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1、废水处理工艺设计及计算 第6章9-11节 目录目录 CONTENTCONTENT 6-9 PHOTOLYSIS 光解 6-10 CHEMICAL NEUTRALIZATION SCALE CONTROL a balanced water will neither dissolve or form a film; a supersatured water will tend to form a film. 相关的理论包括：Langelier saturation index，Ryzner stability index，MINTEQA2，MINEQL+等。 6-10 2 2 Langelier
2、Saturation Index The tendency to develop calcium carbonate (CaCO3) scale during the advanced treatment of treated effluent can be approximated by calculating the Langelier Saturation Index (LSI). 判别标准： 1. LSI 0: 可能结垢 2. LSI 0: 不结垢，反而去除处理 单元上的水垢 3. LSI = 0: 不结垢也不除垢 LSI只用于碳酸钙水垢 总 溶 固 系 数 6-10 2 2 Ryzn
3、er Stability Index An alternative index known as the stability index was proposed by Ryzner (1944) and is used in a number of industrial applications. 判别标准： 1.RSI 5.5： 形成重垢 2.5.5 RSI 6.2： 结垢 3.6.2 RSI 6.8 ： 不结够也不除垢 4.6.8 RSI 8.5：水极容易除垢 corrosive Aggressive 指数的计算 LSI常用于 废水处理； RSI常用于 工业生产。 6-10 2 2 活度
4、系数 离子强度I 对于CaCO3（pH 6.59.0） 6-10 2 2 水垢控制 Scale Control CaCO3水垢可以通过以下几种途径去除： 1. 酸化，降低pH和碱度； 2. 通过离子交换和石灰软化，减少钙浓度； 3. 添加阻垢剂，增加CaCO3溶解度； 石灰软化法：使用石灰软化硬水的方法，在硬水中加入消石灰，与水中的硬度 成分碳酸化合物反应、生成难溶的碱性物质。使其沉淀析出，达到软化的目的 的方法，利用这种方法可使水中钙浓度降低到1035 ppm。 稳定性 Stabilization Wastewater effluent that is demineralized with
5、reverse osmosis will generally require pH and calcium carbonate adjustment to prevent metallic corrosion, due to the contact of the demineralized water with metallic pipes and equipment. Corrosion occurs because material from the solid is solubilized to satisfy the various solubility products. Demin
6、eralized water typically is stabilized by adding lime to adjust the LSI. 6-11 贮存 chemicals that are highly reactive should not be stored next to each other. 6-11 3 3 液体进料示意图 6-11 3 3 典型液体进料装置 6-11 3 3 气体进料 Gas Chemical Feed Systems Chemicals that are used as a gas include ammonia, chlorine, oxygen,
7、ozone, and sulfur dioxide. Gas feed systems are used mostly for feeding chemicals used for disinfection and dechlorination. Chlorine, a commonly used chemical for disinfection, is often supplied in a liquid form within the storage container and evaporates continuously as the gas is drawn from the he
8、adspace above the liquid in the storage container. 6-11 3 3 The optimal time for mixing can vary from a fraction of a second to several seconds or more. Because of the difficulties in achieving rapid mixing in large treatment plants with a single mixing device, the use of multiple mixing devices is recommended. The particular mixing device selected for a given application must be based on a consideration of the reaction times and operative mechanisms for the chemicals that are being used. 原料混合 Initial Chemical Mixing 废水处理工艺设计及计算 感谢各位老师评判指导 南京理工大学
