✔ 最佳答案
Disadvantages of Recycling
The reprocessing of recovered materials is not always pollution free. Certain reprocessing technologies create residues which are difficult to treat. The acid-clay process for rerefining waste oil is one example where the residual sludge has contaminated land. Whether the use of recycled material is less polluting than virgin material can only be assessed on a project by project basis.
The effects of de-inking and repulping wastepaper are relatively benign, using currently available technology and modern inks which do not contain heavy metals, but de-inking does produce salt in effluent. The location of de-inking facilities and the policies adopted to manage salinity problems are therefore important in assessing the environmental effects of paper recycling.
The costs of collection, transport and reprocessing may be a disadvantage. This also results in higher costs for recycled materials.
The emphasis upon packaging means that a great deal of effort goes into extending the recycling of materials which account for only one tenth of total urban waste by weight. It also means that the focus is upon products such as PET bottles which are conspicuous in litter, even though they form a small part of the waste stream and do not have major adverse environmental effects. Some of these recycling schemes may bring no net gain to the community.
