Problems at Green Island trials

Problems at Green Island trials
Published: 03 May 2005

A new incineration plant designed to turn solid waste into ash for the manufacture of cement encountered technical problems during a trial run late last month, one of Hong Kong’s biggest cement makers admitted Tuesday.

Green Island Cement was responding to Monday’s report in The HK Standard which revealed that harmful gases were released after problems occurred during the incinerator’s test run from April 21-25. Green Island’s general manager Choi Ka-keung admitted there were some problems during the test, saying the incinerator’s system alarm went off on two occasions. The failure was the result of a motor burn-out, Choi said.

The water pump is used to push air into the combustion chamber of the incinerator. A source close to the plant in Tuen Mun told The Standard Sunday that harmful gases were released after low levels of oxygen were recorded in the combustion chamber, suggesting that waste material was not being burned efficiently. For incineration to take place without causing significant air pollution, oxygen levels during the process should be 8 percent under a license requirement set by the Environment Protection Department’s Air Pollution Control Ordinance. However, during the April 25 tests, the oxygen level was 4.53 percent and 5.76 percent respectively.

 Choi called the 8 percent figure a guideline and said the readings were not a serious problem. The incineration technology in use was developed by the University of Science and Technology with HK$9 million in government funds and a matching amount from Green Island. It is intended to help relieve the use of landfill from the disposal of municipal solid waste.

The problems, according to the source, could be the result of a substandard manufacturing process. The equipment for the plant was made in the mainland and this may be the reason for the problems, said the source. Hong Kong University of Science and Technology professor Gordon McKay, who is in charge of the incineration research project, said the main components were supplied by a mainland company called Chico China a construction firm. Green Island Cement Holdings executive director Don Johnston told The Standard  that although there were some problems it is too early to draw any conclusions.