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1.
Environ Sci Technol ; 58(15): 6659-6669, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38557040

RESUMEN

Revealing the role of functional redundancy is of great importance considering its key role in maintaining the stability of microbial ecosystems in response to various disturbances. However, experimental evidence on this point is still lacking due to the difficulty in "manipulating" and depicting the degree of redundancy. In this study, manipulative experiments of functional redundancy were conducted by adopting the mixed inoculation strategy to evaluate its role in engineered anaerobic digestion systems under ammonium inhibition conditions. The results indicated that the functional redundancy gradient was successfully constructed and confirmed by evidence from pathway levels. All mixed inoculation groups exhibited higher methane production regardless of the ammonium level, indicating that functional redundancy is crucial in maintaining the system's efficiency. Further analysis of the metagenome-assembled genomes within different functional guilds revealed that the extent of redundancy decreased along the direction of the anaerobic digestion flow, and the role of functional redundancy appeared to be related to the stress level. The study also found that microbial diversity of key functional populations might play a more important role than their abundance on the system's performance under stress. The findings provide direct evidence and highlight the critical role of functional redundancy in enhancing the efficiency and stability of anaerobic digestion.


Asunto(s)
Compuestos de Amonio , Microbiota , Anaerobiosis , Reactores Biológicos , Metagenoma , Metano
2.
Environ Sci Technol ; 58(26): 11685-11694, 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38905014

RESUMEN

A regular tetrahedron model was established to pierce the fractionation of dissolved organic matter (DOM) among quaternary components by using high-resolution mass spectrometry. The model can stereoscopically visualize molecular formulas of DOM to show the preference to each component according to the position in a regular tetrahedron. A classification method was subsequently developed to divide molecular formulas into 15 categories related to fractionation ratios, the relative change of which was demonstrated to be convergent with the uncertainty of mass peak area. The practicality of the regular tetrahedron model was verified by seven kinds of sludge from waste leachate treatment and sewage wastewater treatment plants by using stratification of extracellular polymeric substances coupled with Orbitrap MS as an example, presenting the DOM chemodiversity in stratified sludge flocs. Sensitivity analysis proved that classification results were relatively stable with the perturbation of four model parameters. Multinomial logistic regression analysis could further help identify the effect of molecular properties on the fractionation of DOM based on the classification results of the regular tetrahedron model. This model offers a methodology for the assessment of specificity of sequential extraction on DOM from solid or semisolid components and simplifies the complex mathematical expression of fractionation coefficients for quaternary components.


Asunto(s)
Espectrometría de Masas , Aguas del Alcantarillado , Aguas del Alcantarillado/química , Compuestos Orgánicos/química , Fraccionamiento Químico , Modelos Teóricos , Aguas Residuales/química
3.
Anal Chem ; 95(9): 4412-4420, 2023 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-36820858

RESUMEN

Insights into carbon sources (biogenic and fossil carbon) and contents in solid waste are vital for estimating the carbon emissions from incineration plants. However, the traditional methods are time-, labor-, and cost-intensive. Herein, high-quality data sets were established after analyzing the carbon contents and infrared spectra of substantial samples using elemental analysis and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), respectively. Then, five classification and eight regression machine learning (ML) models were evaluated to recognize the proportion of biogenic and fossil carbon in solid waste. Using the optimized data preprocessing approach, the random forest (RF) classifier with hyperparameter tuning ranked first in classifying the carbon group with a test accuracy of 0.969, and the carbon contents were successfully predicted by the RF regressor with R2 = 0.926 considering performance-interpretability-computation time competition. The above proposed algorithms were further validated with real environmental samples, which exhibited robust performance with an accuracy of 0.898 for carbon group classification and an R2 value of 0.851 for carbon content prediction. The reliable results indicate that ATR-FTIR coupled with ML algorithms is feasible for rapidly identifying both carbon groups and content, facilitating the calculation and assessment of carbon emissions from solid waste incineration.

4.
Environ Sci Technol ; 57(42): 16033-16042, 2023 10 24.
Artículo en Inglés | MEDLINE | ID: mdl-37822265

RESUMEN

Halogenated organic compounds in wastewater are persistent and bioaccumulative contaminants of great concern, but few are known at the molecular level. Herein, we focus on nontarget screening of halogenated dissolved organic matter (DOM) in highly concentrated organic matrices of waste leachates and their concentrates. Solid-phase extraction (SPE) was optimized before capturing halogenated signatures via HaloSeeker 2.0 software on mining full-scan high-resolution mass spectrometry (HRMS) fingerprints. This study identified 438 Cl-/Br-containing DOM formulas in 21 leachates and membrane concentrates. Among them, 334 formulas were achieved via SPE with mixed-sorbent cartridges (mixed-SPE), surpassing the 164 formulas achieved through Bond Elut PPL cartridges (PPL-SPE). Herein, only four samples identified via PPL-SPE exhibited a resolution of >50% for extracted Cl-/Br-containing DOM by either SPE. The halogenated DOM constituted 6.87% of the total DOM mass features. Nevertheless, more abundant adsorbable organic halogens deciphered waste leachates and highly concentrated waste streams as reservoirs for halogenated contaminants. Remarkably, 75.7-98.1% of Cl-/Br-containing DOM in primary membrane concentrates remained stable through the secondary membrane treatment, indicating the persistence of these unknown contaminants even post-treatment.


Asunto(s)
Materia Orgánica Disuelta , Compuestos Orgánicos , Espectrometría de Masas , Compuestos Orgánicos/análisis , Aguas Residuales , Extracción en Fase Sólida/métodos
5.
J Environ Sci (China) ; 63: 58-67, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29406117

RESUMEN

The use of coal fly ash (CFA), municipal solid waste incinerator bottom ash (MSWIBA) and flue gas desulfurization residue (FGDR) in road construction has become very common owing to its economical advantages. However, these residues may contain toxic constituents that pose an environmental risk if they leach out and flow through the soil, surface water and groundwater. Therefore, it is necessary to assess the ecotoxicity and groundwater impact of these residues before decisions can be made regarding their utilization for road construction. In this study, the physico-chemical characteristics, leaching and phytotoxicity of these residues were investigated. Specifically, multivariate analyses were used to evaluate the contributions of the leaching constituents of the CFA, MSWIBA and FGDR leachates to the germination index of wheat seeds. B, Ba, Cr, Cu, Fe and Pb were found to be more toxic to the wheat seeds than the other heavy metals. Furthermore, the leached concentrations of the constituents from the CFA, MSWIBA and FGDR were below the regulatory threshold limits of the Chinese identification standard for hazardous wastes. Analyses conducted using a numerical groundwater model (WiscLEACH) indicated that the predicted field concentrations of metals from the CFA, MSWIBA and FGDR increased with time up to about 30years at the point of compliance, then decreased with time and distance. Overall, this study demonstrated that the risks resulting from MSWIBA, CFA and FGDR leaching could be assessed before its utilization for road construction, providing crucial information for the adoption of these alternative materials.


Asunto(s)
Materiales de Construcción , Monitoreo del Ambiente , Agua Subterránea/química , Transportes , Contaminantes Químicos del Agua/análisis , Ceniza del Carbón/química , Incineración , Metales Pesados/análisis
6.
J Environ Sci (China) ; 74: 1-10, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30340662

RESUMEN

Chemical waste compositions are important for municipal solid waste management, as they determine the pollution potentials from different waste strategies. A representative dataset for chemical characteristics of individual waste fractions is frequently required to assess chemical waste composition, but it is usually reported in developed countries and not in developing countries. In this study, a dataset for Chinese waste was established through careful data screening and assessment, named as CN dataset. Meanwhile, a dataset for Danish waste (DK dataset) was also summarized based on previous studies. In order to quantitatively evaluate the reliabilities of CN and DK datasets, the chemical waste compositions in four Chinese cities were estimated by utilizing both of them, respectively. It is indicated that the usage of CN datasets led to significantly lower discrepancies from the actual values based on laboratory analysis in most cases. Within the datasets, the moisture contents of food waste, paper, textiles, and plastics, the carbon content of food waste, as well as the oxygen content of plastics would induce significant divergences, which should be paid special attention when gathering the information. In addition, the fractional waste compositions in China showed similar features with other developing countries but differ significantly with developed countries. Thus the above-mentioned conclusions could also be true in other developing countries.


Asunto(s)
Residuos Sólidos/análisis , China , Ciudades , Bases de Datos Factuales , Dinamarca , Administración de Residuos
7.
Waste Manag Res ; 35(5): 508-514, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28093954

RESUMEN

This research focused on the inhibitory effects of Ca on the aerobic biological treatment of landfill leachate containing extremely high Ca concentrations. When the Ca concentration in leachate to be treated was more than 4500 mg l-1, the total organic carbon removal rate was significantly reduced and the processing time to achieve the same removal efficiency was 1.4 times that in the control treatment without added Ca. In contrast, the total nitrogen and ammonia nitrogen (NH4+-N) removal efficiencies were positively related to the Ca concentration, increasing from 65.2% to 81.2% and from 69.2% to 83.7%, respectively, when the dosage of added Ca increased from zero to 8000 mg l-1. During aerobic treatment, the reductions of solution Ca concentration were in the range of 1003-2274 mg l-1 and were matched with increases in the Ca content in the residual sludge. The inhibition threshold of Ca in the leachate treated by the activated sludge process appeared to be 4500 mg l-1, which could be realized by controlling the influent Ca concentration and using an appropriate sludge return ratio in the activated sludge process.


Asunto(s)
Calcio , Residuos Sólidos , Reactores Biológicos , Nitrógeno , Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Contaminantes Químicos del Agua
8.
J Environ Manage ; 129: 510-21, 2013 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-24018116

RESUMEN

Reducing greenhouse gas (GHG) emissions from municipal solid waste (MSW) treatment can be highly cost-effective in terms of GHG mitigation. This study investigated GHG emissions during MSW landfilling in China under four existing scenarios and in terms of seven different categories: waste collection and transportation, landfill management, leachate treatment, fugitive CH4 (FM) emissions, substitution of electricity production, carbon sequestration and N2O and CO emissions. GHG emissions from simple sanitary landfilling technology where no landfill gas (LFG) extraction took place (Scenario 1) were higher (641-998 kg CO2-eq·t(-1)ww) than those from open dump (Scenario 0, 480-734 kg CO2-eq·t(-1)ww). This was due to the strictly anaerobic conditions in Scenario 1. LFG collection and treatment reduced GHG emissions to 448-684 kg CO2-eq·t(-1)ww in Scenario 2 (with LFG flare) and 214-277 kg CO2-eq·t(-1)ww in Scenario 3 (using LFG for electricity production). Amongst the seven categories, FM was the predominant contributor to GHG emissions. Global sensitivity analysis demonstrated that the parameters associated with waste characteristics (i.e. CH4 potential and carbon sequestered faction) and LFG management (i.e. LFG collection efficiency and CH4 oxidation efficiency) were of great importance. A further learning on the MSW in China indicated that water content and dry matter content of food waste were the basic factors affecting GHG emissions. Source separation of food waste, as well as increasing the incineration ratio of mixed collected MSW, could effectively mitigate the overall GHG emissions from landfilling in a specific city. To increase the LFG collection and CH4 oxidation efficiencies could considerably reduce GHG emissions on the landfill site level. While, the improvement in the LFG utilization measures had an insignificant impact as long as the LFG is recovered for energy generation.


Asunto(s)
Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Contaminación del Aire/prevención & control , Restauración y Remediación Ambiental/métodos , Gases/análisis , Instalaciones de Eliminación de Residuos , China , Efecto Invernadero , Modelos Teóricos , Eliminación de Residuos , Programas Informáticos
9.
J Air Waste Manag Assoc ; 62(4): 461-70, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22616288

RESUMEN

Because volatile organic compounds (VOCs) are one of the main concerns during municipal solid waste (MSW) treatment, the release patterns and the environmental effects of VOCs were investigated during laboratory-scale aerobic biotreatments of MSW with continuous and intermittent negative ventilation. When the same airflow amounts were used, intermittent ventilation was found to reduce the total VOC emissions from continuous ventilation process by 28%. In this study, 23 types of volatile organic compounds were analyzed, of which butyraldehyde, ethanol, and butanone were emitted in the highest concentrations of 748, 372, and 260 mg/m3, respectively. During the aerobic biotreatment process, ketones, aldehydes, and alcohols were primarily released during the first 4 days, accounting for 86-98% of the total VOC emissions during this period. The emission concentrations of malodorous sulfide compounds displayed two peaks on day 4 and day 9, with the contribution to the total VOC emissions being enhanced from less than 10% to 76-83%. The release of terpenes and aromatics lasted for more than 10 days with no significant emission peaks and the proportions of those compounds in the total VOCs increased gradually, but no more than 50% even at the end of the process. Considering the strength of the odors, aldehydes were the predominant contributors at the beginning of the experiment, whereas malodorous sulfide compounds became the most odorous compound as the biological process continued. Most of the VOCs emitted at the concentrations beneath the level causing health threat to the workers.


Asunto(s)
Contaminantes Atmosféricos/química , Eliminación de Residuos/métodos , Compuestos Orgánicos Volátiles/química , Compuestos Orgánicos Volátiles/metabolismo , Aerobiosis , Reactores Biológicos , Odorantes , Oxígeno , Temperatura , Factores de Tiempo
10.
Waste Manag Res ; 30(12): 1272-80, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23035038

RESUMEN

Ventilation is very important during the biodrying process because it affects the biodrying efficiency and secondary pollution. In this study, three ventilation modes-intermittent negative ventilation (IN), continuous negative ventilation (CN) and intermittent positive ventilation (IP)-were used to provide the same amount of total air during biodrying of municipal solid waste (MSW). During the entire 16-day experiment, 68.4%, 68.7% and 67.2% of water contained in the initial waste was removed under IN, CN and IP trials respectively. The ratio of water loss to volatile solid loss was used to evaluate the biodrying efficiency, with values of 5.35, 5.93 and 4.82 being observed for IN, CN and IP trials respectively. The total organic carbon concentrations of the leachate generated from the biodrying of waste were as high as 25,000 mg/l, while those of the condensate were not higher than 3500 mg/l. During the entire process, the average ammonia concentrations of leachate and condensate were 1350 mg/l and 2140 mg/l respectively. From the aspect of biodrying efficiency, continuous negative ventilation was the most preferable ventilation mode for biodrying of MSW, while special care should be taken to prevent aqueous pollution if it is used in a MSW treatment plant.


Asunto(s)
Desecación , Eliminación de Residuos/métodos , Residuos Sólidos/análisis , Ventilación/métodos , Amoníaco/análisis , Carbono/análisis , China , Oxígeno/análisis , Ventilación/instrumentación
11.
J Hazard Mater ; 423(Pt B): 127144, 2022 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-34555763

RESUMEN

During coronavirus disease 2019 pandemic, the exponential increase in clinical waste (CW) generation has caused immense burden to CW treatment facilities. Co-incineration of CW in municipal solid waste incinerator (MSWI) is an emergency treatment method. A material flow model was developed to estimate the change in feedstock characteristics and resulting acid gas emission under different CW co-incineration ratios. The ash contents and lower heating values of the feedstocks, as well as HCl concentrations in flue gas showed an upward trend. Subsequently, 72 incineration residue samples were collected from a MSWI performing co-incineration (CW ratio <10 wt%) in Wuhan city, China, followed by 20 incineration residues samples from waste that were not co-incineration. The results showed that the contents of major elements and non-volatile heavy metals in the air pollution control residues increased during co-incineration but were within the reported ranges, whereas those in the bottom ashes revealed no significant changes. The impact of CW co-incineration at a ratio <10 wt% on the distribution of elements in the incineration residues was not significant. However, increase in alkali metals and HCl in flue gas may cause potential boiler corrosion. These results provide valuable insights into pollution control in MSWI during pandemic.


Asunto(s)
COVID-19 , Metales Pesados , Eliminación de Residuos , Ceniza del Carbón , Humanos , Incineración , Pandemias , SARS-CoV-2 , Residuos Sólidos/análisis
12.
Waste Manag ; 153: 20-30, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36041267

RESUMEN

Rapid determination of moisture content plays an important role in guiding the recycling, treatment and disposal of solid waste, as the moisture content of solid waste directly affects the leachate generation, microbial activities, pollutants leaching and energy consumption during thermal treatment. Traditional moisture content measurement methods are time-consuming, cumbersome and destructive to samples. Therefore, a rapid and nondestructive method for determining the moisture content of solid waste has become a key technology. In this work, an attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and multiple machine learning methods was developed to predict the moisture content of multi-source solid waste (textile, paper, leather and wood waste). A combined model was proposed for moisture content regression prediction, and the applicability of 20 combinations of five spectral preprocessing methods and four regression algorithms were discussed to further improve the modeling accuracy. Furthermore, the prediction result based on the water-band spectra was compared with the prediction result based on the full-band spectra. The result showed that the combination model can efficiently predict the moisture content of multi-source solid waste, and the R2 values of the validation and test datasets and the root mean square error for the moisture prediction reached 0.9604, 0.9660, and 3.80, respectively after the hyperparameter optimization. The excellent performance indicated that the proposed combined models can rapidly and accurately measure the moisture content of solid waste, which is significant for the existing waste characterization scheme, and for the further real-time monitoring and management of solid waste treatment and disposal process.


Asunto(s)
Contaminantes Ambientales , Residuos Sólidos , Aprendizaje Automático , Residuos Sólidos/análisis , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Agua/química
13.
Huan Jing Ke Xue ; 43(9): 4506-4512, 2022 Sep 08.
Artículo en Zh | MEDLINE | ID: mdl-36096591

RESUMEN

In order to explore the source characteristics as well as the temporal and spatial variations in odor pollution in municipal waste landfills, gas samples were collected from a landfill in an eastern coastal area of China throughout winter and summer. The total concentration of malodorous substances reached 60000 µg·m-3. There were more types of odor pollutants detected in summer than in winter, the average concentration was 30-300 times higher than that in winter, and the concentration of sulfur compounds increased by 4.7-136.7 times in summer. Oxygenated compounds had the highest concentration, and the total concentration of sulfur compounds accounted for less than 10% of malodorous substances. However, sulfur compounds contributed more than 90% to the theoretical odor concentration. Sulfur compounds such as methyl mercaptan and propane mercaptan were the key odorants in the landfill. After the landfill unit was covered, the concentration of odorous substances and the theoretical odor concentration on the surface of the landfill showed an increasing trend with time, indicating that the covering had a certain odor barrier effect; however, the landfill unit still had a large odor release potential. The similarity analysis showed that the odorous gas accumulated in the unit with temporary cover and without an exhaust system could be released to the environment through the overlapping gap of the membrane and the location of membrane rupture, resulting in more serious odor pollution around the landfill at night than that during the day.


Asunto(s)
Contaminantes Atmosféricos , Eliminación de Residuos , Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente/métodos , Odorantes/análisis , Eliminación de Residuos/métodos , Residuos Sólidos/análisis , Compuestos de Sulfhidrilo/análisis , Compuestos de Azufre/análisis , Instalaciones de Eliminación de Residuos
14.
J Hazard Mater ; 427: 128210, 2022 Apr 05.
Artículo en Inglés | MEDLINE | ID: mdl-34999401

RESUMEN

Polyvinyl chloride (PVC) is one of the most commonly used plastics. The treatment and recycling of PVC waste is still challenging, due to its non-biodegradability, low thermal stability, high Cl content and low product value. In this study, a one-pot method was developed to upcycle PVC into valuable carbon materials, pipeline-quality pyrolysis gas and chlorides. The well-designed process included dechlorination by Cl-fixative (ZnO or KOH), carbonization of dechlorinated polyenes, and modification of carbon materials in sequence. ZnO and KOH converted 84.48% and 94.15% of total Cl into corresponding chlorides, respectively. CH4 and H2 accounted for 81.87-99.34 vol% of pyrolysis gas with higher heat values of 30.11-32.84 MJ m-3, which can be used as substitute natural gas. As high as 83.13% of the C element was converted into carbon materials. The morphology, structure and property of carbon materials can be modified by different Cl-fixatives. Millimeter-scale carbon spheres with mono-dispersity and porous carbon with a high specific surface area of 1922 m2 g-1 were obtained when ZnO and KOH were added, respectively. Moreover, the reaction mechanisms of PVC with Cl-fixatives were also deciphered through thermogravimetric analysis and thermodynamic simulation.

15.
Environ Sci Technol ; 45(2): 508-13, 2011 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-21162559

RESUMEN

To quantify the contribution of syntrophic acetate oxidation to thermophilic anaerobic methanogenesis under the stressed condition induced by acidification, the methanogenic conversion process of 100 mmol/L acetate was monitored simultaneously by using isotopic tracing and selective inhibition techniques, supplemented with the analysis of unculturable microorganisms. Both quantitative methods demonstrated that, in the presence of aceticlastic and hydrogenotrophic methanogens, a large percentage of methane (up to 89%) was initially derived from CO(2) reduction, indicating the predominant contribution of the syntrophic acetate oxidation pathway to acetate degradation at high acid concentrations. A temporal decrease of the fraction of hydrogenotrophic methanogenesis from more than 60% to less than 40% reflected the gradual prevalence of the aceticlastic methanogenesis pathway along with the reduction of acetate. This apparent discrimination of acetate methanization pathways highlighted the importance of the syntrophic acetate-oxidizing bacteria to initialize methanogenesis from high organic loadings.


Asunto(s)
Acetatos/metabolismo , Bacterias/metabolismo , Metano/metabolismo , Anaerobiosis , Bacterias/clasificación , Bacterias/genética , Dióxido de Carbono/metabolismo , Cadena Alimentaria , Interacciones Microbianas , Oxidación-Reducción , Temperatura
16.
J Environ Manage ; 92(10): 2533-8, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21640472

RESUMEN

Biostabilization can remove considerable amounts of moisture and degradable organic materials from municipal solid waste (MSW), and can therefore be an effective form of pretreatment prior to landfill. The environmental and economic impacts of two combined processes, active stage biostabilization + sanitary landfill (AL), and active and curing stage biostabilization + sanitary landfill (ACL), were compared with sanitary landfill (SL) for MSW with high moisture content. The results indicated that land requirement, leachate generation, and CH(4) emission in the ACL process decreased by 68.6%, 89.1%, and 87.6%, respectively, and the total cost was reduced by 24.1%, compared with SL. This implies that a combined biostabilization and landfill process can be an environmentally friendly and economically feasible alternative to landfill of raw MSW with high moisture content. Sensitivity analysis revealed that treatment capacity and construction costs of biostabilization and the oxidation factor of CH(4) significantly influenced the costs and benefits of the AL and ACL process at an extremely low land price. When the land price was greater than 100 USD m(-2), it became the dominating factor in determining the cost of treatment and disposal, and the total costs of ACL were reduced to less than 40% of those of SL.


Asunto(s)
Biodegradación Ambiental , Conservación de los Recursos Naturales/métodos , Desecación , Ambiente , Eliminación de Residuos/métodos , Agua , Amoníaco , Ciudades , Conservación de los Recursos Naturales/economía , Oxidación-Reducción , Eliminación de Residuos/economía , Estados Unidos
17.
Environ Technol ; 32(11-12): 1269-77, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21970169

RESUMEN

With a preliminary insight into the source and leaching behaviour ofbisphenol A (BPA) from municipal solid wastes (MSW), five kinds of plastic and four kinds of paper materials were leached by distilled water. Polyvinyl chloride (PVC) waste was found to have the highest BPA content of 12.1 microg x g(-1) and leachability of 34.7% in distilled water, while cardboard with relatively low BPA content also showed a high ratio of leaching (53.6%). Fresh leachate and leachates from a landfill of age 1.5 and 10 years were adopted as leachants for the PVC plastic and cardboard to simulate the leaching behaviour of BPA under a landfill environment. The enhancement of BPA leachability in the 10-year leachate compared with distilled water was higher than that in the other two leachates due to its basic pH and high content of humic organic matters. Meanwhile, the enhancement of BPA leachability by the fresh leachate was higher than that by the 1.5-year leachate, possibly due to the presence of small molecules such as volatile fatty acids, amino acids, etc. The paper waste was not only a minor origin of BPA leaching, but also a controlling factor in retarding BPA transformation. The BPA sorption K(f) value of the cardboard in the Freundlich equation was 0.2224 mg(1-n)) x L(n) x g(-1) (n = 0.7680), higher than that obtained in sorption experiments by natural organic adsorbents such as sediment. It suggested that the presence of paper with a high sorption capacity in MSW will restrain BPA transport and bioavailability in landfills.


Asunto(s)
Residuos de Alimentos , Fenoles/química , Contaminantes Químicos del Agua/química , Adsorción , Compuestos de Bencidrilo , Concentración de Iones de Hidrógeno , Papel , Fenoles/análisis , Plásticos/química , Cloruro de Polivinilo/química , Factores de Tiempo , Agua/química
18.
Waste Manag Res ; 29(4): 406-13, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20630943

RESUMEN

Biostabilization prior to landfilling of municipal solid waste (MSW) has been developed to reduce leachate pollution and increase landfill capacity and stability. Leaching tests were used in this study to examine the effect of biostabilization on the release potential and fate of heavy metals in MSW. The speciation of heavy metals in leached MSW and leachates, and their distribution in different molecular weight (MW) fractions of organic matter in leachate were studied. The results showed that a 44-day biostabilization period could lower the release potential of Pb, Cr, Cd, Cu, and Zn in MSW by 50 to 84%. With the exception for Zn, biostabilization tended to decrease the percentages of the metals in the leachate organic fraction with MW < 1 kDa, but increase those of metals associated with organic colloids and high-MW fractions. Therefore, the effects of biostabilization on the behaviour and fate of Pb, Cr, Cd and Cu in leachate would vary in treatment facilities that use different methods and in the natural environment. Biostabilization only slightly affected the behaviour and fate of Zn, due to an insignificant variation in the speciation and distribution of Zn in different MW fractions. In addition, the aerobic and hydrolytic-aerobic biostabilization processes showed similar release potential, speciation, and distribution of heavy metals in different MW fractions.


Asunto(s)
Metales Pesados/análisis , Eliminación de Residuos/métodos , Contaminantes Químicos del Agua/análisis , Aerobiosis , Biodegradación Ambiental , Coloides/análisis , Coloides/metabolismo , Metales Pesados/metabolismo , Contaminantes Químicos del Agua/metabolismo
19.
Huan Jing Ke Xue ; 42(9): 4500-4509, 2021 Sep 08.
Artículo en Zh | MEDLINE | ID: mdl-34414750

RESUMEN

Loess is widely distributed in northwestern China. Due to the arid climate and rainstorm erosion, lack of nutrients and microorganisms, as well as severe salinization limits the ecosystem carrying capacity of loess soil, which has become one of the major causes of regional land desertification. The fermentation broth derived from food waste usually contains substantial organic acids and nutrients such as nitrogen and phosphorus, and it has the advantages of being easily produced industrially and applied as fertilizer. Hence, this broth has the potential to become a soil amendment for loess soils. This work studied the Lanzhou loess, which is a typical soil of the Loess Plateau of China, fertilized with fermentation broth for the evaluation of physicochemical properties and microbial analyses. After the application of the broth amendment, the total nitrogen, available phosphorus and potassium, and organic matter content increased by 363%, 577%, 308%, and 204%, respectively. After planting grass, including Halogeton arachnoideus Moq. and Medicago sativa L., the comprehensive soil fertility level was further improved and the total salt content of the soil was decreased by 2.3 g·kg-1 and 1.2 g·kg-1, respectively. Meanwhile, the fermentation broth promoted the growth of microorganisms, including bacteria and archaea, which increased by 22 times, and fungi by 8.3 times. Therefore, food waste fermentation broth is conducive to further forming plant-microorganisms symbiosis, improving the ecological environment quality of loess soils.


Asunto(s)
Eliminación de Residuos , Suelo , Conservación de los Recursos Naturales , Ecosistema , Fermentación , Alimentos
20.
Sci Total Environ ; 772: 145309, 2021 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-33578147

RESUMEN

The explosive growth of polyethylene terephthalate (PET) wastes has brought serious pollution to the environment. Here, PET waste was upcycled into methane-rich pyrolysis gas and carbon material for energy storage through autogenic pressure pyrolysis and post-activation. The pyrolysis gas contained 34.58 ± 0.23 vol% CH4. After CO2 removal, the high caloric value of the pyrolysis gas could reach 29.2 MJ m-3, which could be used as a substitute natural gas. Pyrolytic carbon was further activated by KOH and ZnCl2. KOH-activated carbon (AC-K) obtained a hierarchical porous structure, a high specific surface area of 2683 m2 g-1 and abundant surface functional groups. Working as supercapacitor electrodes, AC-K exhibited an outstanding specific capacitance of 325 F g-1 at a current density of 0.5 A g-1. After 5000 charge-discharge cycles, AC-K still retained 91.86% of the initial specific capacitance. This study provides a sustainable way to control plastic-derived pollution and alleviate the energy crisis.

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