CONTROLLING THE NON-POINT POLLUTION IN BAIYANGDIAN LAKE BY MEANS OF ECOLOGICAL ENGINEERING TECHNIQUES

摘要

Baiyangdian Lake, the largest freshwater lake in North China, is known as "Pearl of North China" and "kidney of North China" for its abundant products and multiple ecological services. However, from the 1970s, due to the ever-increasing discharge of polluted water from upstream rivers, it has been severely polluted. In 1996, with the establishment and operation of two sewage treatment plants in the city of Baoding, the water quality in the Baiyangdian Lake was improved significantly. Despite the efforts made by relevant departments these years, the water quality is still not favorable nowadays. According to the monitoring results in 2003, the water quality in most areas of the lake was inferior to category V national water quality standard and the major pollutions are TP (total phosphorus), TN (total nitrogen) and NH_3-N (ammonia nitrogen). Non-point pollution was identified as the major cause of the pollution in the Baiyangdian Lake through investigation on the spot. Apart from strengthening control of major industrial pollution sources, improving the purification ability of non-point pollutants in the regional environment should be the main approach to control the pollution in this region. On the basis of analysis, investigation and simulative experiments, the control of sources and runoff techniques and measures pollution involving ecological fertilization, conservation of soil and water, sewage and solid waste treatment and establishment of ecological buffer zones and wetland ecological systems were put forward to control the pollution in the Baiyangdian Lake.