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1.
PLoS One ; 18(3): e0282336, 2023.
Article in English | MEDLINE | ID: mdl-36928275

ABSTRACT

Today, the topic of waste separation has been raised for a long time, and some waste separation devices have been installed in large communities. However, the vast majority of domestic waste is still not properly sorted and put out, and the disposal of domestic waste still relies mostly on manual classification. The research in this paper applies deep learning to this persistent problem, which has important significance and impact. The domestic waste is classified into four categories: recyclable waste, kitchen waste, hazardous waste and other waste. The garbage classification model trained based on MobileNetV2 deep neural network can classify domestic garbage quickly and accurately, which can save a lot of labor, material and time costs. The absolute accuracy of the trained network model is 82.92%. In comparison with CNN network model, the classification accuracy of MobileNetV2 model is 15.42% higher than that of CNN model. In addition, the trained model is light enough to be better applied to mobile.


Subject(s)
Garbage , Neural Networks, Computer , Hazardous Waste
2.
Front Public Health ; 11: 996960, 2023.
Article in English | MEDLINE | ID: mdl-36923045

ABSTRACT

Background and aim: The implementation of idoneous management of hazardous waste, in contrast to illegal practices, is one of the environment and health priorities of the WHO. The aim of the present study, based on a collaborative agreement between the Italian National Health Institute and a Prosecution Office located in Naples North, was to evaluate the health effects of illegal landfills and burning of urban and hazardous waste in the territory of the Prosecution Office. Methods: The municipalities included in the study territory were investigated with respect to the regional population. Regression analyses were performed in the study area between four classes of an environmental municipal indicator of waste risk (MRI) previously defined, computing the relative risks (RRs) in 2-4 MRI classes, with respect to the first MRI class (the least impacted). The prevalence of reproductive outcomes and cause-specific mortality and hospitalization were analyzed in the general population and in the 0-19-year-old population using SAS software. Results: An increase of mortality and hospitalization risk in both the genders of the whole area, with respect to regional population, were found for overall all cancer cases, cancer of the stomach, the liver, the lung and the kidney, and ischemic heart diseases. An increase of mortality for leukemias in the 0-19-year-old population and in hospitalization risk for certain conditions originating in the perinatal period were observed. Correlation between MRI and the risk of mortality from breast tumors in women (MRI class 2: RR = 1.06; MRI class 3: RR = 1.15; MRI class 4: RR = 1.11) and between MRI and the risk of hospitalization from testis tumors (MRI class 2: RR = 1.25; MRI class 3: RR = 1.31; MRI class 4: RR = 1.32) were found. The hospitalization risk from breast tumors and asthma exceeded significantly in both genders of three and four MRI classes. Among the 0-19-year-old population, correlation between MRI and hospitalization from leukemias (MRI class 2: RR = 1.48; MRI class 3: RR = 1.60; MRI class 4: RR = 1.41) and between MRI and the prevalence of preterm birth (MRI class 2: RR = 1.17; MRI class 3: RR = 1.08; MRI class 4: RR = 1.25) were found. Conclusion: A correlation between health outcomes and the environmental pressure by uncontrolled waste sites was found. Notwithstanding the limitation of the study, the results promote implementing the actions of environmental remediation and the prosecution of illegal practices.


Subject(s)
Breast Neoplasms , Leukemia , Premature Birth , Pregnancy , Humans , Male , Female , Infant, Newborn , Infant , Child, Preschool , Child , Adolescent , Young Adult , Adult , Environmental Exposure/adverse effects , Hazardous Waste/adverse effects , Italy/epidemiology , Waste Disposal Facilities , Epidemiologic Studies
3.
Sci Total Environ ; 869: 161732, 2023 Apr 15.
Article in English | MEDLINE | ID: mdl-36682552

ABSTRACT

Ca/Fe-rich antibiotic fermentation residues (AFRs), a type of hazardous waste, can be regarded as recyclable biomass and metal resources. However, concurrent detoxification and reutilization of biomass and metals resources from AFRs have never been reported before. In this study, Ca/Fe-rich vancomycin fermentation residues were pyrolyzed into biochar to adsorb phosphate for the first time. The residual vancomycin and antibiotic resistance genes were completely decomposed during pyrolysis. The resultant Ca/Fe-rich biochar exhibited excellent performance at adsorbing phosphate without further modifications. The process had rapid kinetics and a maximum adsorption capacity of 102 mg P/g. Ca and Fe were the active sites, whereas different mechanisms were observed under acidic and alkaline conditions. Surprisingly, HCO3- enhanced phosphate adsorption with an increase of adsorption capacity from 43.9 to 71.0 mg/g when HCO3- concentration increased from 1 to 10 mM. Furthermore, actual wastewater could be effectively treated by the biochar. The phosphate-rich spent biochar significantly promoted seed germination (germination rate: 96.7 % vs. 80.0 % in control group, p < 0.01) and seedling growth (shoot length was increased by 57.9 %, p < 0.01) due to the slow release of bioavailable phosphate, and thus could be potentially used as a phosphorous fertilizer. Consequently, the hazardous waste was turned into phosphorous fertilizer, with the additional benefits of detoxifying AFRs, reutilizing biomass and metal resources from AFRs, controlling phosphate pollution, and recovering phosphate from wastewater.


Subject(s)
Phosphates , Wastewater , Phosphates/chemistry , Fertilizers , Fermentation , Anti-Bacterial Agents , Pyrolysis , Vancomycin , Hazardous Waste , Phosphorus , Charcoal/chemistry , Adsorption , Kinetics
4.
Environ Pollut ; 321: 121080, 2023 Mar 15.
Article in English | MEDLINE | ID: mdl-36702428

ABSTRACT

Medical wastes include all solid and liquid wastes that are produced during the treatment, diagnosis, and immunisation of animals and humans. A significant proportion of medical waste is infectious, hazardous, radioactive, and contains potentially toxic elements (PTEs) (i.e., heavy metal (loids)). PTEs, including arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg), are mostly present in plastic, syringes, rubber, adhesive plaster, battery wastes of medical facilities in elemental form, as well as oxides, chlorides, and sulfates. Incineration and sterilisation are the most common technologies adopted for the safe management and disposal of medical wastes, which are primarily aimed at eliminating deadly pathogens. The ash materials derived from the incineration of hazardous medical wastes are generally disposed of in landfills after the solidification/stabilisation (S/S) process. In contrast, the ash materials derived from nonhazardous wastes are applied to the soil as a source of nutrients and soil amendment. The release of PTEs from medical waste ash material from landfill sites and soil application can result in ecotoxicity. The present study is a review paper that aims to critically review the dynamisms of PTEs in various environmental media after medical waste disposal, the environmental and health implications of their poor management, and the common misconceptions regarding medical waste.


Subject(s)
Medical Waste Disposal , Medical Waste , Mercury , Metals, Heavy , Refuse Disposal , Animals , Humans , Incineration , Metals, Heavy/analysis , Hazardous Waste/analysis , Solid Waste/analysis
5.
Environ Sci Pollut Res Int ; 30(12): 33877-33885, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36502480

ABSTRACT

This study investigated the influence of the interaction between Fe-based substances and thermal treatment parameters on the leaching behavior of Cr in hazardous waste incineration fly ash (HWIFA) after thermal treatment. The results revealed that the interaction between the addition of Fe-based substance and the thermal treatment parameters and their effects on static and dynamic leaching behaviors of Cr had significant differences when Fe2O3, Fe3O4, and Fe were added, respectively. Specifically, when Fe2O3 or Fe was added, the thermal treatment temperature was the most significant factor affecting the static leaching of Cr in thermal treated HWIFA, and the interaction effect of other factors was not significant. The most important influence on the dynamic leaching behavior of Cr was the interaction between the thermal treatment temperature and the addition of Fe2O3. Different from the addition of Fe2O3, the effect of the addition of Fe3O4 on the static leaching of Cr in thermal treated HWIFA was more significant than that of thermal treatment temperature; meanwhile, the interaction between the thermal treatment temperature and the addition of Fe3O4 was also significant. However, when Fe3O4 was added, the effect of interaction between factors on the dynamic leaching of Cr in thermal treated HWIFA was consistent with that when Fe2O3 was added.


Subject(s)
Metals, Heavy , Refuse Disposal , Incineration , Coal Ash/analysis , Metals, Heavy/analysis , Hazardous Waste , Temperature , Solid Waste/analysis , Carbon , Particulate Matter
6.
J Environ Sci (China) ; 126: 40-47, 2023 Apr.
Article in English | MEDLINE | ID: mdl-36503767

ABSTRACT

Hazardous waste of chemical oxygen demand (COD) test (HWCOD) is one of the most common laboratory wastewaters, containing large amounts of H2SO4 and highly toxic Cr3+ and Hg2+. Current treatment methods suffered from incomplete removal of Cr3+ and high-cost. Herein, a humic acid-coated zirconium oxide-resin nanocomposite (HA-HZO-201) was fabricated for efficient recovery of Cr3+ and Hg2+ in HWCOD. The synthesized HA-HZO-201 shows excellent tolerance to wide pH range (1-5) and high salinity (3.5 mol/L NaCl), as well as adsorption capacity for Cr3+ (37.5 mg/g) and Hg2+ (121.3 mg/g). After treating with HA-HZO-201 by using a fixed-bed adsorption procedure, the final Cr3+ and Hg2+ concentrations in HWCOD decreased to 0.28 and 0.02 mg/L, respectively. In addition, the HA-HZO-201 can be regenerated by desorption and recovery of Cr3+ and Hg2+ using HNO3 and thiourea as eluents, respectively. After 5 cycles of adsorption/desorption, the removal efficiencies still reach up to 86.0% for Cr3+ and 89.7% for Hg2+, indicating an excellent regeneration of HA-HZO-201. We hope this work open new opportunities for treatment of HWCOD with high-efficiency and low-cost.


Subject(s)
Hazardous Waste , Mercury , Humic Substances , Chromium , Biological Oxygen Demand Analysis
7.
J Environ Manage ; 329: 117090, 2023 Mar 01.
Article in English | MEDLINE | ID: mdl-36584517

ABSTRACT

Harmless disposal and resource utilization of hazardous industrial wastes has become an important issue with the green development of human society. However, resource utilization of hazardous solid wastes, such as the production of cementitious materials, is usually accompanied by a pretreatment process to remove adverse impurities that contaminate the final product. In this study, aluminum dross (AD) was thermally co-treated with another hazardous waste, municipal solid incineration fly ash (MSWI-FA), to synergistically solidify F and Na, control leaching of heavy metals, and remove chloride impurities. Significant crusting was observed when AD was thermally treated by itself, but not when AD and MSWI-FA were thermally co-treated. In the process of co-thermal treatment, the remaining Cl, Na, and K contents were reduced to as low as 0.3%, 1.8%, and 0.6%, respectively. CaO and SiO2 in MSWI-FA reacted with Na3AlF6 and Al2O3 in AD, and formed CaF2 and Na6(AlSiO4)6, which contributed to the prevention of crusting and limited the leaching concentrations of F and Na to below detection thresholds and 270.6 mg/L, respectively. In addition, heavy metals were well solidified, and dioxins were fully decomposed during thermal treatment. Finally, a sulfoaluminate cementitious material (SACM) with high early- and later-age strengths was successfully created via synergetic complementarity using thermally co-treated AD and MSWI-FA together with other solid wastes. Collectively, this study outlines a promising method for the efficient and sustainable utilization of AD and MSWI-FA.


Subject(s)
Metals, Heavy , Refuse Disposal , Humans , Incineration/methods , Solid Waste/analysis , Coal Ash , Refuse Disposal/methods , Aluminum , Particulate Matter , Silicon Dioxide , Carbon , Metals, Heavy/analysis , Chlorides , Hazardous Waste
8.
Article in English | MEDLINE | ID: mdl-36232017

ABSTRACT

Solid waste management (SWM) is one of the key responsibilities of city administrators and one of the effective proxies for good governance. Effective SWM mitigates adverse health and environmental impacts, conserves resources, and improves the livability of cities. However, unsustainable SWM practices, exacerbated by rapid urbanization and financial and institutional limitations, negatively impact public health and environmental sustainability. This review article assesses the human and environmental health impacts of SWM practices in the Global South cities that are the future of global urbanization. The study employs desktop research methodology based on in-depth analysis of secondary data and literature, including official documents and published articles. It finds that the commonplace SWM practices include mixing household and commercial garbage with hazardous waste during storage and handling. While waste storage is largely in old or poorly managed facilities such as storage containers, the transportation system is often deficient and informal. The disposal methods are predominantly via uncontrolled dumping, open-air incinerators, and landfills. The negative impacts of such practices include air and water pollution, land degradation, emissions of methane and hazardous leachate, and climate change. These impacts impose significant environmental and public health costs on residents with marginalized social groups mostly affected. The paper concludes with recommendations for mitigating the public and environmental health risks associated with the existing SWM practices in the Global South.


Subject(s)
Garbage , Refuse Disposal , Waste Management , Cities , Hazardous Waste , Humans , Methane , Refuse Disposal/methods , Solid Waste , Waste Disposal Facilities , Waste Management/methods
9.
AMA J Ethics ; 24(10): E959-966, 2022 10 01.
Article in English | MEDLINE | ID: mdl-36215188

ABSTRACT

Health care waste is a global problem. While most health care waste is harmless, some of it is hazardous. The volume of hazardous waste generated worldwide is enormous, and its disposal can be environmentally damaging. This article discusses how such waste disposal is regulated and the problems that currently exist with waste disposal regulation. The article also offers possible national and international regulatory solutions.


Subject(s)
Hazardous Waste , Refuse Disposal , Delivery of Health Care , Hazardous Waste/analysis , Humans
10.
Indian J Med Microbiol ; 40(4): 496-500, 2022.
Article in English | MEDLINE | ID: mdl-36096850

ABSTRACT

PURPOSE: The ongoing COVID-19 crisis has drastically changed the practice of biomedical waste (BMW) generation and management. Studies venturing into the facility level preparedness at various levels of healthcare delivery during pandemic situation is the need of the hour. Hence, we did this study to assess the BMW disposal practices amongst secondary and tertiary health facilities during COVID-19 pandemic in Tamil Nadu. MATERIALS AND METHODS: This cross-sectional survey was conducted amongst doctors, nurses and allied healthcare staffs across various departments in 18 public health facilities across six districts of Tamil Nadu. Multivariable logistic regression analysis was done based on the random-intercept model to assess the determinants of BMW disposal practices. The effect size was reported as adjusted odds ratio (aOR) with 95% confidence interval (CI). RESULTS: In total, 2593 BMW disposal observations were made. During nearly three-fourth of the observations (73%), the BMW was disposed of appropriately. Nurses (aOR â€‹= â€‹1.54; 95%CI: 1.06-2.23) and doctors (aOR â€‹= â€‹1.60; 95%CI: 1.05-2.45), healthcare workers in Paediatrics department (aOR â€‹= â€‹1.77; 95%CI: 1.13-2.76), healthcare workers in inpatient department (aOR â€‹= â€‹2.77; 95%CI: 1.95-3.94) and injection outpatient department (aOR â€‹= â€‹2.69; 95%CI: 1.59-4.47) had significantly better odds of having appropriate BMW disposal practices. CONCLUSION: Our study shows that nearly during three-fourth of the observations, healthcare workers performed appropriate BMW disposal practices. However, measures should be taken to achieve 100% compliance by healthcare workers especially the target groups identified in our study by allocating appropriate resources and periodically monitor the BMW disposal practices.


Subject(s)
COVID-19 , Guideline Adherence , Hazardous Waste , Health Personnel , Medical Waste Disposal , Secondary Care Centers , Tertiary Care Centers , Child , Humans , COVID-19/epidemiology , COVID-19/prevention & control , Cross-Sectional Studies , India/epidemiology , Pandemics , Medical Waste Disposal/methods , Odds Ratio
11.
Environ Res ; 215(Pt 2): 114240, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36103930

ABSTRACT

Biomedical waste from healthcare activities poses a higher hazard of infection and damage than other types of trash. The main objective of the study was to assess the awareness knowledge and practices of biomedical waste management (BMWM) among health care professionals in the health care units. The cross-sectional study was carried out to access the awareness, knowledge and practices of health care professionals for BMWM. Using a qualitative approach, the study was escorted in two Apex hospitals i.e. the Allied Hospital and the District Head Quarter Hospital, Faisalabad, Pakistan from August 5, 2019 to October 15, 2019. More than 90% of respondents knew the phrase BMWM, but just 35.4% had awareness about biomedical waste regulations. About 71.6% of the respondents were familiar with biomedical waste's color-coding segregation. The study concludes gap in the awareness, knowledge and practices for BMWM. The sanitary workers of the hospitals had no knowledge about BMWM and the BMWM/healthcare waste management rule 2005 established in Pakistan due to the lack of training regarding waste management and the segregation process. Some of the staff members were aware of the BMWM practices under the rules and regulations of Pakistan but were unable to implement at their work place. It is necessary to dispose of the biomedical waste according to the established terms and conditions of BMWM rules (2005) of Pakistan. Weak structure of BMWM was observed at the study sites due to the lack of training, liabilities and absence of penalties against improper biomedical waste disposal as violation of the rules and regulations. It's a dire need of the time to consider the biomedical waste as hazardous waste and make policies for its safe disposal and ensure the implementation of the policies in all the medical centers of Pakistan.


Subject(s)
Communicable Diseases , Medical Waste Disposal , Waste Management , Cross-Sectional Studies , Hazardous Waste , Health Personnel , Hospitals , Humans
12.
J Environ Manage ; 322: 116145, 2022 Nov 15.
Article in English | MEDLINE | ID: mdl-36070648

ABSTRACT

Heavy metals (HMs) in mixed hazardous waste can be volatilized in the kiln for preparing sintered bricks, which greatly increases the environmental risk. In this study, the volatilization, transformation, and leaching of HMs from bricks were evaluated. Field tests and laboratory leaching experiments were carried out. HM-contaminated soil was used to prepare sintered bricks at high-temperature in a tunnel kiln. Release of HMs from brick under rainfall conditions was investigated in laboratory simulation experiments. The field tests showed that the total amount of Pb, Zn, Cd distributed to the gas phase were all less than 2%, but the amount of Hg entering the gas phase 40.1%-60.5% in the particulate forms. The As leaching rate increased after sintering of bricks in the kiln, which was attributed to the increased formation of soluble arsenate and the reduced availability of sorption sites. The tank leaching test indicated that the release mechanism of trance elements (Cr, As, Zn, Cd, Pb and Ni) was mainly controlled by diffusion. This study provides useful knowledge for decreasing the volatilization and leaching of HMs from sintered bricks prepared using hazardous waste.


Subject(s)
Mercury , Metalloids , Metals, Heavy , Arsenates , Cadmium , Hazardous Waste , Lead , Metals, Heavy/analysis , Soil
13.
Waste Manag ; 153: 121-128, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36088859

ABSTRACT

Recycling cathode materials from spent lithium-ion batteries has the potential to reduce damages to the environment and human health due to hazardous waste treatment, and mitigate supply risks of raw materials. Related political incentives or regulations have led to increased research and development efforts on cathode recycling. Promising approaches include direct recycling and hydrometallurgical processes, where delamination is the first step after collection of cathodes. In this study, we examined a pressure washing system's ability to harvest cathode materials. A high-pressure water jet provides strong forces to overcome the adhesion provided by organic binders. Four factors (water pressure, distance between nozzle and cathode, incident angle of water jet, and nozzle type) were investigated using a 34-1 fractional factorial design to screen important parameters and find the optimal conditions. Compared with other delamination processes where chemical reagents and heating are involved, the chemical-free pressure washing system can achieve separation in a few seconds (∼74 min/m2) at room temperature, which remarkably improves the efficiency of delamination. The particle size of recycled products (D50 of 31.87 µm) is significantly reduced without Al contamination from current collectors or morphological damages. In addition, three types of recycled cathode materials were used as inputs for the acid leaching process. High leaching efficiencies of lithium (>90 %) and cobalt (>85 %) suggest that the pressure washing system could be a practical, economical, and eco-friendly pretreatment process to harvest cathode materials.


Subject(s)
Electric Power Supplies , Lithium , Cobalt , Electrodes , Hazardous Waste , Humans , Recycling , Water
14.
J Environ Manage ; 322: 116074, 2022 Nov 15.
Article in English | MEDLINE | ID: mdl-36049309

ABSTRACT

Among global efforts facing plastic pollution, their gradual replacement with alternative materials has gained strength during the last decade. We identified five stakeholders and their respective key participation in the chain of bio-based, biodegradable and compostable plastics (BBCP), which have contributed to several flaws on governance of these materials. The widespread unfamiliarity of the consumers about biodegradability concepts has been leading to misguided purchase decisions and disposal practices, along with possible littering behavior. Simultaneously, the adoption of greenwashing practices by stores and manufacturers contribute to disseminating misguided decisions on plastic consumption. Such issues are further aggravated by the lack of certification standards concerning the impact of littering, including the assessment of persistency and toxicity, also covering those made with biodegradable plastics.". Moreover, even though such alternative polymers were originally conceived as a strategy to minimize plastics pollution, the almost inexistence of specific regulatory frameworks in different political scales may convert them in a relevant part of the problem. Therefore, the governance systems and management strategies need to incorporate BBCP as potentially hazardous waste as they do for conventional plastics.


Subject(s)
Biodegradable Plastics , Biodegradation, Environmental , Hazardous Waste , Plastics , Polymers
15.
Waste Manag ; 153: 304-311, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36179549

ABSTRACT

This study investigated the leaching behavior of Pb in hazardous waste incineration fly ash (HWIFA) after adding Fe2O3 thermal treatment and revealed the leaching mechanism of Pb from the perspective of phase transformation. The static leaching results showed that at 600 °C-1300 °C, with the addition of Fe2O3 increased, the Pb leaching toxicity continued to decrease. The dynamic results indicated that as the thermal treatment temperature was higher than 1100 °C, the addition of Fe2O3 can effectively inhibit the dynamic leaching of Pb in HWIFA. Meanwhile, the inhibition effect was not very closely related to the amount of Fe2O3. The addition of Fe2O3 can react with PbO to form PbFe12O19, which has a better stability. The appearance of PbFe12O19 was the main reason for adding Fe2O3 to enhanced the immobilization of Pb. However, the amount of Fe2O3 should be carefully controlled to avoid an excessive reducible fraction of Pb in the thermal treated HWIFA, which will affect the long-term stability of Pb.


Subject(s)
Metals, Heavy , Refuse Disposal , Carbon , Coal Ash/analysis , Hazardous Waste , Incineration/methods , Lead , Metals, Heavy/analysis , Particulate Matter , Solid Waste/analysis
16.
Sr Care Pharm ; 37(10): 488-494, 2022 Oct 01.
Article in English | MEDLINE | ID: mdl-36171663

ABSTRACT

The article provides a summary of changes in the US Environmental Protection Agency's (EPA) regulation of hazardous waste pharmaceuticals as they pertain to both long-term care-provider pharmacies and longterm care facilities. The article describes the EPA's Final Rule: Management Standards for Hazardous Waste Pharmaceuticals and Amendment to the P075 Listing for Nicotine, which became effective in some states on August 22, 2019, and is slowly being adopted by states nationwide. The new rule applies to all health care settings, including provider pharmacies and, for the first time, specifically refers to long-term care facilities as regulated entities. A major benefit of the Final Rule is the removal of over-the-counter nicotine gums, lozenges, and patches from regulation as a P-listed hazardous waste, which previously has had a major negative impact on the hazardous waste generation status of health care facilities. Waste-generation parameters are provided to enable both provider pharmacies and consultant pharmacists to evaluate their specific practices to determine applicability. The biggest change is the removal of all hazardous waste pharmaceuticals from the future calculation of generator status, thereby enabling facilities to meet the requirements of Very Small Quantity Generators or Small Quantity Generators of hazardous waste. All Small Quantity and Large Quantity Generators of hazardous waste must notify their state of their generator status once the state adopts the Final Rule by completing Form 8700-12. This article provides a variety of references to provide The American Society of Consultant Pharmacists members with additional resources and information.


Subject(s)
Refuse Disposal , Waste Management , Hazardous Waste , Humans , Long-Term Care , Nicotine , Pharmaceutical Preparations , United States , United States Environmental Protection Agency
17.
J Environ Manage ; 324: 116246, 2022 Dec 15.
Article in English | MEDLINE | ID: mdl-36162320

ABSTRACT

Hazardous waste incineration fly ash (HFA) is considered a hazardous waste owing to the high associated concentrations of heavy metals and soluble salts. Hence, cost effective methods are urgently needed to properly dispose HFA. In this study, geopolymers were prepared by alkali-activation technology to stabilize and solidify heavy metals in HFA. In addition, the effects of three different aluminosilicates (metakaolin, fly ash, and glass powder) on the heavy metal immobilization efficiency were investigated. Because the soluble salt content of HFA is too high for their direct placement in flexible landfill sites and water washing can lead to heavy metal leaching, water-washing experiments were conducted after alkali-activation treatment to remove soluble salts. The results suggest that the concentrations of heavy metals leached from geopolymers can satisfy the Chinese Standard limits (GB18598-2019) when the addition of aluminosilicates exceeds 20 wt%. More than 77% of Cl- and >64% of SO42- in geopolymers could be removed via water-washing treatment. The Zn leaching concentration was maintained below approximately 0.52 ppm. After alkali-activation treatment, the water-washing process could efficiently remove soluble salts while inhibiting heavy metal leaching. Sodium-aluminosilicate-hydrate (N-A-S-H) gel, a product of the geopolymerization process in this study, was demonstrated to act as a protective shell that inhibited heavy metal leaching. Hence, HFA-based geopolymers are considered suitable for disposal in flexible landfills.


Subject(s)
Metals, Heavy , Refuse Disposal , Incineration/methods , Coal Ash , Hazardous Waste , Salts , Metals, Heavy/analysis , Alkalies , Water , Refuse Disposal/methods , Solid Waste/analysis , Carbon , Particulate Matter
18.
Waste Manag ; 153: 264-274, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36148697

ABSTRACT

Municipal solid waste incineration (MSWI) fly ash and electrolytic manganese residue (EMR) belong to hazardous waste, and must be disposed of before processing. It was found that the low content of silicon and aluminum at low roasting temperature can meet the expansion mechanism of lightweight aggregates. A low-aluminum-silicon lightweight ceramisite was successfully prepared from MSWI fly and EMR, the formation mechanism of which was that the viscosity of molten stuffs in pellet was the function of temperature and chemical composition and had enough capacity of capturing the emerged gas over roasting. The resulting ceramisite met with the requirement of Lytag commercial lightweight aggregate. The content of heavy metal in ceramisite accorded with the requirement of soil environmental quality for development GB 36600-2018 Class I, and PCDD/Fs in ceramisite was 2.0 ng I-TEQ/kg, which was safe. The collaboration of thermal simulation and characterization (SEM-EDS, FTIR and XRD) elaborated the formation mechanism of ceramisite, with six stages provided.


Subject(s)
Metals, Heavy , Polychlorinated Dibenzodioxins , Refuse Disposal , Aluminum , Carbon , Coal Ash/chemistry , Dibenzofurans , Hazardous Waste , Incineration , Ions , Manganese , Metals, Heavy/analysis , Particulate Matter , Silicon , Soil , Solid Waste
19.
Environ Pollut ; 314: 120261, 2022 Dec 01.
Article in English | MEDLINE | ID: mdl-36155219

ABSTRACT

The control of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from the flue gas in hazardous waste incinerators (HWIs) is an intractable problem. To figure out the formation mechanism of PCDD/Fs and reduce the emission, a field study was carried out in a full-scale HWI. Ca(OH)2 & (NH4)H2PO4 or CH4N2S & (NH4)H2PO4 were injected into the quench tower, and the detailed inhibition effect on PCDD/Fs formation by the inhibitors coupled with quench tower was studied. Gas and ash samples were collected to analyze PCDD/Fs. XPS, EDS characterization and Principal component analysis were adopted to further analyze the de novo and precursors synthesis. The PCDD/Fs emissions reduced from 0.135 ng I-TEQ/Nm3 to 0.062 or 0.025 ng I-TEQ/Nm3 after the injection of Ca(OH)2 & (NH4)H2PO4 or CH4N2S & (NH4)H2PO4, respectively. The quench tower was found mainly hindering de novo synthesis by reducing reaction time. CP-route was the dominant formation pathway of PCDD/Fs in quench tower ash. Ca(OH)2 & (NH4)H2PO4 effectively inhibit precursors synthesis and reduce proportions of organic chlorine from 4.11% to 2.86%. CH4N2S & (NH4)H2PO4 show good control effects on both de novo and precursors synthesis by reducing chlorine content and inhibiting metal-catalysts. Sulfur-containing inhibitors can cooperate well with the quench tower to inhibit PCDD/Fs formation and will be effective to reduce dioxins formation in high chlorine flue gas. The results pave the way for further industrial application of inhibition to reduce PCDD/Fs emissions in the HWIs flue gas.


Subject(s)
Air Pollutants , Benzofurans , Dioxins , Polychlorinated Dibenzodioxins , Hazardous Waste/analysis , Dibenzofurans/analysis , Polychlorinated Dibenzodioxins/analysis , Dioxins/analysis , Chlorine/analysis , Air Pollutants/analysis , Benzofurans/analysis , Environmental Monitoring , Incineration/methods , Sulfur/analysis , Dibenzofurans, Polychlorinated/analysis
20.
J Air Waste Manag Assoc ; 72(10): 1121-1136, 2022 10.
Article in English | MEDLINE | ID: mdl-35939657

ABSTRACT

This study proposed a decision support system (DSS) for optimizing transportation routing and disposal hub location for Thailand's local administrative organizations' hazardous waste management. The first step is to choose the origin and destination, as well as to collect data for each route. Each route's decision criteria were based on traffic quality and risk measures from the perspective of users. An analytic hierarchy process (AHP) was used to compute effective weights for decision criteria. To achieve optimal routing, AHP weights were combined with a zero-one goal programming technique. The DSS operates systematically and successfully, taking into account both transportation risk and socioeconomic factors, and provides appropriate routes. Overall, this waste management system may provide useful information to decision-makers for prioritizing disposal site alternatives and implementing feasible waste management actions. The zero-one location design was then used to determine the best hub location. Based on two scenarios of six and fifteen CoG hubs, the results revealed that the best model for managing a case company's hazardous waste was to establish 15 hubs scattered throughout the country for collecting points and then transporting them to the waste disposal plant in Phitsanulok province. Locating the hub near sink points would reduce transportation costs and backhaul issues, reducing the environmental impact of GHG emissions and increasing system efficiency.Implications: The problem of waste pollution has become increasingly serious all over the world, particularly in developing countries that face significant pollution control challenges. End-of-life wastes cause economic, health, and environmental problems if they are not properly managed. As the world's population and living standards rise, so does the amount of waste produced. The environmental impact is significant, with massive amounts of waste generated each year with only basic or minimal treatment to mitigate its impact. As a result, there is an urgent need for a method that can precisely optimize transportation routing and disposal hub location for Thailand's local administrative organizations' hazardous waste management (LAOs). The proposed decision support system (DSS) may provide useful information to decision-makers in prioritizing disposal site alternatives and implementing feasible waste management actions.


Subject(s)
Refuse Disposal , Waste Management , Hazardous Waste/analysis , Refuse Disposal/methods , Thailand , Transportation , Waste Management/methods
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