Domestic waste incineration slag(WIS)includes fly ash and slag.Fly ash is classified as hazardous waste because it contains heavy metals.Most of slag are directly stacked or landfilled due to problems such as large ou...Domestic waste incineration slag(WIS)includes fly ash and slag.Fly ash is classified as hazardous waste because it contains heavy metals.Most of slag are directly stacked or landfilled due to problems such as large output and low utilization rate.Harmless treatment is imminent.If WIS is used effectively in the road engineering,which can realize the high-quality and high-efficiency recycling of WIS,and it is of great significance to save resources and protect the environment.This study applies a geopolymer prepared from WIS fly ash as a stabilizing agent in WIS blending macadam for use as a pavement base mixture,and reports the mechanical properties(unconfined compressive strength,splitting strength,and resilience modulus)of the geopolymer-stabilized WIS blending macadam(GeoWIS).The leaching concentrations of harmful heavy metals of GeoWIS soaked in water were also investigated.Finally,the strength formation and heavy metal stability mechanisms were explored.The unconfined compressive strength,splitting strength,and compressive resilient modulus of GeoWIS all increased with increasing geopolymer content and decreasing WIS content.The strength of GeoWIS was derived from its geopolymerization and hydration products(C-S-H gel,N-A-S-H gel,and AFt).When the geopolymer content reached 12%–14%,the GeoWIS without natural macadam met the strength criterion of the asphalt pavement base.Through physical adsorption and chemical bonding,the geopolymer significantly reduced the leaching of harmful heavy metals.In GeoWIS with 50%WIS and stabilized with 10%geopolymer,the Cr,Ni,Cd,and Pb concentrations met the grade III groundwater standard.Concentrations of heavy metals leached from GeoWIS are low and exert little impact on environment.展开更多
This paper provides analytical diagnosis of mechanical conditions of medical waste incinerators used for healthcare waste (HCW) treatment in Tanzania. The main features assessed were types of incinerators, features of...This paper provides analytical diagnosis of mechanical conditions of medical waste incinerators used for healthcare waste (HCW) treatment in Tanzania. The main features assessed were types of incinerators, features of incinerators and incinerator house. The assessment was conducted in three levels of health care facilities (HCFs), that is, Regional, district hospitals and health centers, existed in 26 regions of Tanzania. Questionnaires, interview and checklists were used as tools for data collection. It was observed that High-Tech incinerators are mainly used in regional hospitals, while district hospital and health center use both High-Tech and De-Montfort incinerators. About 60% of the incinerators have defective doors. More than 55% of incinerators are corroded in regional and district hospitals. The chimney, top plates and grate which are good condition are 55.6% and 60% in regional hospitals and health centers, respectively. The situation is below 50% in district hospitals. The leakage of the roof and loose structures were observed in district hospitals and health center to be more than 50% of the incinerator houses. On other hand, the performance of burners and incinerator housing cleanliness are generally good. It was concluded that the incinerators in the HCFs are in bad conditions, necessitating maintenance.展开更多
The proper terminal disposal of organic solid waste such as domestic waste is a worldwide issue.Landfill covers a large area,with limited capacity,and a single landfill will be filled one day;incineration is costly to...The proper terminal disposal of organic solid waste such as domestic waste is a worldwide issue.Landfill covers a large area,with limited capacity,and a single landfill will be filled one day;incineration is costly to build and operate.These methods all need to transfer and centralized treatment,and secondary pollution is difficult to control,against the purification law of the nature."NIMBY effect"is very serious,and the social cost of treatment is increasing,becoming a heavy financial burden."The Distributed Waste Pyrolysis Cold Emission Energy Station"developed by Hunan Zhongzhou Energy-Saving Technology Co.,Ltd.overcomes these disadvantages and constructs a more appropriate environmental economic industrial chain for the treatment of organic solid waste such as urban and rural household waste.Based on its technical characteristics,this paper compares it with waste incineration power generation project in the aspects of secondary pollution control,treatment effect,energy utilization,investment and operation economy,etc.展开更多
Rapid development has led to a tremendous increase in the volume of solid waste produced in rural China.The annual amount of solid waste produced from Chinese rural areas is approximately 110 million tons.Many small-s...Rapid development has led to a tremendous increase in the volume of solid waste produced in rural China.The annual amount of solid waste produced from Chinese rural areas is approximately 110 million tons.Many small-scale solid waste incinerators have been built in Chinese rural areas.It was speculated that the emissions and potential risks of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs,commonly known as dioxins)and polychlorinated naphthalenes(PCNs)from these incinerators could be serious.A preliminary case investigation on PCDD/F and PCN emissions from a small-scale waste incinerator was performed.The stack gas samples were collected using auto isokinetic sampling techniques and PCDD/F and PCN congeners were identified and quantified by high resolution gas chromatography combined with high resolution mass spectrometry.Concentrations and toxic equivalents of PCDD/Fs emitted from the small-scale waste incinerator were 153 ngm^-3 and 5.6 ng TEQ m^-3,respectively,which was much higher than the regulatory level for municipal solid waste incinerators permitted in China and the European Union Directive.PCNs have similar toxicological effects with PCDD/Fs,and the relative potency factors(RPFs)of some PCN congeners(dioxin-like PCNs)to 2,3,7,8-tetrachlorinated dibenzo-p-dioxin(TCDD)were previously proposed to evaluate the dioxin-like toxicity of PCNs.The mass concentrations of PCNs and dioxin-like PCNs from the small-scale solid incinerator were 2927 ngm^-3 and 1137 ngm^-3,much higher than that of dioxins.However,much less attention has been paid to the small-scale incinerators compared with municipal solid waste incinerators.Here,we proposed that there should be a growing need to focus on the emissions and potential risks of dioxins and dioxin-like pollutants from these small-scale waste incinerators in rural China.展开更多
基金This work was supported by the Fundamental Research Funds for the Central Universities,CHD(grant number 300102212906)the Key R&D Plan of Shaanxi Province(grant number 2023-YBSF-390)+1 种基金the Innovation Capability Support Program of Shaanxi(grant number 2022TD-07)the Xianyang City,Shaanxi Province,China 2019 Key Research and Development Program(grant number 2019k02-125).
文摘Domestic waste incineration slag(WIS)includes fly ash and slag.Fly ash is classified as hazardous waste because it contains heavy metals.Most of slag are directly stacked or landfilled due to problems such as large output and low utilization rate.Harmless treatment is imminent.If WIS is used effectively in the road engineering,which can realize the high-quality and high-efficiency recycling of WIS,and it is of great significance to save resources and protect the environment.This study applies a geopolymer prepared from WIS fly ash as a stabilizing agent in WIS blending macadam for use as a pavement base mixture,and reports the mechanical properties(unconfined compressive strength,splitting strength,and resilience modulus)of the geopolymer-stabilized WIS blending macadam(GeoWIS).The leaching concentrations of harmful heavy metals of GeoWIS soaked in water were also investigated.Finally,the strength formation and heavy metal stability mechanisms were explored.The unconfined compressive strength,splitting strength,and compressive resilient modulus of GeoWIS all increased with increasing geopolymer content and decreasing WIS content.The strength of GeoWIS was derived from its geopolymerization and hydration products(C-S-H gel,N-A-S-H gel,and AFt).When the geopolymer content reached 12%–14%,the GeoWIS without natural macadam met the strength criterion of the asphalt pavement base.Through physical adsorption and chemical bonding,the geopolymer significantly reduced the leaching of harmful heavy metals.In GeoWIS with 50%WIS and stabilized with 10%geopolymer,the Cr,Ni,Cd,and Pb concentrations met the grade III groundwater standard.Concentrations of heavy metals leached from GeoWIS are low and exert little impact on environment.
文摘This paper provides analytical diagnosis of mechanical conditions of medical waste incinerators used for healthcare waste (HCW) treatment in Tanzania. The main features assessed were types of incinerators, features of incinerators and incinerator house. The assessment was conducted in three levels of health care facilities (HCFs), that is, Regional, district hospitals and health centers, existed in 26 regions of Tanzania. Questionnaires, interview and checklists were used as tools for data collection. It was observed that High-Tech incinerators are mainly used in regional hospitals, while district hospital and health center use both High-Tech and De-Montfort incinerators. About 60% of the incinerators have defective doors. More than 55% of incinerators are corroded in regional and district hospitals. The chimney, top plates and grate which are good condition are 55.6% and 60% in regional hospitals and health centers, respectively. The situation is below 50% in district hospitals. The leakage of the roof and loose structures were observed in district hospitals and health center to be more than 50% of the incinerator houses. On other hand, the performance of burners and incinerator housing cleanliness are generally good. It was concluded that the incinerators in the HCFs are in bad conditions, necessitating maintenance.
文摘The proper terminal disposal of organic solid waste such as domestic waste is a worldwide issue.Landfill covers a large area,with limited capacity,and a single landfill will be filled one day;incineration is costly to build and operate.These methods all need to transfer and centralized treatment,and secondary pollution is difficult to control,against the purification law of the nature."NIMBY effect"is very serious,and the social cost of treatment is increasing,becoming a heavy financial burden."The Distributed Waste Pyrolysis Cold Emission Energy Station"developed by Hunan Zhongzhou Energy-Saving Technology Co.,Ltd.overcomes these disadvantages and constructs a more appropriate environmental economic industrial chain for the treatment of organic solid waste such as urban and rural household waste.Based on its technical characteristics,this paper compares it with waste incineration power generation project in the aspects of secondary pollution control,treatment effect,energy utilization,investment and operation economy,etc.
基金We gratefully acknowledge support from the National 973 program(2015CB453100)the National Natural Science Foundation of China(21777172)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB14020102)Youth Innovation Promotion Association of the Chinese Academy of Sciences(2016038).
文摘Rapid development has led to a tremendous increase in the volume of solid waste produced in rural China.The annual amount of solid waste produced from Chinese rural areas is approximately 110 million tons.Many small-scale solid waste incinerators have been built in Chinese rural areas.It was speculated that the emissions and potential risks of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs,commonly known as dioxins)and polychlorinated naphthalenes(PCNs)from these incinerators could be serious.A preliminary case investigation on PCDD/F and PCN emissions from a small-scale waste incinerator was performed.The stack gas samples were collected using auto isokinetic sampling techniques and PCDD/F and PCN congeners were identified and quantified by high resolution gas chromatography combined with high resolution mass spectrometry.Concentrations and toxic equivalents of PCDD/Fs emitted from the small-scale waste incinerator were 153 ngm^-3 and 5.6 ng TEQ m^-3,respectively,which was much higher than the regulatory level for municipal solid waste incinerators permitted in China and the European Union Directive.PCNs have similar toxicological effects with PCDD/Fs,and the relative potency factors(RPFs)of some PCN congeners(dioxin-like PCNs)to 2,3,7,8-tetrachlorinated dibenzo-p-dioxin(TCDD)were previously proposed to evaluate the dioxin-like toxicity of PCNs.The mass concentrations of PCNs and dioxin-like PCNs from the small-scale solid incinerator were 2927 ngm^-3 and 1137 ngm^-3,much higher than that of dioxins.However,much less attention has been paid to the small-scale incinerators compared with municipal solid waste incinerators.Here,we proposed that there should be a growing need to focus on the emissions and potential risks of dioxins and dioxin-like pollutants from these small-scale waste incinerators in rural China.
