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.

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.