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5-4 Chlorine dioxide disinfection课程教案、知识点、字幕

同学们好!在上一节,我们介绍了最常用的消毒方法-氯消毒

除氯消毒以外,还有不少其他消毒方法

比如二氧化氯消毒法、臭氧消毒法、紫外线消毒法等

在这一节,我们将给同学们介绍另外一种消毒方法,二氧化氯消毒

二氧化氯在常温下是一种黄绿色气体,具有刺激性

而且极不稳定,气态和液态的二氧化氯均易爆炸

因此,在使用过程中,需要以水溶液的形式现场制取,即时使用

二氧化氯易溶于水,溶解度是氯的5倍

通常在水中以溶解性气体形态存在,不发生水解

二氧化氯消毒法具有以下特点

首先二氧化氯是极为有效的消毒剂,对水中的细菌和病毒的消毒效果好

pH适用范围在6-9,消毒效果仅次于臭氧,但优于或等于游离氯的效果

二氧化氯的消毒效果不受pH影响

不与氨发生反应,当水中存在氨时不影响消毒效果

在水中的稳定性仅次于氯胺,但高于游离氯,能够在管网中保持较长时间

二氧化氯既是消毒剂,又是强氧化剂

对水中多种有机物都有氧化分解作用,并且不生成三卤甲烷等消毒副产物

但二氧化氯消毒的费用比氯高

因此,很大程度上限制了该方法的大规模使用

下面介绍二氧化氯的制取方法

二氧化氯的制取方法有(以下)几种

第1种是亚氯酸钠加酸制取法

通过加盐酸或硫酸,使亚氯酸钠在酸性条件下生成二氧化氯

如下面这个公式所示

第2种是亚氯酸钠加氯制取法

以亚氯酸盐和液氯为原料,先用液氯生成次氯酸和盐酸

再与亚氯酸盐反应生成二氧化氯

如下面这两个公式所示

总的反应方程式如下

第3种是氯酸钠盐酸复合式二氧化氯制取法

将氯酸钠与盐酸进行反应,生成二氧化氯和氯气,如下

第4种是采用电解法二氧化氯发生器来制取二氧化氯

这是由次氯酸钠发生器改进而成的

通过电解食盐水,现场制取二氧化氯和次氯酸钠溶液

二氧化氯可以用于给水消毒,也可以用于废水消毒

在给水消毒中,投加量一般在0.2-0.5mg/L,接触时间不少于30min

出厂水中二氧化氯的残余量应不小于0.1mg/L,管网末梢应不小于0.02mg/L

在废水消毒中,针对二级生物处理出水

二氧化氯投加量一般控制在6-15mg/L范围内

二氧化氯消毒虽然不会生成三卤甲烷等氯代消毒副产物

但是在二氧化氯反应过程中,会生成中间产物亚氯酸根,对人体健康有害

因此亚氯酸根是二氧化氯消毒中需要控制的主要消毒副产物

在我国的《生活饮用水卫生标准》中

规定亚氯酸盐和氯酸盐的最大允许浓度均为0.7mg/L

因此,应对二氧化氯的消毒过程进行优化控制

尽量减少二氧化氯消毒副产物的产生

Water and Wastewater Treatment Engineering: Physicochemical Technology课程列表:

Chapter 0 Introduction

-0-2 Water treatment process

--0-2 Water treatment process

-0-3 Wastewater treatment process

--0-3 Wastewater treatment process

-Chap 0 Homeworks

Chapter 1 Coagulation and flocculation

-1-1 Introduction

--1-1 Introduction

-1-2 Properties of colloids

-- 1-2 Properties of colloids

-1-3 Mechanisms and process of coagulation and flocculation

--1-3 Mechanisms of coagulation and flocculation

-1-4 Coagulant and coagulant aids

-- 1-4 Coagulant and coagulant aids

-1-5 Kinetics of coagulation and flocculation

--1-5 Kinetics of coagulation and flocculation

--Announcement

-1-6 Factors affecting the coagulation performance

--1-6 Factors affecting the coagulation performance

-1-7 Facilities for coagulation and flocculation

--1-7 Facilities for coagulation and flocculation

-Chapter 1 Homeworks

Chapter 2 Sedimentation and clarification

-2-1 Introduction

--2-1 Introduction

-2-2 Discrete particle settling

--2-2 Discrete particle settling

-2-3 Flocculent settling

--2-3 Flocculent settling

-2-4 Zone settling

--2-4 zone settling

-2-5 Rectangular settling tank

--2-5 Rectangular settling tanks

-2-6 Process calculation of rectangular settling tanks

--2-6 Process calculation of rectangular settling tanks

-2-7 Vertical Flow (up-flow ) and radial flow settling tank

--2-7 Vertical Flow (up-flow ) and radial flow settling tank

-2-8 Plated sedimentation tank

--2-8 Plated sedimentation tank

-2-9 Clarification pool

--2-9 Clarification pool

-3D interactive demonstration for settling tanks

--Method for browser setting

--Up-flow settling tank

--Clarification pool

--Circular settling tank

-Chapter 2 Homework (part 1)

-Chapter 2 Homework (part 2)

Chapter 3 Air floatation

-3-1 Introduction

--3-1 Introduction

-3-2 Theoretical foundation of air floatation

--3-2 Theoretical foundation of air floatation

-3-3 Pressurized dissolved air flotation

--3-3 Pressurized dissolved air flotation

-Chapter 3 Homework

Chapter 4 Filtration

-4-1 Introduction

--4-1 Introduction

-4-2 Structure and process of conventional rapid filter

--4-2 Structure and process of conventional rapid filter

-4-3 Water head loss of filter

--4-3 Water head loss of filter

-4-4 Filtration method of filter

--4-4 Filtration method of filter

-4-5 Filter media

--4-5 Filter media

-4-6 Water distribution system

--4-6 Water distribution system

-4-7 Filter backwashing

--4-7 Filter backwashing

-4-8 Siphon filter

--4-8 Siphon filter

-4-9 Gravity valveless filter

--4-9 Gravity valveless filter

-4-10 Movable hood filter

--4-10 Movable hood filter

-3D interactive demonstration for filtration tanks

--Usage and description for 3-D demonstration

--Method for browser setting

--Conventional rapid filter

--Siphon filter

-Chapter 4 Homework

Chapter 5 Disinfection

-5-1 Introduction

--5-1 Introduction

-5-2 Influence factors of disinfection

--5-2 Influence factors of disinfection

-5-3 Chlorine disinfection

--5-3 Chlorine disinfection

--Correction

-5-4 Chlorine dioxide disinfection

--5-4 Chlorine dioxide disinfection

-5-5 Ultraviolet disinfection

--5-5 Ultraviolet disinfection

-Chapter 5 Homework

Chapter 6 Ion-exchange

-6-1 Ion-exchange resin

--6-1 Ion-exchange resin

-6-2 Properties of ion-exchange reactions

--6-2 Properties of ion-exchange reactions

-6-3 Properties of cation exchange resin

--6-3 Properties of cation exchange resin

-6-4 Properties of anion exchange resin

--6-4 Properties of anion exchange resin

-6-5 Softening system using ion exchange

--6-5 Softening system using ion exchange

-6-6 Desalination system using ion exchange

--6-6 Desalination system using ion exchange

-6-7 Ion-exchange equipment

--6-7 Ion-exchange equipment

-6-8 Treatment of industrial wastewater by ion-exchange method

--6-8 Treatment of industrial wastewater by ion-exchange method

-Chapter 6 Homework

Chapter 7 Membrane separation

-7-1 Introduction

--7-1 Introduction

-7-2 Principle and characteristics of electrodialysis

--7-2 Principle and characteristics of electrodialysis

-7-3 Configuration of electrodialysis unit

--7-3 Configuration of electrodialysis unit

-7-4 Operating parameters for electrodialysis unit

--7-4 Operating parameters for electrodialysis unit

-7-5 Principle and process of reverse osmosis

--7-5 Principle and process of reverse osmosis

-7-6 Operating parameters for reverse osmosis

--7-6 Operating parameters for reverse osmosis

-7-7 Principles and characteristics of UF and MF

--7-7 Principles and characteristics of UF and MF

-7-8 Design of ultrafiltration and microfiltration process

--7-8 Design of ultrafiltration and microfiltration process

-Chapter 7 Homework

Chapter 8 Redox method

-8-1 Fundamental knowledge and classification

--8-1 Fundamental knowledge and classification

-8-2 Ozonation

--8-2 Ozonation

-8-3 Photo-catalytic oxidation

--8-3 Photo-catalytic oxidation

-8-4 Supercritical water oxidation

--8-4 Supercritical water oxidation

-8-5 Electrolysis

--8-5 Electrolysis

-Chapter 8 Homework

Chapter 9 Adsorption

-9-1 Introduction

--9-1 Introduction

-9-2 Adsorption equilibrium and adsorption isotherm

--9-2 Adsorption equilibrium and adsorption isotherm

-9-3 Adsorption breakthrough curve

--9-3 Adsorption breakthrough curve

-Chapter 9 Homework

5-4 Chlorine dioxide disinfection笔记与讨论

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