Generation rates of bottom and fly ash from thermal generation facilities in industrial and export processing zones in Ho Chi Minh City, Vietnam

The use of thermal generation facilities (TGFs) in manufacturing industries produces of a massive amount of bottom and fly ash (BFA) containing toxins, thus requiring proper management. In Ho Chi Minh city, more than 200 TGFs are in operation but the generation BFA and how it is handled is unknown, posing environmental and health risks if contaminants in BFA are leaching into the environment and accumulated in food webs. This study investigated the fuel demands of and the BFA generation from the TGFs in 17 industrial zones and export processing zones in Ho Chi Minh city to estimate BFA generation rates for various fuels. The results revealed a total consumption of 129,028 tons of diverse fuels per month, among which diesel oil (DO) and coal were of majority, accounting for 85,65% and 9,11% by weight, respectively. In addition to coal and DO, cashew husk, wood, and sawdust were among the most widely used fuels. BFA generation rates for rice husk, coal, sawdust, firewood, and cashew husk were 16.95 ± 28.12%, 10.62 ± 8.84%, 5.57 ± 7.34%, 4.88 ± 3.59% and 0.93 ± 1.37%, respectively. Automatically fuel feeding and small – medium TGFs showed higher BFA generation rates than manually fuel feeding and large ones. The findings help estimate the amount of BFA from MFs on larger scales, such as city, province, and country, which serves to develop an effective management strategy and plan.