Research On Risk-Reducing Technology Of Accidental Pollution In The Water Plant

In recent years, the break frequency of the water sources’ pollution accidentstends to inerease in China. However，most of Chinese waterworks doesn’t have theability to handle the sudden pollution, which can threaten the safety of drinking water.For almost of these waterworks using the conventional treatment process, which aredesigned under the condition that the water quality meet the standards, so theirtreatment and response ability to sudden water pollution is weak. This paper relies onthe "State11th Five-Year-Plan Water Project"-"Pearl River downstream drinkingwater security technology integration and comprehensive demonstration.", whichcombined with the status of Pearl River’s raw water and the treatment features of thewater plant A, to study emergency control measures for the plant if the raw watersuddenly change.By analyzing the conventional water quality, we choose turbidity and algae asthe endogenous mutation pollutants. For the sudden mutation pollutants, we select theodor substances （DMS and DMDS） and hexavalent chromium （Cr VI） as the studyobject. Typical pollutants emergency disposal methods were incorporated in thesoftware to form a complete software system for water plant’s emergency control.The warning level of turbidity for waterworks is280NTU and emergencymethod is dosing PAC for coagulation and sedimentation, the removal rate can reachmore than99%. NaClO is selected to remove algae; the algae removal rate can reachabout82%, when NaClO dosing1.6mg/L. Early warning value for Cr （VI） is0.062mg/L; the highest concentration of Cr （VI） can be removed by dosing PAC is1mg/L. When the concentration of CrVI in the raw water changes from0.57mg/L to4.95mg/L, use4mg/L to30mg/L of FeSO₄can make the effluent water meet thenational drinking water standards. It is effective when using NaClO to removedimethyl sulfide and dimethyl disulfide.With1.0mg/L NaClO is dosing and oxidationfor1min; the removal rate of dimethyl sulfide and dimethyl sulfide can reach57.94%and92.62%.