Beijing plans to excavate waste buried in landfills, and to sort and incinerate it starting in 2015, in order to improve the sustainability of landfills, officials said at a conference held on Monday, Beijing News reported. The list of landfills involved in the waste incineration plan was not decided at the conference, held by the Beijing Commission of City Administration and Environment. At the conference, there was a discussion about some landfills that have been in service for more than 20 years, and how a check on the bottom layer is needed. The layers that are broken up are to be mended after the waste is excavated. Once burned, solid waste turns into ashes, taking up far less space, thus the stocked landfills can handle more waste in the coming years. The ammonia and nitrogen in the waste long buried have disintegrated into the land, so excavating the waste will not cause severe air pollution, said Liu Shenbo, chief engineer at a waste incineration power plant in Gaoantun village of Beijing.