Recycled powder(RP)is produced as a by-product during the process of recycling construction and demolition(C&D)wastes,presenting a low additional value.Using RP-based solidifying material can not only improve its ...Recycled powder(RP)is produced as a by-product during the process of recycling construction and demolition(C&D)wastes,presenting a low additional value.Using RP-based solidifying material can not only improve its utilization efficiency,but also reduce the cost of commercial solidifying materials.To date,this is the best solidifying material utilized to dispose the original waterworks sludge(OWS)with high moisture contents(60%),and the product could be used to fabricate non-fired bricks.This has become a new environment-friendly technology of“using waste to treat waste”.In this paper,the influence of different particle sizes and dosages of RP on the prepared solidifying material was studied.Besides,unconfined compression strength(UCS),volume stability,chemical composition,and heat of hydration,pore structure of the solidifying material were characterized.Then,non-fired bricks were prepared by using the solidifying material,recycled aggregate,and original waterworks sludge.The UCS and softing coefficient(SC)of the non-fired bricks were evaluated.As a result,the 28-day UCS of the solidifying material with optimal(M30)was 35.40 MPa,which could reach 84.37%of Portland cement(PC).The addition of RP increased the volume stability of the solidifying material.The addition of a large amount of RP reduced the heat flux and cumulative heat release of the solidifying material,while its porosity increased.The UCS of non-fired brick(NF20)in 28 days was 15.19 MPa and the SC after 28 days was 78.35%.In conclusion,the preparation of solidifying material using RP could be a promising approach and has a great potential in disposal of original waterworks sludge.展开更多
The aim of this research is to find substitute barrier materials for natural clay from two kinds of municipal sludge: waterworks sludge(S_w) and dredging sludge(S_d). Laboratory tests were performed firstly to determi...The aim of this research is to find substitute barrier materials for natural clay from two kinds of municipal sludge: waterworks sludge(S_w) and dredging sludge(S_d). Laboratory tests were performed firstly to determine their Atterberg limits and hydraulic conductivity. Based on the results, the use of waterworks sludge was recommended. Then, shear strength tests were performed and it was found the shear resistance property of waterworks sludge is strong enough to maintain slope stability. In order to evaluate the possibility of secondary pollution, the heavy metal contents of waterworks sludge was determined and the results indicated that secondary pollution is unlikely happened. Finally, economic analysis proves that reusing waterworks sludge as barrier will reduce the lost a great for both landfill and waterworks. Based on the results, waterworks sludge was proposed to use and a further long-term simulated landfill test was suggested.展开更多
Objective Since haloacetic acids (HAAs), which are nonvolatile and of high carcinogenic risk, are common species of chlorinated disinfection by-products(DBPs) in drinking water, and little has been known in China, it...Objective Since haloacetic acids (HAAs), which are nonvolatile and of high carcinogenic risk, are common species of chlorinated disinfection by-products(DBPs) in drinking water, and little has been known in China, it is necessary to make a survey about the kinds and levels of HAAs in drinking water of the nation. Method HAAs were analyzed using gas chromatography with electron capture detector(GC/ECD) and relatively complex pretreatment process of sample was applied. Five main cities in different areas of China were chosen in the survey. Results Studies showed that the main species of HAAs in drinking water in China were DCAA and TCAA, ranging from 0.4 礸/L to 12.85 礸/L and from 0.56 礸/L to 10.98 礸/L, respectively. MBAA and DBAA were also detected in one city, ranging from 2.20 礸/L to 4.95 礸/L and 1.10 礸/L to 2.81 礸/L, respectively. Therefore, the contents of HAAs varied, usually no more than 25 礸/L. Based on the acquired data to date, it is known that the concentrations of HAAs in drinking water in China were surely under the limits of Sanitary Standard for Drinking Water Quality (China, 2001). Conclusion A wider survey of HAAs in drinking water should be conducted throughout the nation to get adequate data and information, the ultimate aim of which is to control HAAs pollution and keep the balance between microbiological safety insurance and chemical risk control, minimize the formation of DBPs and ensure the safety of water supply at the same time.展开更多
Given the cultural and environmental potential presented by historical water infrastructures in urban contexts,this article states the evidence of a not much documented urban phenomenon in Portugal,the refurbishment o...Given the cultural and environmental potential presented by historical water infrastructures in urban contexts,this article states the evidence of a not much documented urban phenomenon in Portugal,the refurbishment of water heritage protected areas motivated by European-based regeneration projects.By employing a case-study design,four good practices-placed inÉvora,Lisbon,Braga and Guimarães-are chosen to enlighten this growing and aware trend.The assets located there-theÁgua de Prata Aqueduct,theÁguas Livres Aqueduct,the Sete Fontes water-supply system and the Zona de Couros industrial area,respectively-are geographical,historical and culturally characterised,while the projects that concern them are documented by visiting the areas and analysing the available sources.Then,open-data platforms and heritage protection decrees are processed to graphically code the topography,hydrology,urban land use,infrastructures,landmarks and protected areas,employing QGIS free software for Geographic Information Systems.As a result,the four practices are documented,discussed and compared.A table assesses and summarises their pre-existing and currently added values and a series of diagrams illustrates the landscape changes generated.These graphics validate the practices and update the status of the assets,enhancing the rediscovery of the existing landscapes and showing the main challenges and future opportunities faced by these areas.展开更多
基金This work was supported by the Jiangsu Provincial Science and Technology Department’s Social Development-Major Science and Technology Demonstration Project(Grant No.BE2018697)the Demonstration Engineering Technology Research Center of Suqian Science and Technology Bureau(Grant No.M201912)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Recycled powder(RP)is produced as a by-product during the process of recycling construction and demolition(C&D)wastes,presenting a low additional value.Using RP-based solidifying material can not only improve its utilization efficiency,but also reduce the cost of commercial solidifying materials.To date,this is the best solidifying material utilized to dispose the original waterworks sludge(OWS)with high moisture contents(60%),and the product could be used to fabricate non-fired bricks.This has become a new environment-friendly technology of“using waste to treat waste”.In this paper,the influence of different particle sizes and dosages of RP on the prepared solidifying material was studied.Besides,unconfined compression strength(UCS),volume stability,chemical composition,and heat of hydration,pore structure of the solidifying material were characterized.Then,non-fired bricks were prepared by using the solidifying material,recycled aggregate,and original waterworks sludge.The UCS and softing coefficient(SC)of the non-fired bricks were evaluated.As a result,the 28-day UCS of the solidifying material with optimal(M30)was 35.40 MPa,which could reach 84.37%of Portland cement(PC).The addition of RP increased the volume stability of the solidifying material.The addition of a large amount of RP reduced the heat flux and cumulative heat release of the solidifying material,while its porosity increased.The UCS of non-fired brick(NF20)in 28 days was 15.19 MPa and the SC after 28 days was 78.35%.In conclusion,the preparation of solidifying material using RP could be a promising approach and has a great potential in disposal of original waterworks sludge.
文摘The aim of this research is to find substitute barrier materials for natural clay from two kinds of municipal sludge: waterworks sludge(S_w) and dredging sludge(S_d). Laboratory tests were performed firstly to determine their Atterberg limits and hydraulic conductivity. Based on the results, the use of waterworks sludge was recommended. Then, shear strength tests were performed and it was found the shear resistance property of waterworks sludge is strong enough to maintain slope stability. In order to evaluate the possibility of secondary pollution, the heavy metal contents of waterworks sludge was determined and the results indicated that secondary pollution is unlikely happened. Finally, economic analysis proves that reusing waterworks sludge as barrier will reduce the lost a great for both landfill and waterworks. Based on the results, waterworks sludge was proposed to use and a further long-term simulated landfill test was suggested.
文摘Objective Since haloacetic acids (HAAs), which are nonvolatile and of high carcinogenic risk, are common species of chlorinated disinfection by-products(DBPs) in drinking water, and little has been known in China, it is necessary to make a survey about the kinds and levels of HAAs in drinking water of the nation. Method HAAs were analyzed using gas chromatography with electron capture detector(GC/ECD) and relatively complex pretreatment process of sample was applied. Five main cities in different areas of China were chosen in the survey. Results Studies showed that the main species of HAAs in drinking water in China were DCAA and TCAA, ranging from 0.4 礸/L to 12.85 礸/L and from 0.56 礸/L to 10.98 礸/L, respectively. MBAA and DBAA were also detected in one city, ranging from 2.20 礸/L to 4.95 礸/L and 1.10 礸/L to 2.81 礸/L, respectively. Therefore, the contents of HAAs varied, usually no more than 25 礸/L. Based on the acquired data to date, it is known that the concentrations of HAAs in drinking water in China were surely under the limits of Sanitary Standard for Drinking Water Quality (China, 2001). Conclusion A wider survey of HAAs in drinking water should be conducted throughout the nation to get adequate data and information, the ultimate aim of which is to control HAAs pollution and keep the balance between microbiological safety insurance and chemical risk control, minimize the formation of DBPs and ensure the safety of water supply at the same time.
基金This work was supported by the[VI Plan Propio de Investigaciòn y Transferencia of the University of Seville]under Grant[VIPPIT-2017-II.2 and VIPPIT-2020-EBRV][Instituto Universitario de Arquitectura y Ciencias de la Construcciòn]under Grant[VIII Ayudas a la Internacionalizaciòn de la Investigaciòn-2020].
文摘Given the cultural and environmental potential presented by historical water infrastructures in urban contexts,this article states the evidence of a not much documented urban phenomenon in Portugal,the refurbishment of water heritage protected areas motivated by European-based regeneration projects.By employing a case-study design,four good practices-placed inÉvora,Lisbon,Braga and Guimarães-are chosen to enlighten this growing and aware trend.The assets located there-theÁgua de Prata Aqueduct,theÁguas Livres Aqueduct,the Sete Fontes water-supply system and the Zona de Couros industrial area,respectively-are geographical,historical and culturally characterised,while the projects that concern them are documented by visiting the areas and analysing the available sources.Then,open-data platforms and heritage protection decrees are processed to graphically code the topography,hydrology,urban land use,infrastructures,landmarks and protected areas,employing QGIS free software for Geographic Information Systems.As a result,the four practices are documented,discussed and compared.A table assesses and summarises their pre-existing and currently added values and a series of diagrams illustrates the landscape changes generated.These graphics validate the practices and update the status of the assets,enhancing the rediscovery of the existing landscapes and showing the main challenges and future opportunities faced by these areas.
