苏州地区地下水资源城市应急利用适宜性研究

随着太湖水体富营养化程度的不断加剧,建立安全、稳定、可靠的应急备用水源日益重要。利用2005~2009年苏州地区地下水水质连续监测和补充监测资料,对第Ⅱ承压含水层进行了应急利用(生活饮用和工业利用)的水质适宜性和安全性评价分析。研究结果表明:第Ⅱ承含水层主要水化学类型为Na-HCO3、Ca-HCO3和Na-CaHCO3型,水质总体稳定,年际差异很小;地下水水质指数(WQI)均值较低(位于49.98~68.75之间),地下水没有受到有机物污染,可作为应急利用水源;WQI的水质指标贡献率表明,As、Fe、pH和Mn指标的贡献率最大,局部区域As、Fe、Mn及氨氮和亚硝酸盐含量较高,应急利用时应进行处理。朗格里尔饱和指数(LSI)和拉森比(LnR)评价结果表明,该水源易结垢,具有轻微腐蚀倾向,作为工业备用水源时应进行适当的处理。为苏州地区地下水应急水源建设和安全利用提供了科学依据和参考。

STUDY ON SUITABILITY OF GROUNDWATER RESOURCES FOR URBAN EMERGENCY USE IN SUZHOU CITY

As the water eutrophication situation becomes continuously serious in Taihu Lake, the construction of safe, stable, and reliable urban emergency water sourcehas been of greater importance. In this study, the suitability of urban emergency groundwater source for drinking and industrial purposes were assessed by using the water quality analysis results of the second confined groundwater from 2005 to 2009 in Suzhou city. Results showed that Na HCO3, Ca HCO3 and mixed Na Ca HCO3 type are the major hydrochemical types of the second cofined groundwater in the study area. The water quality is relatively stable and the inter annual difference is minimal during the study period. Physico chemical characterizations and water quality index (WQI) of the samples revealed that groundwater from most of sites were acceptable for drinking purpose owing to low mean yearly WQI values (4998-6875), and the confined groundwater is not polluted by any organic compounds. Thus, groundwater from the study area is suitable for drinking purpose. Results of contribution rate of water indexes for WQI value revealled that As, Fe, pH and Mn are the main impact indexes. The concentration of iron, manganese, arsenic, ammonia and nitrite are generally high in some areas, and these redundant ions should be pre treated before emergency useage. Langeliar saturation index (LSI) and Larsen ratio (LnR) results showed that all water samples are scale forming tendencies in nature with a slight tendency to corrosion characteristics for most of the samples. To meet the water quality requirement for drinking and industrial purposes during emergency water supply period, additional water pre treatment technologies should be recommended. This study provides a scientific basis and reference for the construction of regional groundwater emergency water source and the indemnification of water quality security during emergency water supply periods for Suzhou city