Research On Emergency Pretreatment Measures For Sudden Pollution Incidents In Xi’jiu

People’s living standards gradually improved, the demand of domestic water quality and quantity also rises gradually. Reservoir water is used mostly as source water in most parts of China, ene of the most common problems that almost every city facing now is the supply shortage of domestic water caused by inter-annual rainfall changes. So, in order to handle such problems like this, a lot of water plants set alternate source water system to respond to emergencies. Some southern regions, including Jiangsu, Shanghai, lakes near the waterworks plant are usually chosen to be alternate source water. From investigating and analysis, recessive pollution exists in the upstream of lake and around the lake, so the organic or inorganic pollution incidents that may happen in emergency backup water source should not be ignored.By taking back up water source-----Xi Jiu Lake in Yixing city, Jiangsu Province as research object, this project aims to solve the problems which are mentioned above by researching emergency water quality pretreatment method, which are based on powder activated carbon adsorption, advanced oxidation and their combination; the coordination of emergency water quality pretreatment method and the conventional water treatment method; research for the coordination of emergency water quality pretreatment method and the conventional water treatment method on pilot test, aiming to handle the pollution incidents that may occur in back up water source----Xi Jiu Lake, such as CODMn, ammonium, pesticide and chemical industry sudden pollution. This treatment process investigated coagulation-sedimentation, Modification of powder activated carbon adsorption and ozone oxidation with different kinds of catalytic oxidation of pharmacy respectively. The pilot site is set in the Jiubin waterfront factory in Yixing city.The analysis data showed that, the current conventional water treatment process has severe shortcomings and limitation for treating water suddenly polluted by CODMn, ammonium, aniline and glyphosate. When using ozonation alone or using powdered activated carbon alone to remove 1~20mg/L CODMn and ammonium, the removal rate of CODMn and ammonium all stay in 0~10%, low removal rate; slow reaction rate; high disinfection by-products; excessive drug dosage are also existed when treating aniline and glyphosate, all of these shortcomings obviously cannot meet demand of emergency pretreatment. The project are aiming to find a new cost-efficient way to optimize existing water treatment technology by continue on debugging and tuning parameters.The experimental results show that:(1) Using 6mg/min O3 + 3mg/L H2O2 to remove 20mg/L CODMn, the removal rate of it reaches 49%, the removal efficiency can be best when mole ratio of H2O2 and O3 is 0.7.(2) Compared to usual powdered activated carbon, the powdered activated carbon which is modified by physical and chemical means has rises with different degrees when remove CODMn sudden pollution.(3) When mole ratio of nitrogen and chlorine dosage is 1:5.5, the removal rate of 1~25mg/L ammoniacal nitrogen reaches 98% above when accompanied with 4mg/min O3, the TN can also be removed 40% above in this way.(4) For 1~80mg/L glyphosate sudden pollution, when mole ratio of glyphosate and chlorine dosage is 1:6.25, accompanied with 3.5mg/min O3, the glyphosate in effluent which comes out from coagulation-sedimentation with polyaluminium chloride and calcium hydroxide can be removed 98.7% above.(5) Ozone + sodium hypochlorite can 100% remove aniline sudden pollution.