Using a proven thermal technology known as “fluidized bed” incineration, the STF treats sewage sludge through ultra-high temperature combustion. This advanced technique suspends the sludge in a hot bubbling bed of sand, through which jets of air are blown to mix the sludge with sand rapidly and to provide the oxygen necessary for combustion. The thermal gases in the incinerator reach a temperature above 850°C for at least 2 seconds in order to control emissions of organic pollutants. To further reduce certain pollutants in the flue gases, lime is injected to capture acidic pollutants whereas ammonia is added to reduce nitrogen oxide emissions. The remaining sludge, in the forms of ash and residues which is about 10 percent of the original volume, is transported by covered trucks to the adjacent West New Territories Landfill for disposal. In other words, the treatment process is able to reduce the volume of waste up to 90 percent.
