According to Yangcheng Evening News, Guangzhou is approaching a more environment-friendly method for disposing of contaminated milk--burning it in a high temperature furnace and using the residue for brick-making.
Wang said that the previous disposal method--landfill--has its drawbacks. The volume of milk that can be dealt with is limited. In order to accelerate disposal, they have discovered a more environment-friendly method--using the milk to manufacture bricks and cement.
It transpires that the best method to destroy the contaminated milk is incineration by pyrolysis, but after the removal of the packed liquid, a fine-particle filtration is required before combustion, which requires advanced technology and carries a high cost. After discussions with various experts, officials reached the conclusion that using the high temperature furnace of a brick kiln or cement plant would achieve the same result with little pollution, and that after evaporation of the water content and burn-off the residue can be made into bricks and cement.
It seems that this method will cost about 700 yuan per ton, which is cheaper and more environment-friendly. Officials will also look to negotiate with relevant businesses for a price reduction. The cost of the first method adopted--solid waste processing--is the highest at 2,500 yuan per ton, while landfill solution is cheaper, at about 150-200 yuan per ton, but is limited in the volumes it can deal with and requires daily control over discharges.
Wang said that technical issues remain to be verified if the "milk" is to be used to make bricks and cement, such as whether lower temperatures would be a problem or if it would affect the quality of the finished product if water-bearing materials are introduced into a high temperature furnace. Theoretically these issues should not create any problem, but validation experiments are required, to which some large cement plants in Guangzhou have been linked.
(China.org.cn by Jessica Zhang, November 12, 2008)