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1.
Chemosphere ; 262: 127924, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32805661

RESUMO

Cr(VI) compounds at high temperature usually tend to decompose and reduce into Cr(III) due to thermodynamically instability for Cr(VI). This study found Cr(VI) could be reduced into Cr(V) instead of Cr(III) in the presence of CaO during heating solid waste containing Cr(VI). CaCrO4 is prepared and mixed with CaO as simulated solid waste containing Cr(VI). It was found that CaCrO4 reacted with CaO and formed a new product Ca5(CrO4)3O0.5 at temperature range of 800 and 1000 °C. The valence state of Cr in Ca5(CrO4)3O0.5 is determined to be +5 b y XPS analysis, and the color for new formed Cr(V) is observed in green, similar to Cr(III) compounds. The temperature and CaO are two keys to arouse the reduction reaction of Cr(VI) into Cr(V). In particular, the reduction of Cr(VI) into Cr(V) is strongly depended on temperature (800-1000 °C), this reaction can be balanced within 10 min, while prolonging sintering time has little help for promoting the reduction of Cr(VI) to Cr(V). Additionally, it was found Cr(V) can keep stable and not be re-oxidized into Cr(VI) at 800-1000 °C. Above results offers some new understanding and knowledge about the formation of Cr(V) in presence of much CaO or CaCO3 during heating solid waste containing Cr(VI).


Assuntos
Cromo/química , Eliminação de Resíduos/métodos , Hidróxido de Cálcio/química , Calefação , Temperatura Alta , Oxirredução , Resíduos Sólidos , Temperatura
2.
An Acad Bras Cienc ; 92(3): e20180972, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33175012

RESUMO

This study was undertaken to investigate the performance, carcass characteristics, and economic viability of diets including pasta waste in meal form (PWM) for quail. A total of 450 unsexed meat quail (Coturnix coturnix coturnix) were distributed into five treatments (0, 10, 20, 30, and 40% inclusion of PWM) in a completely randomized design with six replicates, each with 15 birds. The following rearing periods were evaluated: Phase 1 - 1 to 21 days; and period of 1 to 42 days. In Phase 1, the PWM levels did not influence feed intake (FI), and the PWM inclusion levels for optimal weight gain (WG) and feed conversion (FC) were estimated at 20.70% and 22.8%, respectively. In the cumulative period of 1 to 42 days, the PWM levels did not lead to differences in FI, WG, or FC. The yields of carcass and cuts were not influenced by the treatments; however, abdominal fat yield decreased as the PWM levels in the diets were increased. Economic analysis showed a reduction of the feeding cost in the studied phases. Pasta waste meal can be included up to the level of 40% without incurring losses in the performance or carcass yield of meat quail.


Assuntos
Ração Animal , Fenômenos Fisiológicos da Nutrição Animal , Codorniz , Ração Animal/análise , Animais , Coturnix , Dieta/veterinária , Carne/análise , Resíduos Sólidos
3.
Bioresour Technol ; 318: 124270, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33099102

RESUMO

A simple biorefinery aimed at producing both biomethane (CH4) and polyhydroxyalkanoates (PHAs), was proposed to valorize the organic fraction of municipal solid waste (OFMSW). Anaerobic digestion (AD) was tested at different organic loading rates (OLR-I-II-III) (i.e. 3, 4 and 6 g L-1 d-1, respectively), producing biomethane and volatile fatty acids (VFAs)-rich digestate, the VFAs were then used to produce PHAs. Specific biogas and CH4 production remained similar when adopting different OLRs (biogas of 522-600 NL kg-1 VS and CH4 of 64-67% v/v). VFAs concentrated with OLR increases and their patterns were modified. PHA production was in the range of 117-199 g kg-1 OFMSWTS with the lowest production being associated to different polymer composition. The net energy recovery of this simple biorefinery accounted for 64% of OFMSW energy content, and the PHAs produced represented over 30% of the total energy.


Assuntos
Poli-Hidroxialcanoatos , Eliminação de Resíduos , Anaerobiose , Biocombustíveis/análise , Reatores Biológicos , Metano , Resíduos Sólidos/análise
4.
Sci Total Environ ; 748: 142462, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33113680

RESUMO

The present study was aimed to demonstrate a semi-commercial biomethanation plant based on anaerobic gas lift reactor (AGR) for the mono and co-digestion of organic fraction of municipal solid waste (OFMSW) and landfill leachate (LL) for 47 weeks. The reactors were commissioned at a volatile organic loading rate (VOLR) starting from 0.4 to 6.2 kg VS/(m3·day) to investigate the impact of VOLR on the organic matter removal rates, substrate utilization rate using Stover-Kincannon reaction kinetics, biogas yield and microbial diversity. 16s-metagenomic sequencing of the species present in the inoculum that was acclimatized with OFMSW, LL separately and in combination was also performed to identify the dominant microbial species in the mixed microbial consortia. Results revealed that the VS reduction in AGR 1, AGR 2 and AGR 3 at full load was 46%, 42% and 47% respectively with a corresponding biogas generation of 73.8 m3/day, 42 m3/day and 60.8 m3/day. The biodegradability in AGR 1 was between 73% and 81% whereas in AGR 2 and AGR 3, it was between 57% and 78% and 64% and 86% respectively. The operational strategy of digestate recirculation facilitated in the reduced usage of buffering chemicals which impacted on overall financials of the plant. The techno-economic analysis suggests that these kinds of biomethanation plants are remunerative.


Assuntos
Eliminação de Resíduos , Poluentes Químicos da Água , Anaerobiose , Biocombustíveis/análise , Reatores Biológicos , Cinética , Metano , Resíduos Sólidos/análise
5.
Environ Monit Assess ; 192(11): 682, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-33030635

RESUMO

Sanitary waste disposal and site selection for establishing landfills are challenging problems for environmental planners. This paper aims to take environmental, socio-economic, geological, geomorphological, hydrological and ecological factors into consideration to provide a decision support framework for landfill siting. Analytical hierarchy process (AHP) and Decision Making Trial and Evaluation Laboratory (DEMATEL) are coupled to develop an efficient multi-criteria decision-making method to be utilized in a Geographic Information System (GIS) environment for evaluating the suitability for landfill siting. As the first attempt to employ DEMATEL effectively in a landfill site selection problem, the proposed method is tested with landfill siting scenarios in New South Wales (NSW), Australia. Regional analysis is also performed to identify the potentially most suitable statistical divisions for landfill siting in NSW. The top two ranked zones covering 0.7% and 22% of the study area, respectively, are considered as the optimal areas for establishing landfills, while the bottom two ranked zones are not recommended for further consideration. Further detailed analysis is also conducted on the existing landfills, which shows that 1.0% and 37.0% of them are ranks 1 and 2, respectively. The scenario-based analysis implies that, among the contributing factors; geological and economic factors are highly important.


Assuntos
Técnicas de Apoio para a Decisão , Resíduos Sólidos , Austrália , Monitoramento Ambiental , New South Wales , Instalações de Eliminação de Resíduos
6.
Environ Monit Assess ; 192(11): 690, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33034731

RESUMO

Urbanization is occurring globally at an unprecedented rate. The byproduct of this mounting urbanization is an increase in municipal solid waste (MSW), which has a significant effect on population health and the surrounding environment. This trend poses a challenge to the cities responsible for managing waste in a socially and environmentally acceptable manner. Effective waste management strategies depend on local waste characteristics, which vary under different cultural, climatic, and socioeconomic conditions. It is important to note that MSW disposal represents one of the largest sources for anthropogenic greenhouse gas (GHG) emissions. This study found a direct proportional urban and rural gradient between household income and GHG emissions under a typical urban household size. The distribution of GHG is U-shaped. This study found that urbanization exhibited a pattern of continuous growth, and the effect of urbanization was less than the effect of the population in magnitude. The correlation between GHG and income level in recent urban sprawl along a north-south transect was lower than during the period of early urban expansion.


Assuntos
Gases de Efeito Estufa , Gerenciamento de Resíduos , China , Cidades , Monitoramento Ambiental , Efeito Estufa , Resíduos Sólidos , Urbanização
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5794-5797, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019291

RESUMO

Waste auditing is important for effectively reducing the medical waste generated by resource-intensive operating rooms. To replace the current time-intensive and dangerous manual waste auditing method, we propose a system named iWASTE to detect and classify medical waste based on videos recorded by a camera-equipped waste container. In this pilot study, we collected a video dataset of 4 waste items (gloves, hairnet, mask, and shoecover) and designed a motion detection based preprocessing method to extract and trim useful frames. We propose a novel architecture named R3D+C2D to classify waste videos by combining features learnt by 2D convolutional and 3D convolutional neural networks. The proposed method obtained a promising result (79.99% accuracy) on our challenging dataset.Clinical Relevance-iWaste enables consistent and effective real-time monitoring of solid waste generation in operating rooms, which can be used to enforce medical waste sorting policies and to identify waste reduction strategies.


Assuntos
Resíduos de Serviços de Saúde , Redes Neurais de Computação , Projetos Piloto , Resíduos Sólidos , Gravação em Vídeo
8.
J Environ Sci (China) ; 98: 143-150, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33097146

RESUMO

The nuisance from odor caused by municipal solid waste (MSW) is resulting in a growing number of public complaints and concerns. Odor pollution occurs in the initial decomposition stage of MSW, including waste collection, transportation and early pre-treatment. Furthermore, decomposition takes place in waste facilities that are often close to living areas, which can result in odor impacts on local inhabitants. However, this aspect of odor impact from MSW has not been well studied. In the current study, lab-scale waste cells were designed to simulate MSW storage conditions in the early stage. The characteristics of VOCs emissions with different waste compositions were analyzed. The odor concentration (CO, non-dimensional) method and odor intensity were used for the assessment of odor. Ethanol was the substance with highest emission rate. The release rate of VOCs increased with the growth easily biodegradable waste (EBW). VOCs emissions was reduced by 25% when the proportion of EBW decreased from 60% to 45%. Methyl sulfide, ethanol, dimethyl disulfide and ethyl acetate were identified as typical odorants. The EBW proportion in waste is the main factor significantly influencing odor pollution. The CO was 244.51 for the 60% EBW condition, which was only 61.46 for 15% EBW condition. These study results provide important information for the implementation of a garbage sorting policy and the monitoring of odor pollution from waste management.


Assuntos
Poluentes Atmosféricos , Eliminação de Resíduos , Gerenciamento de Resíduos , Poluentes Atmosféricos/análise , Odorantes/análise , Resíduos Sólidos/análise
9.
Waste Manag ; 118: 637-646, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33011541

RESUMO

Over the last two decades, Barcelona has implemented a far-reaching reform of the city's solid waste collection. In 2000, the city was divided in four zones, with four separate solid waste collection contracts being awarded to private firms, with none being allowed to obtain more than two zones, a rule that was revised in 2009 to just one contract per firm. This division of the market via exclusive territories sought to enhance competition in the expectation of the convergence of relative costs, efficiency and service quality throughout the city. This study analyzes and evaluates the creation of lots as a tool of competition with monthly observations of costs and outputs between 2015 and 2019. Main findings are that firms producing in larger zones report higher costs, that increased competition was not sufficient to lead to converging costs, and that none of the firms operate under increasing returns to scale. Based on our results, we recommend creating an additional zone. We further suggest that if a public firm managed one of the zones, the regulator would obtain more reliable information on the service costs and technical characteristics, thus increasing her capabilities as supervisor of the private firms delivering the service in other zones.


Assuntos
Resíduos Sólidos , Cidades , Custos e Análise de Custo , Resíduos Sólidos/análise
10.
Chemosphere ; 261: 128107, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33113668

RESUMO

Although fluorescent lamps (FL) are extensively used worldwide, recycling rates in some countries are still low. If disposed of inappropriately and broken, FL can cause soil contamination. Hg toxicity in FL is extensively discussed in the literature; however, few studies address the other toxic metals present in the phosphorous powder of FL (PPFL). This paper presents a characterization of the environmental mobility with sequential extraction scheme (SES) of Cd, Cu, Hg, Mn, Ni, Pb, and Zn in PPFL, and modeling the potential risks to human health, in case of direct disposal in soils. An after thermal treatment waste was used for safety reasons. The SES method included five fractions, and the quantification was performed by flame atomic absorption spectrometry (FAAS). Human health risk assessment (HHRA) was conducted using RISC4® software. The PPFL showed the following mobility sequence: Cu (85%) > Ni (81%) > Hg (80%) > Zn (77%) > Cd (75%) > Mn (6%) > Pb (2%), which suggests that Cu, Ni, Zn, and Cd, besides Hg, could be of environmental concern in terms of availability. HHRA showed the potential hazard of Cd, for both children and adults, in the hypothetical scenario of vegetable ingestion, considering vegetables grown in soils contaminated with FL waste. The thermal treatment does not completely remove Hg from the matrix, and the residual Hg still poses a risk to children. These results show that Hg and Cd can be hazardous to humans and reinforce the importance of the correct disposal and treatment of PPFL.


Assuntos
Cádmio/toxicidade , Equipamentos e Provisões Elétricas , Monitoramento Ambiental/métodos , Mercúrio/toxicidade , Poluentes do Solo/toxicidade , Resíduos Sólidos , Adulto , Cádmio/análise , Criança , Humanos , Mercúrio/análise , Fósforo/química , Medição de Risco , Solo/química , Poluentes do Solo/análise , Verduras/química
11.
Bioresour Technol ; 318: 124038, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32889125

RESUMO

This study outlines the entire process chain related to an industrial-sized hydrothermal carbonization (HTC) plant, which treats the organic fraction of municipal solid waste. A parameter study, carried out in laboratory-scaled experiments, was used to create a model starting with the substrate preparation and ending with the production of electricity. It was designed to be infinitely variable with respect to different reaction intensities within certain boundary conditions. Contrary to previous research endeavors, all components related to the HTC process and modules for the post-treatment of co-products including heat recovery and process water treatment were integrated. Based on this model, the claim that HTC-char is a more environmentally friendly energy carrier than lignite was investigated. In the realm of a life cycle assessment, a GWP of 0.45-0.70 kg CO2,Eq/kWhel was revealed for the electricity production from HTC-char. It, thus, outcompetes the electricity production from lignite (1.05-1.40 kg CO2,Eq/kWhel).


Assuntos
Eliminação de Resíduos , Carbono , Eletricidade , Temperatura Alta , Resíduos Sólidos/análise , Temperatura
12.
Environ Sci Pollut Res Int ; 27(34): 43372-43388, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32902753

RESUMO

The study aims to analyze and enhance the eco-efficiency of rice processing in Pakistan while focusing on pollution prevention, waste management, and valorization opportunities. Three rice mills were selected, and physical and chemical properties of their wastewater and solid waste were analyzed. It is depicted that rice husk has the highest share in the solid waste stream and possesses a significant renewable energy potential with a calorific value of 16 MJ/kg and a much lower energy cost of about 0.4 USD/MJ as compared to diesel and furnace oil, i.e., 36.8 and 26.2 USD/MJ, respectively. Recovery of commercially valuable by-products from the effluent of parboiling process is also investigated, and about 0.25 kg of starch/L from wastewater has been effectively reclaimed by wet milling method. The effluent water is also analyzed using Streeter-Phelps model which confirmed that value of contaminants in the wastewater of two of the selected rice mills exceeds the dilution capacity of the receiving body, with dissolved oxygen values at critical level as 0.54 mg/L and -20.7 mg/L respectively. Water pinch analysis and water cascade analysis (WCA) have also been employed to monitor and manage the water footprints. While the concentration composite curve depicted that about 0.8 ton/h of freshwater is saved by an application of smart water integration and pinch point was determined as 1814 ppm. While the WCA confirms that a total water demand of 45.3 kg/s at the third purity level has been reduced to 28.0 kg/s at the lowest purity level.


Assuntos
Oryza , Gerenciamento de Resíduos , Poluentes Químicos da Água , Resíduos Industriais/análise , Paquistão , Resíduos Sólidos , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Poluentes Químicos da Água/análise
13.
Bull Environ Contam Toxicol ; 105(5): 784-789, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32979083

RESUMO

Properly disposing of unused pharmaceuticals is essential to minimize emissions of active pharmaceutical ingredients (APIs). The aim of this study was to determine whether disposing of unused pharmaceuticals in household solid waste is a cost-effective way of attenuating pharmaceutical emissions. We calculated attenuation rates (ARs) for unused pharmaceuticals by performing mass balance calculations for disposal to landfill. The results indicated that the average ARs for disposal as household solid waste reached 63% to 100% for our investigated pharmaceuticals at the worst scenario, indicating that disposal as household solid waste strongly attenuated emissions of APIs. Disposing of unused pharmaceuticals as household solid waste could be a cost-effective disposal method from the view of reducing APIs emission, but should be used with caution.


Assuntos
Preparações Farmacêuticas/análise , Eliminação de Resíduos/métodos , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos , China
14.
Environ Monit Assess ; 192(9): 608, 2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32865639

RESUMO

Population growth, which is the main source of the biggest problems of the world today, combined with migration from rural areas to urban centers, causes the urban centers to be even more concentrated. This necessitates the opening of new residential areas in many city centers, but new residential areas are mostly determined by the decisions of local authorities, who may not base their decisions on scientific data. With the wrong area selection, ordinary natural events can be potentially catastrophic. Such events can result in large numbers of casualties and material damage every year. In this study, an example of applying a method for location selection using various parameters has been realized. The study focuses on Bafra, Turkey (the study area). Risk maps were created in terms of floods and overflows; maps of regions and high-voltage power transmission lines that enjoy a protected area status; and maps of regions in terms of biocomfort suitability. As a result of the evaluation made according to these criteria, it is calculated that only 1.96% of the total working area is suitable for use as a residential area. In relevant literature studies, it was observed that the studies related to the selection of residential areas were carried out only depending on a single standard or criterion. Some suggested biocomfort, and others used vulnerability to risks such as landslide, flood, and earthquakes as their main principle. Studies based on multi-criteria were generally used for purposes such as solid waste site selection and determination of the road routes. The study aims to shed light on the multi-criteria method in an attempt to standardize it in regional planning studies and to inspire similar studies in which different criteria can be used to achieve the maximum efficiency.


Assuntos
Monitoramento Ambiental , Crescimento Demográfico , Resíduos Sólidos , Cidades , Inundações , Turquia
15.
Mar Environ Res ; 160: 105042, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32907740

RESUMO

Economic development, coastal population growth, and expansion of tourism-related activities along coastlines have been the leading causes of marine debris pollution worldwide. While the problem of marine debris pollution has been increasingly recognized, there has been limited research on its socioeconomic drivers, primarily due to a paucity of consistent data on debris. The research described here utilizes newly available data from the U.S. National Oceanic and Atmospheric Association (NOAA) on marine debris along eight coastal states of North America to examine the relationship of such debris pollution with socioeconomic variables including population, age, education, and tourism, as well as the mitigating effect of social capital on debris pollution. The results indicate that marine debris increases with income; however, at higher income levels the amount of pollution starts to decline, supporting the "Environmental Kuznets" hypothesis. We also find that population growth along coastlines contributes to greater debris accumulation. Our results further highlight the significant roles social capital and education play in curbing debris pollution. Understanding the socioeconomic drivers of marine debris is an important first step in informing abatement policy and allocation of resources by public agencies to address the marine pollution problem.


Assuntos
Monitoramento Ambiental , Fatores Socioeconômicos , Resíduos Sólidos , Resíduos , Poluentes da Água , América do Norte , Oceanos e Mares
16.
Waste Manag Res ; 38(10): 1161-1175, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32907525

RESUMO

Quantification, measurement of quality, post-treatment, and leachate control has been a significant problem due to the dumping of waste in an unscientific manner across the globe, and especially in developing countries like India. In this context, the objective of this study was to investigate the degradation of fresh mixed municipal solid waste (MSW) in an anaerobic landfill reactor operated with rainfall addition in laboratory conditions. Experiments were carried out in a landfill reactor of 1 m length × 1 m width × 1.1 m height. The reactor was simulated with 50 years weighted average actual rainfall rate of India. It contained the waste composition of 73% wet waste (food and kitchen) and 27% dry waste (paper, plastic, wood, textiles, and others). The leachate parameters were continually monitored for 39 weeks. In the fresh MSW landfill reactor it was evident that concentrations of leachate parameters were high initially, and there was a significant decrease in BOD5 (7041-39310 mg L-1), COD (15692-71630 mg L-1) and TS (9077-33200 mg L-1) in leachate. Therefore, rainfall had a direct influence on leachate quality. The developed first-order decay models were used for BOD5, COD, and total solids with adjusted R2 of 0.83, 0.92, and 0.96, respectively. Therefore, this model can be applied for leachate strength estimation at any given time from the period of deposition of waste under similar rainfall and waste compositions, and is largely applicable in India and tropical areas. This study is expected to be a good simulation for cities with the waste composition of high wet waste (>70%) as the estimations of important design parameters such as BOD5, COD, VFA, and NH4+-N were studied in this research. As the importance of moisture (precipitation) has been established in this study, some moisture additions can be designed in areas with low rainfall, such as arid zones.


Assuntos
Eliminação de Resíduos , Poluentes Químicos da Água , Anaerobiose , Reatores Biológicos , Índia , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos , Poluentes Químicos da Água/análise
17.
Waste Manag Res ; 38(10): 1153-1160, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32907527

RESUMO

The performances of an integrated system based on mechanical biological treatment and bioreactor landfill with leachate recirculation for managing the mixed municipal solid waste generated in a given Italian district were investigated. In the mechanical biological treatment the municipal solid waste was mechanically sorted into two main streams: a dry and a mechanically sorted organic fraction consisting of 45,000 tonnes year-1. After being sorted the mechanically sorted organic fraction was aerobically pretreated before being disposed of in the 450,000 m3 bioreactor landfill. Experimental runs showed that an aerobic pretreatment period ranging from 15 to 30 days was able to maximize the methane generated by the mechanically sorted organic fraction once landfilled up to 10 Nm3 tonne-1. The aerobic pretreatment leads to a significant volatile solids reduction in the first 30 days, after which the volatile solids concentration remained quite constant. Similarly the potential dynamic respirometer index was significantly reduced in the first 15 days of the aerobic pretreatment decreasing from about 5,000 to about 3,500 mgO2kgVS-1h-1. The whole amount of electrical energy producible by the landfill ranged from 18.5 kWh tonne-1 to 21 kWh tonne-1, depending on the strategies adopted for the activation in bioreactor mode of each landfill cell by the leachate recirculation.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Reatores Biológicos , Itália , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos
18.
Ecotoxicol Environ Saf ; 205: 111317, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32950807

RESUMO

Electrolytic manganese residue (EMR) is a solid waste remained in filters after using sulfuric acid to leaching manganese carbonate ore. EMR contains high concentration of soluble manganese (Mn2+) and ammonia nitrogen (NH4+-N), which seriously pollutes the environment. In this study, a low cost of phosphate based binder for Mn2+ and NH4+-N stabilization in EMR by low grade-MgO (LG-MgO) and superphosphate was studied. The effects of different types of stabilizing agent on the concentrations of NH4+-N and Mn2+, the pH of the EMR leaching solution, stabilizing mechanisms of NH4+-N and Mn2+, leaching test and economic analysis were investigated. The results shown that the pH of the EMR leaching solution was 8.07, and the concentration of Mn2+ was 1.58 mg/L, both of which met the integrated wastewater discharge standard (GB8978-1996), as well as the concentration of NH4+-N decreased from 523.46 mg/L to 32 mg/L, when 4.5 wt.% LG-MgO and 8 wt.% superphosphate dosage were simultaneously used for the stabilization of EMR for 50 d Mn2+ and NH4+-N were mainly stabilized by Mn3(PO4)2·2H2O, MnOOH, Mn3O4, Mn(H2PO4)2·2H2O and NH4MgPO4·6H2O. Economic evaluation revealed that the treatment cost of EMR was $ 11.89/t. This study provides a low-cost materials for NH4+-N and Mn2+ stabilization in EMR.


Assuntos
Amônia/química , Manganês/química , Amônia/análise , Carbonatos , Eletrólise , Eletrólitos/química , Poluentes Ambientais/análise , Manganês/análise , Nitrogênio/análise , Fosfatos/química , Resíduos Sólidos/análise , Águas Residuárias/química
19.
Waste Manag ; 118: 45-54, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32889233

RESUMO

Co-processing of lignocellulosic wastes, e.g., garden and paper wastes, and the organic matters fraction of municipal solid waste (OMSW) in an integrated bioprocess is a possible approach to realize the potential of wastes for biobutanol production. Dilute acid pretreatment is a multi-functional stage for breaking the recalcitrant lignocellulose's structure, hydrolyzing hemicellulose, and hydrolyzing/solubilizing starch, leading to a pretreated solid and a rich hydrolysate. In this study, dilute-acid pretreatment of the combination of wastepaper and OMSW, composite I, as well as garden waste and OMSW, composite II, at severe conditions resulted in "pretreatment hydrolysates" containing 33.7 and 19.4 g/L sugar along with 18.9 and 33.2 g/L soluble starch, respectively. In addition, the hydrolysis of solid remained after the pretreatment of composite I and II resulted in "enzymatic hydrolysates" comprising 19.4 and 33 g/L sugar, respectively. The fermentation of the pretreatment hydrolysates and enzymatic hydrolysates resulted in 3.5 and 6.4 g/L ABE from composite I and 15 and 5.2 g/L ABE from composite II, respectively. In this process, 148 and 173 g ABE (60 and 100 g gasoline equivalent/kg) was obtained from each kg composite I and composite II, respectively, where co-processing of OMSW with lignocellulosic wastes resulted in 10 and 49% higher ABE than that produced from the individual substrates.


Assuntos
Butanóis , Resíduos Sólidos , Fermentação , Hidrólise , Lignina/metabolismo
20.
Waste Manag ; 118: 131-138, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32892090

RESUMO

The preparation of lightweight aggregate (LWA) by high-temperature sintering is a promising method for recycling solid waste safely, especially for solidifying heavy metals effectively. The main aim of this research was to systematically evaluate the effects of the flux components on LWA, including Na2O, MgO, CaO, and Fe2O3. The physical properties and chromium solidification mechanism of LWA were characterized and analyzed. The results showed that the addition of Na facilitated LWA preparation and Cr solidification, whereas Ca, Mg, and Fe were deleterious to some extent. Further analysis indicated that increasing the Fe2O3 content was not conducive to the reduction of Cr because its decomposition reaction creates an oxygen-rich environment. The results of this research could provide a meaningful guide for regulating the composition of raw materials for the production of LWA to treat industrial Cr-containing solid waste.


Assuntos
Metais Pesados , Esgotos , Temperatura Alta , Metais Pesados/análise , Reciclagem , Resíduos Sólidos
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