09:26 | 29/06/2015 Science - Technology
(VEN) - Holcim Vietnam’s expert Pham Tran Gia Bang claims that hazardous solid waste will be used as burning material in cement kilns at high temperatures to produce cement products.
According to the Ministry of Natural Resources and Environment, domestic economic sectors dispose of more than 113,000 tonnes of hazardous solid waste annually, including persistent organic pollutants (POPs). The Holcim Vietnam Co., Ltd. is the only unit licensed to burn this waste in cement kilns, offering an ideal waste treatment solution.
A common cement kiln has burning capacity of two tonnes of hazardous solid waste per hour at 1,450 degree Celsius. Cement kilns will be fed with the waste via material feeding points while cement quality and gas emissions will be monitored via a monitoring system.
Thanks to high temperatures and long durations, persistent organic waste will be totally burned in cement kilns. For example, polychlorinated biphenyl (PCB) containing oil of acceptable concentration will be fed into cement kilns at 2,000 degree Celsius feeding points to ensure that it won’t generate Furan or Dioxin. The oil will be burned into steam and CO2 and HCL emissions. HCL emission will be absorbed by the alkaline environment in the kiln, destroying the PCBs in situ.
With this technology, the Holcim Vietnam Co., Ltd. piloted the burning of two tonnes of oil containing PCBs sent by the Saigon Water Supply Corporation’s Thu Duc Water Plant, at its cement kilns in Hon Chong, Kien Giang Province, in 2011, 25 tonnes of earth contaminated with POPs in Thai Nguyen in 2012, nearly seven tonnes of PCB-contaminated transformer oil discharged by the Cuu Long Trading Investment JSC in 2014, and nearly 700 tonnes of earth contaminated with POPs so far this year.
These tests were witnessed by representatives of the Ministry of Natural Resources and Environment, departments of natural resources and environment, local authorities, consultancy panel and international experts. They proved to be able to destroy PCB by 99.99 percent while reaching the QCVN 41:2011/BTNMT standard for emissions issued from burning hazardous solid wastes in cement kilns. The emission processes were monitored and tested by SGS, a world leading inspection, verification, testing and certification company.
This approach is regarded as a sustainable solution to address waste problems in replacement of traditional solutions including dumping. However, the costs of hazardous solid waste transportation and burning expenses will be an inevitable cost for firms but a price well worth paying if the environment is to be protected.