3.5a卫生(中英文).ppt

* * * * * * * * * * * * * * * * * Chlorination Chlorine Dosage: Total amount of chlorine added to water Chlorine Demand: Amount required to react with inorganic impurities Influenced by impurities, contact time, water pH and temperature Chlorine Residual: Amount remaining after chlorine demand has been satisfied Residual = Dosage - Demand 余氯 以结合形式或游离残留形式存在 结合 – 与有机杂质反应了的氯 具有相对较弱的杀菌性能 游离 - 没有和有机物反应的氯 杀菌力和浓度成正比 Residual Chlorine Exists as either combined or free residual chlorine Combined – chlorine that has reacted with organic impurities Possesses relatively weaker germicidal properties Free - chlorine that has not reacted with organic matter Germicidal properties are proportional to concentration 折点氯化法 游离残留氯 = 剂量 – 需量（耗量） 必须加入充足的氯同所有杂质反应: 超过折点加入的氯以游离余氯形式存在. Break Point Chlorination Free Residual = Dosage - Demand Sufficient chlorine must be added to react with all impurities: anything added beyond that point (break point”) exists as free residual chlorine. 氯化作用影响因素 氯的杀菌力受下述影响: 加氯浓度 氯水pH 呈现的有机物和无机物 水温度 Factors in Chlorination The germicidal properties of chlorine are affected by: Concentration of added chlorine pH of chlorinated water Organic and inorganic matter present Temperature of water pH对水中游离有效氯的影响 % HOCl Cl2 HOCL OCL- pH Effect of pH on Free Available Chlorine in Water % HOCl Cl2 HOCL OCL- pH pH 对钝化细菌的影响 0 100 1000 10000 Time (min) Survivors pH 8.0 pH 6.0 5 10 15 20 25 30 35 40 45 Effect of pH on Inactivation of Bacteria 0 100 1000 10000 Time (min) Survivors pH 8.0 pH 6.0 5 10 15 20 25 30 35 40 45 有机物对钝化细菌的影响 0 100 1000 10000 Time (min) Tomato Juice Buffer pH 7 5 10 15 20 25 30 35 40 45 5% Starch Solution 40% Sugar Solution Effect of Organic Matter on Inactivation of Bacteria 0 100 1000 10000 Time (min) Tomato Juice Buffer pH 7 5 10 15 20 25 30 35 40 45 5% Starch Solution 40% Sugar Solution 温度对氯溶解性影响 Effect of Temperature on Solubility of Chlorine 容器冷却水的氯化 Chlorination of Container Cooling Water 冷却水中细菌的显著性 我们不可能持续做到完美的真空密封 即使可接受的密封也不能防止重度污染的冷却水造成漏罐腐败