Treatment of high hardness and strontium-rich groundwater by chemical softening-ultrafiltration process
高硬度富锶地下水的软化沉淀-超滤膜联用工艺

Chemical softening-ultrafiltration processes with lime or lime-sodium carbonate composite as the softening agents were investigated on the treatment of high hardness and strontium-rich groundwater,and the effects of chemical dosage on the strontium content in the effluents were studied.The results showed that the total hardness was reduced from 287.12 mg/L to 96.44 mg/L with its removal of 66.41% and strontium content in the effluent was from 0.37 mg/L to 0.21 mg/L at the optimal dosage of 270 mg/L Ca(OH)2,while for the lime-sodium carbonate method the total hardness was 60.34 mg/L with 78.98% of the removal and strontium content was 0.02 mg/L at the optimal dosage of 270 mg/L Ca(OH)2 and 160 mg/L Na2CO3.Both the lime and lime-sodium carbonate composite methods by the chemical softening/ultrafiltration process can get the effluent total hardness to the requirement for groundwater softening treatment.The effluents by the lime softening/ultrafiltration method still maintain its high-level content of trace strontium,which is beneficial to man's health and makes them suitable for the quality of strontium-rich mineral water,whereas a great loss of trace strontium in the groundwater was resulted in by the lime-sodium carbonate composite softening/ultrafiltration method.