by the anaerobic membrane bioreactor (AnMBR) under mesophilic and thermophilic conditions in this study. The biogas production rate of the thermophilic AnMBR (ThAnMBR) at the SeS to FW ratio of 0:100, 75:25, 50:50 and 100:0 was 2.84 ± 0.21, 2.51 ± 0.26, 1.54 ± 0.26 and 1.31 ± 0.08 L-biogas/L/d, inconspicuous compared with that of the mesophilic AnMBR (MeAnMBR) at 3.00 ± 0.25, 2.46 ± 0.30, 1.63 ± 0.23 and 1.30 ± 0.17 L-biogas/L/d, respectively. The higher hydrolysis ratio and the poorer rejection efficiencies of the membrane under thermophilic conditions, resulting that the permeate COD, carbohydrate and protein of the ThAnMBR was higher than that of the MeAnMBR. The lost COD that might be converted into biogas was discharged with the permeate in the ThAnMBR, which was partly responsible for the inconspicuous methanogenic performance. Furthermore, the results of energy recovery potential assessment showed that the energy return on investment (EROI) of the MeAnMBR was 4.54, 3.81, 2.69 and 2.22 at the four SeS ratios, which was higher than that of the ThAnMBR at 3.29, 2.97, 2.02 and 1.80, respectively, indicating the advantage of the MeAnMBR over the ThAnMBR in energy recovery potential. The outcomes of this study will help to choose a more favorable temperature to co-digest SeS and FW to support the construction of smart cities.


Asunto(s)
Eliminación de Residuos , Aguas del Alcantarillado , Eliminación de Residuos/métodos , Anaerobiosis , Alimento Perdido y Desperdiciado , Alimentos , Biocombustibles , Metano/análisis , Reactores Biológicos , Digestión
5.
Cureus ; 15(5): e39659, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37388589

RESUMEN

Metatarsal bone fractures are one of the most frequent foot injuries, especially after motor vehicle accidents in children. This case report briefly demonstrated a rare instance of pediatric all-metatarsal fractures of the left foot in an adolescent patient with polytrauma after a motorcycle accident. This case report illustrated the surgical procedure's potential for healing pediatric foot fractures in teenage patients after polytrauma. In the examination of a 16-year-old male patient brought to the emergency department after a motorcycle accident, we detected a right foot third finger proximal phalanx open fracture, right foot fourth finger proximal phalanx fracture, left foot first metatarsal proximal fracture, left foot second, third, fourth, and fifth metatarsal distal fractures, left foot cuboid, and navicular bone fractures. The patient's left foot's metatarsals were all fractured. The posterolateral wall fracture of the patient's right maxilla was also detected. All metatarsals were displaced, the second metatarsal paired with the third, etc., and because of this displacement, the closed reduction was impossible, and even the open reduction was challenging to reach the correct pairs. We performed closed reduction and fixation with Kirschner wire for the left foot's first metatarsal fracture and open reduction and fixation with Kirschner wire for the left foot's second, third, and fourth metatarsal distal fractures. We also performed closed reduction and fixation with Kirschner wire for the right foot third and fourth proximal phalanx fractures. We observed callus formation in the sixth week and removed the patient's K-wires. At eight weeks, the X-ray demonstrated the correct alignment of all metatarsals. The proper alignment of all metatarsals and the full range of motion of all foot and ankle joints were achieved with early surgical intervention, open reduction, and timely rehabilitation. This case also emphasizes the importance of open reduction in such irreducible and heavily displaced cases of multiple fractures as all-metatarsal fractures and contributes to the literature with a specific treatment modality in the case of all-metatarsal fractures lacking in the literature.

6.
J Environ Manage ; 342: 118154, 2023 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-37207462

RESUMEN

Macrophytes are of key importance to the structure and ecological services of shallow lakes and are sensitive to anthropogenic and natural perturbations. Ongoing eutrophication and hydrological regime change affect macrophytes through changes in water transparency and water level, which lead to a dramatic decrease in bottom light availability. Here an integrated dataset (2005-2021) of multiple environmental factors is used to demonstrate the driving forces and recovery potential of the macrophyte decline in East Taihu Lake by using a critical indicator, which is the ratio of the Secchi disk depth to the water depth (SD/WD). The macrophyte distribution area showed a remarkable decrease from 136.1 ± 9.7 km2 (2005-2014) to 66.1 ± 6.5 km2 (2015-2021). The macrophyte coverage in the lake and in the buffer zone decreased by 51.4% and 82.8%, respectively. The structural equation model and correlation analysis showed that the distribution and coverage of macrophytes decreased with the decrease in the SD/WD over time. Moreover, an extensive hydrological regime change, which caused a sharp decrease in SD and an increase in the water level, is likely to be the driving force that brought about the decline of macrophytes in this lake. The proposed recovery potential model shows that the SD/WD has been low in recent years (2015-2021), and that this SD/WD cannot ensure the growth of submerged macrophytes and is unlikely to ensure the growth of floating-leaved macrophytes, especially in the buffer zone. The approach developed in the present study provides a basis for the assessment of macrophyte recovery potential and the management of ecosystems in shallow lakes that suffer from macrophyte loss.


Asunto(s)
Ecosistema , Lagos , Agua , Eutrofización , China
7.
Ecotoxicol Environ Saf ; 257: 114936, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-37099963

RESUMEN

Numerous anthropogenic stressors, such as habitat alteration and nutrient enrichment, affect coastal and marine ecosystems around the globe. An additional threat to these ecosystems is accidental oil pollution. The proactive planning of efficient oil spill response actions requires a firm understanding of the spatiotemporal distribution of ecological coastal values at stake, and how these values can be protected in case of an oil spill. In this paper, literature and expert knowledge regarding the life history attributes of coastal and marine species were used to build a sensitivity index to assess the differences in the potential of species and habitat types to be safeguarded from oil. The developed index prioritizes sensitive species and habitat types based on 1) their conservation value, 2) the oil-induced loss and recovery potential, and 3) the effectiveness of oil retention booms and protection sheets to safeguard these entities. The final sensitivity index compares the predicted difference in the state of populations and habitat types five years after an oil spill with and without protective actions. The higher the difference, the more worthwhile the management actions are. Hence, compared to other oil spill sensitivity and vulnerability indexes presented in the literature, the developed index considers the usefulness of protective measures explicitly. We apply the developed index to a case study area in the Northern Baltic Sea to demonstrate the approach. It is noteworthy that the developed index is applicable to other areas as well, as the approach is based on the biological attributes of species and habitat types instead of individual occurrences.


Asunto(s)
Contaminación por Petróleo , Ecosistema , Accidentes
8.
Waste Manag Res ; 41(2): 407-417, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36134679

RESUMEN

In this study, two most common biological waste to energy conversion techniques have been analysed and compared on the basis of methane generation and energy recovery potential. The biogas generation potential has been estimated using anaerobic co-digestion experiment. The main substrate used for this study was food waste, while cow dung and anaerobic digester sludge were used as co-digestion substrates. Food waste was used because of its maximum composition (36% of total wastes) in the study area (Dhanbad city, India) with high biogas generation potential. Cow dung acted as a natural buffer, while anaerobic digester sludge was a source of active inoculum. Based on the maximum biogas yield of 402 mL g-1 VS and annual food waste generation rate in the study area, the energy recovery potential using anaerobic digestion was estimated to be 6.59 × 106 kWh year-1. Presently, the wastes in the mixed form are being dumped on a large abandoned land with an approximate area of 93 ha in the outskirts of Dhanbad city in an uncontrolled manner. The annual landfill gas generation from the existing landfill has been estimated using Landfill Gas Emissions Model (LandGEM) based on the waste characteristics, anticipated landfill life and other region-specific parameters of the present study area. The maximum electrical energy recovery potential of 44.62 × 105 kWh from landfill gas has been estimated for the year 2041. Although, the results are based on the waste generation and characteristics of Dhanbad city, the comparison methodology can be applied to other cities.


Asunto(s)
Eliminación de Residuos , Residuos Sólidos , Residuos Sólidos/análisis , Eliminación de Residuos/métodos , Anaerobiosis , Aguas del Alcantarillado/química , Metano , Biocombustibles/análisis , Alimentos , Reactores Biológicos
9.
J Environ Manage ; 318: 115624, 2022 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-35772269

RESUMEN

Centralized biological treatments, i.e., anaerobic digestion (AD) and in-vessel composting (IVC), were supposed to be the promising processes for the disposal of food waste (FW) after source separation, while the systematic benefits were unclear for FW with high water content, salt and oil and thus influenced the selection by the local decision-makers. In this study, two large-scale working AD and IVC plants were compared for environmental impacts, nutrient recovery and economic benefits. For unit amount of FW, 89.26 kg CO2-eq was released in IVC mainly due to 47.89 kWh electricity consumption, and 57.02 kg CO2-eq was produced in AD. With the application of compost and energy recovery, 26.88 and 93.55 kg CO2-eq savings were obtained in IVC and AD, respectively. NH3 emissions were the main contributor to acidification (0.35 kg SO2-eq) in IVC, while AD exerted less impact on acidification (0.09 kg SO2-eq) and nutrient enrichment (0.25 kg NO3-eq) attributed to the counteract of energy recovery. 2029 would be the inflection point for global warming potential in AD with more clean energy applied in electricity mix in China. For nutrient recovery, more C (8.3%), N (37.9%) and P (66.7%) could be recovered in compost, while those were discharged via leachate and biogas residue in AD. The cost of IVC was 16 CNY/t (2.40 USD/t) lower than AD. Combing the three key indexes and the sale routes of products, IVC was recommended to be used in areas dominated by agriculture and forestry industries, and AD was more suitable for large cities.


Asunto(s)
Compostaje , Eliminación de Residuos , Administración de Residuos , Anaerobiosis , Dióxido de Carbono/análisis , Ambiente , Alimentos , Nutrientes , Residuos Sólidos/análisis
10.
Bioresour Technol ; 351: 126966, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35278624

RESUMEN

The influence of cerium dioxide nanoparticles (CeO2 NPs) on biological nitrogen removal and associated nitrous oxide (N2O) emission has seldom been addressed yet. Herein, the chronic effect of CeO2 NPs on the nitrogen transformation processes during wastewater treatment and the impacted system's self-recovery potential after CeO2 NP stress removal were investigated. CeO2 NP of 10-50 mg/L induced significant declines of the ammonia nitrogen (NH4+-N) and the total nitrogen removal efficiencies, but triggered the nitrite accumulation and the N2O emission. The N2O reductase (NOS) activity was negatively correlated with the N2O emission level, and the inhibition of NOS activity under CeO2 NP stress was probably due to the depressions of the sludge denitrifiers' metabolic activities. The NH4+-N removal efficiency was successfully regained after the recovery period although the N2O emission level was still higher than the pre-exposure period, which was probably due to the residual CeO2 NPs inside the activated sludge.


Asunto(s)
Nanopartículas , Óxido Nitroso , Reactores Biológicos , Cerio , Desnitrificación , Nitrificación , Nitrógeno/metabolismo , Óxido Nitroso/análisis , Aguas del Alcantarillado
11.
Water Res ; 213: 118153, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35152135

RESUMEN

Electrochemical anaerobic membrane bioreactor attracted attention due to stable treatment quality with low footprint, and draw solute has significant effect on the sludge characteristics and membrane fouling performance. In this pilot-scale study, an electrochemical anaerobic membrane bioreactor (E-AnMBR) was proposed for treating pesticide wastewater at different hydraulic retention times (HRTs), demonstrating that E-AnMBR was superior on improvement of sludge characteristics and mitigation of membrane fouling, compared with the conventional anaerobic membrane bioreactor (C-AnMBR). E-AnMBR reduced sludge yield by 41.2 ± 6.7% and the SVI was significantly decreased by 32.5±13.8%. The accumulation of VFA in E-AnMBR was slighter than that of C-AnMBR, and the minimum average VFA was 255±6 mg/L. The methane yield of E-AnMBR (0.22-0.29 L CH4/g CODremoved) was 1.2-1.4 times than that of C-AnMBR. The EPS contents in suspended and attached sludge of E-AnMBR were significantly reduced by 41.8 ± 3.3% and 77.4 ± 14.5% than that of C-AnMBR, respectively. These results suggested that E-AnMBR has lower sludge disposal pressure, higher stability and methane recovery potential. Not only that, E-AnMBR successfully reduced membrane resistance, delaying the fouling rate by 31.0-38.5%. Finally, the linear relationship between EPS characteristics and membrane pollution was determined.

12.
Environ Sci Policy ; 117: 34-45, 2021 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34744509

RESUMEN

The frequency and severity of shocks to food systems is accelerating globally, exemplified by the current COVID-19 outbreak. In low- and middle-income countries, the impacts have exacerbated existing food system vulnerabilities and poverty. Governments and donors must respond quickly, but few tools are available that identify interventions to build food system resilience, or emerging opportunities for transformation. In this paper we reflect on the application of a systems-based rapid assessment which we applied across 11 Indo-Pacific countries in May-July 2020. Our approach was shaped by three design parameters: the integration of key informants' perspectives engaged remotely within the countries, applicability to diverse food systems and COVID-19 experiences across the region, and the consideration of food systems as complex systems. For the rapid assessment we adopted an analytical framework proposed by Allen and Prosperi (2016). To include a development lens, we added the analysis of vulnerable groups and their exposure, impacts, recovery potential and resilience, and pro-poor interventions. We concluded that the framework and approach facilitated integration and triangulation of disparate knowledge types and data to identify priority interventions and was sufficiently flexible to be applied across food systems, at both national, sub-national and commodity scales. The step-wise method was simple and enabled structured inquiry and reporting. Although the systems concepts appeared more easily transferrable to key informants in some countries than others, potentially transformational interventions were identified, and also some risks of maladaptation. We present a refined framework that emphasises analysis of political, economic and institutional drivers of exposure and vulnerability, the constraints that they pose for building recovery potential and resilience, and trade-offs amongst winners and losers inherent in proposed interventions.

13.
Evol Appl ; 14(10): 2378-2391, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34745332

RESUMEN

Fisheries exploitation can cause genetic changes in heritable traits of targeted stocks. The direction of selective pressure forced by harvest acts typically in reverse to natural selection and selects for explicit life histories, usually for younger and smaller spawners with deprived spawning potential. While the consequences that such selection might have on the population dynamics of a single species are well emphasized, we are just beginning to perceive the variety and severity of its propagating effects within the entire marine food webs and ecosystems. Here, we highlight the potential pathways in which fisheries-induced evolution, driven by size-selective fishing, might resonate through globally connected systems. We look at: (i) how a size truncation may induce shifts in ecological niches of harvested species, (ii) how a changed maturation schedule might affect the spawning potential and biomass flow, (iii) how changes in life histories can initiate trophic cascades, (iv) how the role of apex predators may be shifting and (v) whether fisheries-induced evolution could codrive species to depletion and biodiversity loss. Globally increasing effective fishing effort and the uncertain reversibility of eco-evolutionary change induced by fisheries necessitate further research, discussion and precautionary action considering the impacts of fisheries-induced evolution within marine food webs.

14.
Front Neurosci ; 15: 678965, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34393705

RESUMEN

For humans, the ability to effectively adapt footfall rhythm to perturbations is critical for stable locomotion. However, only limited information exists regarding how dynamic stability changes when individuals modify their footfall rhythm. In this study, we recorded 3D kinematic activity from 20 participants (13 males, 18-30 years old) during walking on a treadmill while synchronizing with an auditory metronome sequence individualized to their baseline walking characteristics. The sequence then included unexpected temporal perturbations in the beat intervals with the subjects required to adapt their footfall rhythm accordingly. Building on a novel approach to quantify resilience of locomotor behavior, this study found that, in response to auditory perturbation, the mean center of mass (COM) recovery time across all participants who showed deviation from steady state (N = 15) was 7.4 (8.9) s. Importantly, recovery of footfall synchronization with the metronome beats after perturbation was achieved prior (+3.4 [95.0% CI +0.1, +9.5] s) to the recovery of COM kinematics. These results highlight the scale of temporal adaptation to perturbations and provide implications for understanding regulation of rhythm and balance. Thus, our study extends the sensorimotor synchronization paradigm to include analysis of COM recovery time toward improving our understanding of an individual's resilience to perturbations and potentially also their fall risk.

15.
Bioresour Technol ; 340: 125728, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34385130

RESUMEN

This study proposes a novel strategy to obtain high-efficiency synchronous removal of nitrogen and phosphorus from wastewater by the limited-aeration anaerobic/anoxic/aerobic membrane bioreactor (AAO-MBR) and evaluates its resource recovery potential. Effects of membrane flux on pollutants removal and membrane fouling were investigated, and the optimal flux of 30 L/(m2·h) was obtained with efficient nitrogen and phosphorus removal of 81.5 ± 6.1% and 96.7 ± 2.1%. Compared with traditional and chemical-aided AAO-MBRs, limited-aeration AAO-MBR also alleviated membrane fouling by enlarging sludge flocs, improved sludge activities, and enriched the functional bacteria and genes. The sludge denitrification activity and phosphorus uptake activity of the limited-aeration AAO-MBR were 1.7 and 4.2 times as those of the traditional AAO-MBR. Low-temperature sludge pyrolysis results showed that sludge from limited-aeration AAO-MBR had higher nutrient storage and release capacity. This study proved the efficient nutrient removal capacity and high resource recovery potential of the limited-aeration AAO-MBR process.


Asunto(s)
Reactores Biológicos , Eliminación de Residuos Líquidos , Anaerobiosis , Nutrientes , Aguas del Alcantarillado
16.
Waste Manag ; 126: 141-151, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33756114

RESUMEN

The coupling of sanitation system and agriculture production is essential to mitigate the environmental burden and offset unsustainable fertilizer utilization by employing resource-oriented sanitation. Yet, the economic feasibility and energy recovery potential from domestic waste have rarely been investigated. To assess four scenarios (whether with kitchen waste separation; whether with energy recovery) in the resource-oriented sanitation system, an integrated assessment framework based on energy analysis and techno-economic analysis is employed to investigate the comprehensive sanitation system including both wastewater treatment and solid waste disposal. The results show that energy recovery from human excreta and kitchen waste can offset the energy consumption of the sanitation system and the energy surplus can even be 1067.70 kJ·PE-1·day-1. The optimum covering range of the regional recovery center was quantified from the balance between scale effect and spatial distribution, and the serving inhabitants need to be more than 2800.


Asunto(s)
Eliminación de Residuos , Purificación del Agua , Agricultura , Fertilizantes , Humanos , Saneamiento , Eliminación de Residuos Líquidos , Aguas Residuales
17.
J Exp Biol ; 224(Pt 5)2021 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-33536309

RESUMEN

The capacity to recover after a perturbation is a well-known intrinsic property of physiological systems, including the locomotor system, and can be termed 'resilience'. Despite an abundance of metrics proposed to measure the complex dynamics of bipedal locomotion, analytical tools for quantifying resilience are lacking. Here, we introduce a novel method to directly quantify resilience to perturbations during locomotion. We examined the extent to which synchronizing stepping with two different temporal structured auditory stimuli (periodic and 1/f structure) during walking modulates resilience to a large unexpected perturbation. Recovery time after perturbation was calculated from the horizontal velocity of the body's center of mass. Our results indicate that synchronizing stepping with a 1/f stimulus elicited greater resilience to mechanical perturbations during walking compared with the periodic stimulus (3.3 s faster). Our proposed method may help to gain a comprehensive understanding of movement recovery behavior of humans and other animals in their ecological contexts.


Asunto(s)
Marcha , Locomoción , Animales , Humanos , Movimiento , Caminata
18.
Bioresour Technol ; 327: 124797, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33592491

RESUMEN

The nitrogen transformation performances and greenhouse gas nitrous oxide (N2O) emissions in a sequencing batch reactor under chronic exposure to zinc oxide nanoparticles (ZnO NPs) were quantified and the system's self-recovery potentials were assessed. ZnO NPs posed a dose-dependent depression effect on the removal efficiencies of ammonia nitrogen (NH4+-N) and total nitrogen (TN), and the N2O emissions. The suppressed N2O emissions had a positive relationship with the activity ratios of nitrite/NO reductases and N2O reductase, and were expected to be caused by the inhibited heterotrophic denitrification process. The inhibition of glucose metabolism key enzymes and electron transport chain activities would be responsible for the heterotrophic denitrification performances deterioration. Furthermore, the removal efficiencies of NH4+-N and TN were recovered to control levels through the nitrite-shunt. However, the N2O emission increased significantly above the control during the recovery period mainly due to the irreversibility of the depressed nitrite oxidation activities.


Asunto(s)
Nanopartículas , Óxido de Zinc , Reactores Biológicos , Desnitrificación , Nitrógeno , Óxido Nitroso
19.
Conserv Biol ; 35(2): 643-653, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-32671869

RESUMEN

Megafauna species are intrinsically vulnerable to human impact. Freshwater megafauna (i.e., freshwater animals ≥30 kg, including fishes, mammals, reptiles, and amphibians) are subject to intensive and increasing threats. Thirty-four species are listed as critically endangered on the International Union for Conservation of Nature (IUCN). Red List of Threatened Species, the assessments for which are an important basis for conservation actions but remain incomplete for 49 (24%) freshwater megafauna species. Consequently, the window of opportunity for protecting these species could be missed. Identifying the factors that predispose freshwater megafauna to extinction can help predict their extinction risk and facilitate more effective and proactive conservation actions. Thus, we collated 8 life-history traits for 206 freshwater megafauna species. We used generalized linear mixed models to examine the relationships between extinction risk based on the IUCN Red List categories and the combined effect of multiple traits, as well as the effect of human impact on these relationships for 157 classified species. The most parsimonious model included human impact and traits related to species' recovery potential including life span, age at maturity, and fecundity. Applying the most parsimonious model to 49 unclassified species predicted that 17 of them are threatened. Accounting for model predictions together with IUCN Red List assessments, 50% of all freshwater megafauna species are considered threatened. The Amazon and Yangtze basins emerged as global diversity hotspots of threatened freshwater megafauna, in addition to existing hotspots, including the Ganges-Brahmaputra and Mekong basins and the Caspian Sea region. Assessment and monitoring of those species predicted to be threatened are needed, especially in the Amazon and Yangtze basins. Investigation of life-history traits and trends in population and distribution, regulation of overexploitation, maintaining river connectivity, implementing protected areas focusing on freshwater ecosystems, and integrated basin management are required to protect threatened freshwater megafauna in diversity hotspots.


Efectos Combinados de los Rasgos de la Historia de Vida y el Impacto Humano sobre el Riesgo de Extinción de la Megafauna de Agua Dulce Resumen Las especies de megafauna son intrínsecamente vulnerables al impacto humano. La megafauna de agua dulce (es decir, los animales ≥30 kg, incluyendo peces, mamíferos, reptiles y anfibios) está sujeta a amenazas intensivas y en aumento. La Lista Roja de la UICN (Unión Internacional para la Conservación de la Naturaleza) lista a 34 especies en peligro crítico de extinción. Las evaluaciones para esta lista son un cimiento importante para las acciones de conservación, pero permanecen incompletas para 49 (24%) de las especies de megafauna de agua dulce. Como consecuencia, la ventana de oportunidad para la protección de estas especies podría perderse. La identificación de los factores que predisponen a la megafauna de agua dulce a la extinción puede ayudar a predecir el riesgo de extinción para cada especie y facilitar acciones de conservación más efectivas y proactivas. Por lo anterior, recopilamos ocho rasgos de historia de vida para 206 especies de megafauna de agua dulce. Usamos modelos lineales generalizados mixtos para examinar las relaciones entre el riesgo de extinción medido con base en las categorías de la Lista Roja de la UICN y el efecto combinado de diferentes rasgos, así como el efecto del impacto humano sobre estas relaciones para 157 especies clasificadas. El modelo más parsimonioso incluyó al impacto humano y a los rasgos relacionados con el potencial de recuperación de las especies como el ciclo de vida, edad de madurez y fecundidad. La aplicación de este modelo a las 49 especies sin clasificación pronosticó que 17 de ellas están amenazadas. Si consideramos las predicciones del modelo junto con las evaluaciones de la Lista Roja de la UICN, el 50% de todas las especies de megafauna de agua dulce están consideradas como amenazadas. Las cuencas del Amazonas y del Yangtze surgieron como puntos calientes de diversidad mundial, junto con las cuencas del Ganges-Brahmaputra y el Mekong y la región del mar Caspio. Es urgente evaluar y monitorear a aquellas especies que se pronostica estén amenazadas, especialmente en las cuencas del Amazonas y del Yangtze. Se requieren investigaciones sobre los rasgos de la historia de vida y las tendencias poblacionales y de distribución, la regulación de la sobreexplotación, el mantenimiento de la conectividad entre ríos, la implementación de áreas protegidas enfocadas en los ecosistemas de agua dulce y un manejo integrado de cuencas para proteger a la megafauna de agua dulce en los puntos calientes de diversidad.


Asunto(s)
Ecosistema , Extinción Biológica , Animales , Biodiversidad , Conservación de los Recursos Naturales , Especies en Peligro de Extinción , Agua Dulce , Humanos
20.
Waste Manag ; 116: 31-39, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32784119

RESUMEN

This paper presents an inventory of sewage sludge ashes (SSA) generated in the mono-incineration plants for municipal sewage sludge in Poland. This research focused on the detailed study of mass flows, chemical composition, and phosphorus recovery potential. There are currently 11 sludge mono-incineration plants operated with a total capacity of 160,300 Mg dry weight (d.w.) of sludge annually. Recently, a significant increase in the amount of SSA generated in these plants has been observed, reaching 26,756 Mg in 2018. Chemical composition of SSA showed significant amounts of the main nutrients: calcium (~14%), phosphorus (~13%), magnesium (~3%), and potassium (~1%). Additional main elements were iron (~14.5%), silicon (~13%), and aluminium (~6%). The main trace elements in the SSA were zinc (~3750 mg/kg) and copper (~899 mg/kg). Pollutants, according to fertilizer regulations of different countries, present in Polish SSA were chromium (~703 mg/kg), nickel (~260 mg/kg), lead (~94 mg/kg), and cadmium (~9 mg/kg). The radionuclides, uranium, and thorium often present in higher amounts in commercial phosphate rock-based fertilizers, were only detected in SSA at low levels of 4-9 mg/kg and 2-3 mg/kg, respectively. Theoretical phosphorus recovery potential from the SSA (from plants in Cracow, Lodz, Gdansk, Gdynia, Szczecin, and Kielce) was estimated at 1613.8 Mg, of which 33.9% is bioavailable. Currently, in Poland, the recommended approach is the production of fertilizers as a result of the extraction of phosphorus from the SSA with its use in the production of secondary mineral fertilizers. Further research in this area is required considering Polish conditions and legislation.


Asunto(s)
Fósforo/análisis , Aguas del Alcantarillado , Fertilizantes , Incineración , Polonia
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