关键词: 铅离子, 好氧颗粒污泥, 理化性质, 去除率

Abstract: The authors used remote sensing data (NOAA-AVHRR) and took the Normalized Difference Vegetation Index (NDVI) as an indicator of vegetation growth to explore the trends of grassland growth and their dynamic responses to climate change from 1982 to 2010. Overall, during the 29 years, the national averaging growing season NDVI significantly increased (R²=0.25, p<0.01), especially during the period 1982?1999 (R²=0.25, p<0.01). This trend, however, was stalled since the late 1990s. Furthermore, as for the trend over the period 1999?2010, its magnitude or even the sign of change substantially depended on the choice of the beginning year. This suggests a non-significant trend in China’s grassland growth over this period. The trends of growing season NDVI also showed remarkably spatial-temporal differences. The extensive grassland greening trend that occurred during the earlier study period 1982?1999 appeared a wide-range reversal during the following study period 1999?2010, especially in the arid and semi-arid regions. The condition of hydro-thermal combination was the main factor controlling these growth changes. Correlation analysis between growing season NDVI and climate factors showed that in most parts of grasslands in China, the vegetation growth was rather driven by precipitation than by temperature. While for the grasslands in alpine regions and humid or semi-humid regions, the growing season NDVI correlated closely to temperature, indicating that warming exerted a positive effect on grassland growth in these areas.

Key words: lead ion, aerobic granular sludge, physicochemical properties, removal efficiency