1.前言我国水资源不足,全国有70%的城市缺水,而水资源被污染也极其严重,据前二年统计,全国污水排放量240亿吨/年,其中80%以上未经任何处理直接排入水域,使可利用水资源愈来愈少,许多国家废水利用率高达50—60%,我国的一些大企业里废水利用率仅20—30%,许多企业根本不回收利用废水,全国废水利用率约2.5%。有些废水仅须去除悬浮物即可重复使用,因此以无烟煤滤料为主的双层或三层滤池高效,价廉的处 1. Foreword China’s water resources are insufficient, 70% of the cities in the country are short of water, and the water resources are polluted is extremely serious. According to the statistics of the previous two years, the national sewage discharge is 24 billion tons/year, of which more than 80% is without any treatment. Directly discharged into the waters, the available water resources are becoming less and less. In many countries, the utilization rate of wastewater is as high as 50-60%. In some large enterprises in China, the utilization rate of wastewater is only 20-30%, and many companies do not recycle wastewater. The utilization rate of wastewater is about 2.5%. Some wastewater can be reused only by removing suspended solids, so double- or triple-filters based on anthracite filter media are highly efficient and inexpensive.