Abstract:

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