Disinfection Of Drinking Water PDF

Disinfection of Drinking Water  Two categories for selected source water, surface water and groundwater. They all requires purification and disinfection, sometimes special treatments. Choose of water source: easily to take the improvement of water quality, ensure good wate...

Disinfection of Drinking Water  Two categories for selected source water, surface water and groundwater. They all requires purification and disinfection, sometimes special treatments. Choose of water source: easily to take the improvement of water quality, ensure good water quality; use water conveniently; easily supervise and manage the hygiene. Four stages of water treatment ： including coagulation, sedimentation, filtration, and disinfection.  Conception Disinfection ： Method of killing pathogenic microorganisms in the environment. Method of drinking water disinfect in China ？  physical disinfection: boiling, ultraviolet  chemical disinfection: chlorine, chlorine dioxide, ozone Which kind of disinfectants are used in China?  liquid chlorine, bleaching powder, bleaching powder concentrate  Conception When chlorine is added to water, there is formation of hydrochloric and hypochlorous acids. The hypochlorous acid ionizes to form hydrogen ions and hypochlorite ions, as follows: Cl2+H2O→HOC1+ H+ + OC1- Bleaching powder and bleaching powder detergent are turned into hypochlorous acid in the water 2Ca(OCl)Cl 十 2 H2O → Ca(OH )2 十 2 HOC1 十 CaCl2 Ca(OCl)2 十 2H2O → Ca (OH )2 十 2HOCl  Concept of Chlorination disinfection Bactericidal effect of chlorine ： The component of chlorine compounds have the ability to killing bacterium. Amount of required chlorine ： Chlorine demand refers to the amount of available chlorine consumed by the oxidation of organic matters and reduced inorganic matters water. Residual chlorine refers to the rest of active chlorine in water after adding chlorine to disinfect for a certain period of time. The total of these chlorine is the amount of required chlorine.  Concept of Chlorination disinfection Residual chlorine: The rest of active chlorine in water after adding chlorine to disinfect for a certain period of time to preventing bacteria regeneration and reproduction.  Principle To take a certain number of copies and certain volume of water samples. Then the water samples were added different amounts of a known concentration of bleach power dilution, after a certain period of time to achieve disinfection effect. After 30 minutes, we detect the residual chlorine. The best water samples for disinfection is the concentration residual chlorine 0.3 mg/L. From observing the chlorine water samples, and predicating which is most appropriate residual chlorine water samples, then calculating the amount of chlorine bleach solution.  Principle Method of detecting residual chlorine: the residual chlorine in water can react with o-tolidine role biphenyl quinone( 邻联甲苯胺 ) ， and produce yellow diphenoquinone （连苯醌） compound Colorimetric quantification based on the color depth. （ Residual Chlorine Comparator 余氯 比色器）  Materials Erlenmeyer flask （三角烧瓶） 250 mL 5 volumetric(al) cylinder （量筒） 100 mL 1 measuring pipet （吸量管） 5 mL 1 Residual Chlorine Comparator 1 （余氯比色器） Graduated tube （刻度管） 10 mL 5  Reagents 0.01% Bleach solution 0.01g Bleath power+little distilled water, triturating Volume with distilled water to 100 mL 0.1% o-tolidine role biphenyl quinone solution( 邻联甲 苯胺溶液 ) 1.00g o-tolidine role biphenyl quinone solution + 5 mL HCl （ 3:7 ） , triturating+ 495 mL HCl （ 3:7 ） , 1000 mL volumetric(al) cylinder, Volume with distilled water to 1000 mL Store in brown bottle, room temperature  Procedure 5 Erlenmeyer flask ， add 100 mL water sample, respectively Add 0.01% Bleach solution 0.5 、 1.0 、 1.5 、 2.0 、 2.5 mL, respectively Mixing ， Placing for 30 minutes 5 Graduated tube ， adding 0.5 mL （ 10 drip ） o-tolidine role biphenyl quinone solution, respectively Volume with disinfected water sample to 10 mL ， Mixing ， Placing for 10 minutes Using Residual Chlorine Comparator to detect the color depeth The best dose of Bleach solution is the concentration residual chlorine 0.3mg/L The formula for Bleach power dose Bleach disinfectant dose needed for Disinfection(mg/L)=1000*C*V/100 C(mg/mL): Bleach solution concentration, 0.1 mg/mL V (mL): The volume of bleach solution for residual chlorine 0.3 mg/L water sample.  Precautions Residual Chlorine Comparator is rough measurement instruments Residual chlorine amount of 0.3 mg/L in water after disinfection is the most appropriate disinfection. Please handle with care for Residual Chlorine Comparator Experimental Report ( 实验报告 ) Principle Experimental Procedure The experimental results