Study On The Effect And Mechanism Of Ozone Pre Oxidation For Removing Odor In Drinking Water

Drinking water safety has been a hot issue. However, with the continuous improvement of the economic level of Taihu Lake, water pollution is increasingly serious. The problem of the smell of the algae has greatly affected the water quality of the water source, the Taihu Lake drinking water safety is a serious threat.This study takes Taihu water as an example, in the Suzhou test simulation of a waterworks, with a small pilot test, a comprehensive exploration of the mechanism and effect on the removal of odor substances of the ozone pretreatment, so as to provide a theoretical basis for the water plant to water odor problems.Through the investigation of the source of water and sediment, analysis Water Supply Source conventional physical and chemical characteristics, nutrients and sediment in the water taste and odor compounds 2-methylisoborneol?2-MIB? and geosmin?GSM?.The results showed that the conventional physical and chemical characteristics of the water source area were good, and the content of algae in summer increased, the highest was 300 thousand /L, the highest TN was 2.2mg/L, the highest TP was 0.05mg/L, the highest NH₃-N was 0.15mg/L, and the content of nutrient salt was stable, Water quality of the water source to meet the "Surface Water Quality Standard" GB3838-2002 type of ? water standards.Water and Sediments main odor substance is 2-MIB, and the water taste and odor compounds were normalized trend.There are two main points: one is the odor of the algae blooms in summer, and the two is the release of the sediment from the bottom of the spring.Through pilot simulation water process, studied pre ozone and conventional technology?coagulation, sedimentation, sand filtration? for 2-MIB, GSM and organic matter removal efficiency. The results showed that the removal rate of GSM and 2-MIB was 34% and 34.8% respectively when the ozone dosage was 0.56mg/L.At this point, the removal rates of TOC, COD_Mn and UV₂₅₄ were 6.5%, 7.07%, 3.35%,and the 0.56mg/L of ozone increased the molecular weight of organic compounds under the action of micro flocculation, the content of organic matter and turbidity increased. After the pre-ozone conventional process for 2-MIB, GSM removal rates were 63.05%, 65.25%, then the conventional process for 2-MIB, GSM accumulated removal rates were 93.1%, 95.3%. The odor concentration of the sand filter is about10ng/L, and most of them are lower than the threshold value. The ozone 0.56mg/L in this process play the role of coagulation aid, the sedimentation water ? potentialdecreased from-5.99 mv to-4.09 mv, the turbidity decreased from 1.41 NTU to0.79 NTU.Through pilot test, to study the factors affecting of the ozone oxidation of 2-MIB and its oxidation pathway. The results show that the oxidation time of ozone oxidation for 2-MIB 20 min, natural water contribute to ozone oxidation of 2-MIB, p H value of ozone oxidation of 2-MIB better neutral and weak alkaline. When p H was 8.5, the removal rate of 2-MIB by 0.56mg/L was 35%. Ozone oxidation is mainly based on the indirect oxidation of hydroxyl radicals, direct oxidation of ozone molecules is complementary, of which the former accounted for 70%, which accounted for 30%.The ozone oxidation of 2-MIB to camphor substances with a double bridge structure.