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Nguyen LH, Tran TVN, Hoang MG, Nguyen HG, Tong TK, Isobe Y, Kawasaki M, Ishigaki T, Kawamoto K. Material and monetary flows of construction and demolition waste and assessment on physical and environmental properties of illegally dumped construction and demolition waste in Hanoi. Environ Sci Pollut Res Int 2023; 30:125965-125976. [PMID: 38008831 DOI: 10.1007/s11356-023-30978-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 11/05/2023] [Indexed: 11/28/2023]
Abstract
The main aim of this study is to investigate the material and monetary flows of CDW management and to characterize the distribution of illegally dumped CDW in Hanoi. Construction and demolition waste management has become a source of much concern to the urban authorities and citizens of big cities in Vietnam. It is estimated that 3000 t of CDW were generated per day from construction and demolition activities in Hanoi, but only 45% of the CDW was received at official landfills, while 55% of the CDW was disposed of elsewhere. The consequences of improper waste management are potentially alarming. The study conducted interviews to identify the material and cash flow associated with licensed and unlicensed contractors in CDW classification, transportation, treatment, and disposal, to characterize the distribution of illegally dumped CDW in two districts in Hanoi (urban and suburban districts), and to assess the composition of dumped CDW and environmental assessment of illegally dumped CDW by chemical analyses such as leaching and content tests. The study concluded that illegal dumping was performed mostly by unlicensed private companies. The illegally dumped CDW was mostly composed of mixed materials such as concrete, bricks, stones, and some hazardous materials such as asbestos and gypsum were found. The environmental concern of illegally dumped CDW was mostly dust, blockage of water ways, and inundation of increased suspended solids, whereas the heavy metal leaching concentration of all samples was below the environmental standards in Vietnam.
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Affiliation(s)
- Lan Huong Nguyen
- Department of Environmental Engineering, Hanoi University of Civil Engineering, No. 55, Giai Phong Street, Hai Ba Trung District, Hanoi, 10000, Vietnam
| | - Thi Viet Nga Tran
- Department of Environmental Engineering, Hanoi University of Civil Engineering, No. 55, Giai Phong Street, Hai Ba Trung District, Hanoi, 10000, Vietnam.
| | - Minh Giang Hoang
- Department of Environmental Engineering, Hanoi University of Civil Engineering, No. 55, Giai Phong Street, Hai Ba Trung District, Hanoi, 10000, Vietnam
| | - Hoang Giang Nguyen
- Department of Environmental Engineering, Hanoi University of Civil Engineering, No. 55, Giai Phong Street, Hai Ba Trung District, Hanoi, 10000, Vietnam
| | - Ton Kien Tong
- Department of Environmental Engineering, Hanoi University of Civil Engineering, No. 55, Giai Phong Street, Hai Ba Trung District, Hanoi, 10000, Vietnam
| | - Yugo Isobe
- Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama, 3470115, Japan
| | - Mikio Kawasaki
- Center for Environmental Science in Saitama, 914 Kamitanadare, Kazo, Saitama, 3470115, Japan
| | - Tomonori Ishigaki
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 3058506, Japan
| | - Ken Kawamoto
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Saitama, 3388570, Japan
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Duong TH, van Eekert M, Grolle K, Tran TVN, Zeeman G, Temmink H. Effect of carbohydrates on protein hydrolysis in anaerobic digestion. Water Sci Technol 2022; 86:66-79. [PMID: 35838283 DOI: 10.2166/wst.2022.200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This study aimed to assess the effect of carbohydrates on protein hydrolysis and potential implications for the design of anaerobic reactors for treatment of protein-rich wastewaters. Batch experiments were carried out with dissolved starch (Sta) and gelatine (Gel) at different chemical oxygen demand (COD) ratios ranging from 0 to 5.5 under methanogenic conditions for methane production and up to 3.8 under non-methanogenic conditions for volatile fatty acids (VFA), both at 35 °C. The Sta/Gel did not have a direct effect on the gelatine hydrolysis rate constants under methanogenic (0.51 ± 0.05 L g VSS-1 day-1) and non-methanogenic conditions (0.48 ± 0.05 L g VSS-1 day-1). However, under non-methanogenic conditions, gelatine hydrolysis was inhibited by 64% when a spectrum of VFA was added at a VFA/Gel (COD) ratio of 5.9. This was not caused by the ionic strength exerted by VFA but by the VFA itself. These results imply that methanogenesis dictates the reactor design for methane production but hydrolysis does for VFA production from wastewater proteins.
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Affiliation(s)
- Thu Hang Duong
- Environmental Technology, Wageningen University and Research, 6708 WG Wageningen, The Netherlands E-mail: ; ; Faculty of Environmental Engineering, Hanoi University of Civil Engineering, 55 Giai Phong Road, Hai Ba Trung, Hanoi, Vietnam
| | - Miriam van Eekert
- Environmental Technology, Wageningen University and Research, 6708 WG Wageningen, The Netherlands E-mail: ;
| | - Katja Grolle
- Environmental Technology, Wageningen University and Research, 6708 WG Wageningen, The Netherlands E-mail: ;
| | - Thi Viet Nga Tran
- Faculty of Environmental Engineering, Hanoi University of Civil Engineering, 55 Giai Phong Road, Hai Ba Trung, Hanoi, Vietnam
| | - Grietje Zeeman
- Environmental Technology, Wageningen University and Research, 6708 WG Wageningen, The Netherlands E-mail: ; ; LeAF BV, PO Box 500, 6700 AM Wageningen, The Netherlands
| | - Hardy Temmink
- Environmental Technology, Wageningen University and Research, 6708 WG Wageningen, The Netherlands E-mail: ;
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Nguyen LH, Nguyen TD, Tran TVN, Nguyen DL, Tran HS, Nguyen TL, Nguyen TH, Nguyen HG, Nguyen TP, Nguyen NT, Isawa T, Ta Y, Sato R. Steel slag quality control for road construction aggregates and its environmental impact: case study of Vietnamese steel industry-leaching of heavy metals from steel-making slag. Environ Sci Pollut Res Int 2022; 29:41983-41991. [PMID: 34564812 DOI: 10.1007/s11356-021-16438-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 09/05/2021] [Indexed: 06/13/2023]
Abstract
Steel slag is an industrial by product of steel manufacturing processes and has been widely utilized within civil and construction materials for road materials and environmental remediation in countries like Japan, USA, and European Union nations. However, the current utilization of steel slag in Vietnam is very low mainly because of lack of quality control of slag treatment and chances for reuse of treated steel slag. This paper presents the up to date steel slag production status in Vietnam through the extensive survey and sampling at seven large steel factories. The paper also highlights the environmental and quality control issues of these steel slags to use as road construction aggregates by assessing the heavy metals concentration in the leachate. The basic oxygen furnace (BOF) and electric arc furnace (EAF) slag samples were collected to evaluate leaching properties of metals leached from the slags. The two standardized batch leaching tests of steel slag roadbed material in Japan (JIS K 0058-1) and toxicity characteristics leaching procedure (TCLP-EPA method 1311) were performed to the evaluated the hazardous metals. The results of the leaching test show that almost all of the concentration of the metals in the leached solution does not exceed the National Standard for Industrial Wastewater Discharge (QCVN 40-2011). The pH and parameters such as total chromium, nickel, copper, lead, arsenic, and manganese differ from the two test methods. The acidic conditions employed in the EPA 1311 were not representative of condition excepted during slag reuse in road constructions because in the operation condition of the road, acidic liquid is absent. The leaching test results confirmed that JIS test which uses deionized water with gentle mixing prevents the slag sample from size degradation is suitable for the environmental assessment of steel slag use for roadbed material. This research suggests that the adjustment of pH value prior to disposal or reuse as base materials and official guideline should be promulgate by the authorities to ensure the leachate meet the surface water quality standard.
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Affiliation(s)
- Lan Huong Nguyen
- Faculty of Environmental Engineering, Hanoi University of Civil Engineering, Hanoi, Vietnam
| | - Tien Dung Nguyen
- Faculty of Building Materials, Hanoi University of Civil Engineering, Hanoi, Vietnam
| | - Thi Viet Nga Tran
- Faculty of Environmental Engineering, Hanoi University of Civil Engineering, Hanoi, Vietnam
| | - Duc Luong Nguyen
- Faculty of Environmental Engineering, Hanoi University of Civil Engineering, Hanoi, Vietnam
| | - Hoai Son Tran
- Faculty of Environmental Engineering, Hanoi University of Civil Engineering, Hanoi, Vietnam
| | - Thuy Lien Nguyen
- Faculty of Environmental Engineering, Hanoi University of Civil Engineering, Hanoi, Vietnam
| | - Thi Huong Nguyen
- Vietnam Japan Institute for Advanced Technology, Hanoi University of Civil Engineering, Hanoi, Vietnam
| | - Hoang Giang Nguyen
- Faculty of Building and Industrial Construction, Hanoi University of Civil Engineering, Hanoi, Vietnam.
| | - Tan Phong Nguyen
- Faculty of Environment, Natural Resources and Climate Change, Ho Chi Minh City University of Food Industry, Ho Chi Minh City, Vietnam
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Khatlwada NR, Takizawa S, Tran TVN, Inoue M. Groundwater contamination assessment for sustainable water supply in Kathmandu Valley, Nepal. Water Sci Technol 2002; 46:147-154. [PMID: 12448463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A study was carried out to assess the water quality situation of groundwater sources in Kathmandu Valley, Nepal. Groundwater has remained to be a major water supply source for a population of 1.5 million at present in the valley. The focus of this study was to evaluate the extent and sources of groundwater contamination. Water sampling was carried out in selected deep wells and shallow sources. The level of pollution was evaluated by comparing the water quality results with WHO guidelines. The major problems with the dug wells, hand pumps and spouts were found to be the elevated nitrate and mercury contents. The deep wells located on the central aquifer were found to have a serious threat of ammonia pollution. Deep wells were also found to have iron, manganese and mercury concentrations exceeding the guideline values. Multivariate statistical analysis was carried out to cluster the sampling sources and identify the common factors describing the potential sources and possible mechanisms associated with the contaminants. The results suggested that disintegration of the sediment organic matter under strong reducing environment leads to the origin of the unusual water qualities at the central confined aquifer. This process may be microbially mediated and occurs with the simultaneous reduction of species such as arsenic, iron, manganese and sulfate. Both natural and anthropogenic water quality problems were observed in the groundwater system of Kathmandu valley. Attention should be focused to consider distinct strategies to address these problems.
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Affiliation(s)
- N R Khatlwada
- Department of Urban Engineering, The University of Tokyo, Japan
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