《城市污水处理技术英文课件》由会员分享，可在线阅读，更多相关《城市污水处理技术英文课件（76页珍藏版）》请在金锄头文库上搜索。
1、An Introduction to Urban Water and Wastewater Treatment Technologies,2,Contents,1. Contaminants in Water 2. Contaminant Sources and Treatability 3. Best Available Technologies 4. Trend of Development,3,1. Contaminants in Water,1.1 Target of Water Quality Control,Wastewater Discharge Regulation,Key p
2、oint: Protection of human health,4,1.2 Capacity of Water Environment A simple calculation,Ci : Concentration of contaminant i Mi : Mass of contaminant i in water V : Water volume,Mi0 : Mass of contaminant i received Mir : Mass of contaminant i assimilated (removed) by the water body itself (self pur
3、ification),5,1.2 Capacity of Water Environment Water quality criteria This is equivalent to Mir is a measure of the environmental capacity,Cis : Standard for contaminant i,Mis : Maximum permissible mass of contaminant i in water,6,1.3 Water Environmental Standard American standard: Clean Water Act (
4、CWA) Ambient Water Quality Criteria for the Protection of Human Health Aquatic Life Criteria Nutrient Criteria,7,1.3 Water Environmental Standard American standard: Clean Water Act (CWA) The NRWQC 2002 includes Criteria for priority toxic pollutants: 120 items (15 for inorganic, 105 for organic poll
5、utants) Criteria for non priority pollutants: 45 items Criteria for organoleptic (taste and odor) effects: 23 items Downloadable at http:/www.epa.gov/waterscience/criteria/ wqcriteria.html,8,1.3 Water Environmental Standard Chinese standard: Environmental Quality Standards for Surface Water (GB 3838
6、-2002) Fundamental parameters (地表水环境质量标准基本项目标准限值): 24 items Supplemental parameters for source water for community water supply (集中式生活饮用水地表水源地补充项目标准限值): 5 items Specific parameters for source water for community water supply (集中式生活饮用水地表水源地特定项目标准限值): 80 items,9,表1 地表水环境质量标准基本项目标准限值 (单位: mg/L),10,表1 地
7、表水环境质量标准基本项目标准限值 (单位: mg/L),11,表1 地表水环境质量标准基本项目标准限值 (单位: mg/L),12,表2 集中式生活饮用水地表水源地补充项目标准限值 (单位：mg/L),13,表3 集中式生活饮用水地表水源地特定项目标准限值 (单位：mg/L),14,表3 集中式生活饮用水地表水源地特定项目标准限值 (单位：mg/L),15,表3 集中式生活饮用水地表水源地特定项目标准限值 (单位：mg/L),16,1.4 Pollutants of Public Concern Indicative parameters Suspended solids: SS Dissol
8、ved solids: TDS (salinity) Organic substances: COD, BOD, TOC, UV Dissolved oxygen: DO Acidity: pH Nutrients Nitrogen: TN, NH3-N, NO3-N, NO2-N Phosphorous: TP, Portho, Ppoly, Poranic ,17,1.4 Pollutants of Public Concern Synthetic organic chemicals (SOCs) Industrial products such as PCBs (Polychlorina
9、ted biphenyls) Industrial byproducts such as Dioxin Pesticides and herbicides DBP precursors Natural organic matter (NOM) such as humic acids etc. Persistent organic pollutants (POPs) DDT, PCBs, PAHs, Hexachlorobenzene, Dioxins, Furans ,18,1.4 Pollutants of Public Concern Endocrine disruptive chemic
10、als (EDCs) Heavy metals such as Cr, Pb etc. PCBs, hormones, dioxins Organo-chlorinated pesticides Microorganisms Giardia Cryptosporidium Viruses and bacteria,19,2. Contaminant Sources and Treatability,2.1 Contaminant Sources Point sources: Sources of pollutants from a discrete location such as a pip
11、e, tank, pit, or ditch. Non-point sources: Source of pollutants from a number of points that are spread out and difficult to identify and control. Non-point sources attribute a great deal to water pollution: Nutrients, pesticides, NOM Certain POPs and EDCs,20,2.2 Treatability of Pollutants The treat
12、ability of pollutants depends on their Size Suspended Colloidal Soluble Chemical properties Organic Inorganic Biodegradability Biodegradable Bio-non-degradable,21,Water quality and treatability matrix,22,Domestic wastewater as an example Methods of pollutants classification Suspended and soluble: us
13、ing a 0.45 mm filter Settleable and non-settleable: plain settling for 2 hours Coagulable and non-coagulable: coagulation and settling Secondary treatment: activated sludge process (oxidation ditch),23,24,2.3 Limitation of Conventional Treatment Conventional treatment Typical process for water treat
14、ment: Coagulation sedimentation filtration chlorination Typical process for wastewater treatment (activated sludge process): Screening primary settling biological unit secondary settling chlorination,25,2.3 Limitation of Conventional Treatment Pollutants that can be removed Suspended solids Colloida
15、l matter Biodegradable organic matter Bacteria and viruses Pollutants that cannot be removed Most of the dissolved solids Bio-non-degradable organic matter Chlorine persistent microorganisms (e. g. Cryptosporidium),26,3. Best Available Technologies,3.1 Strategic Considerations on the Selection of Av
16、ailable Technologies Conventional technologies are fundamental technologies and their enhancement should be the first choice Conversion of the property of pollutants is sometimes more important than a complete removal of the pollutants Combination of different technologies is the key for effective removal of pollutants,27,3.2 Enhancement of Conventional Technologies Enhanced coagulation For the removal of NOM in drinking water treatment For the enhancement of primary treat
