Water Quality Characteristic And Removes Of Fe And Mn In Groundwater Resource Fields Near The River

The groundwater plays an important role in urban drinking water supply for its relatively stable quality and quantity. However, the pollution caused by iron and manganese has becoming a large problem for the groundwater treatment in recent years.. The present research first investigated the groundwater quality of the northwest of Xi'an city systematically. Secind, to provide foundation for upgrading of groundwater supplying plant, a series of pilot-csale experiments were conducted to mainly remove iron and manganese based on the investigation results that that iron, manganese commonly exceeded the safe limits, ammonia, while over standard of turbidity and visible object were occasionally observed..The investigation results showed that Mn frequently exceeded the standard limits,and the number of tubes contaminated by Mn could account for 71.8% of total tubes. Meanwhile 34.4% of total tubes were founded that visible objects exceeded the standard. In addition, Fe was observed exceeding the standard in 25% of total tubes. Based on the comparison of present investigation results to monitoring data of water quality in recent years, it is obvios that the content of Mn, Fe, ammonia and turbidity are increasing these years. Addition, Wei River was proved to be the main pollution source, while Taiping River had little effect on the groundwater quality."potassium permanganate oxidation+sand filter", which mainly removing iron and manganese, was selected as the treatment process used in pilot-scale test.based on the results of optimal process. The pilot-scale results showed that Fe was not detected at filter velocity of 8.12 m h-1,9.74 m h-1 and 12 m h-1, provided 90% of theoretical value of KMnO4 was added as pre-oxidant. Meanwhile, Mn content was lower than 0.1 mg L-1 and turbidity was stable at 0.25 NTU. Under the above conditions, chroma was less than 15 degree and about 34% ammonia were removed. In present test, Mn content of effluent decreased with the increase of filter rate and the the remove efficency of Mn occurred at the filter velocity of 12 m h-1. In addition, The highest water production efficiency was observed at 9.74 m h-1.The present results proved that the process of "potassium permanganate oxidation+ sand filter" was an effective method for the removing of Fe and Mn from groundwater, which it provids foundation for the upgrading of groundwater plant.