• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Understanding and optimizing preoxidation for disinfection byproduct control.
【24h】

Understanding and optimizing preoxidation for disinfection byproduct control.

机译：了解和优化用于消毒副产物控制的预氧化。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

To minimize disinfection byproduct (DBP) formation three relatively inexpensive options are available to drinking water treatment plants that chlorinate prior to or at the rapid mix: (1) lower the level of chlorine added, (2) move the point of chlorination to after the sedimentation basin, and (3) switch to a different disinfectant/preoxidant. Bench- and pilot-scale studies demonstrated that DBP formation, as measured by total trihalomethanes (TTHM) and the nine haloacetic acids (HAA9) could be controlled through an optimized approach to prechlorination. For the purposes of comparison all dosing approaches targeted a 24-hour 1 mg/L chlorine residual. The worst-case dosing scenario, in which all the chlorine was dosed up front at the rapid mix, was used as the benchmark for comparison. The disinfection byproduct (DBP) formation results indicated that lowering the prechlorination dose (while still applying chlorine as a preoxidant) and re-chlorinating after the sedimentation basin to yield the target distribution system residual yielded lower chlorine consumed (up to 41%) and lower TTHM and HAA9 (up to 51%) formed after 5 days. Using potassium permanganate as a preoxidant yielded similar DBP formation compared to solely applying chlorine after sedimentation. The use of chlorine dioxide, however, yielded the lowest DBP formation for most of the waters tested; average reductions of 50 to 60% were seen for TTHM and HAA9.; Chlorine and chlorine dioxide react with natural organic matter to form DBPs, some of which are characterized, e.g., trihalomethanes (THMs) and haloacetic acids (HAAs) and others that can only be assessed with the adsorbable organic halogen (AOX) measurement. The fate of these DBPs was addressed during alum coagulation of five natural waters. THMs and HAAs preformed in the raw waters were found not to be removed by coagulation, while the uncharacterized AOX (AOX-U), calculated as the difference between the AOX concentration and the THM and HAA concentrations, was effectively removed. Near complete AOX-U removal was achieved by increasing the alum dose. AOX was found not to desorb from the floc. Once flocs were formed, no removal of the DBPs occurred, indicating that adsorption on the aluminum hydroxide precipitate was not the AOX removal mechanism, but that co-precipitation dominated. Chlorine was found to react directly with the flocs to produce a small amount of THMs and HAAs, but not to produce AOX-U.
机译：为了最大程度地减少形成消毒副产物（DBP）的可能性，饮用水处理厂可以在快速混合之前或快速混合之前进行氯化处理，提供三种相对便宜的选择：（1）降低所添加的氯含量，（2）将氯化点移至（3）切换到其他消毒剂/预氧化剂。基准和中试规模的研究表明，可以通过优化的预氯化方法来控制以总三卤甲烷（TTHM）和九种卤代乙酸（HAA9）衡量的DBP形成。为了进行比较，所有加药方法均以24小时1 mg / L的氯残留量为目标。在最坏情况下的投加方案中，所有氯都是在快速混合时预先添加的，被用作比较的基准。消毒副产物（DBP）的形成结果表明，降低预氯化剂量（同时仍使用氯作为预氧化剂）并在沉淀池后再进行氯化以产生目标分配系统残余物，从而可以降低氯的消耗量（最高41％），并降低5天后形成TTHM和HAA9（最高51％）。与高锰酸钾作为预氧化剂相比，在沉淀后仅施用氯气可产生相似的DBP形成。然而，在大多数测试水中，使用二氧化氯产生的DBP最少。 TTHM和HAA9平均减少了50％至60％。氯和二氧化氯与天然有机物发生反应形成DBP，其中一些具有特征，例如三卤甲烷（THM）和卤代乙酸（HAA），而另一些只能通过可吸收有机卤素（AOX）进行评估。这些DBP的命运在五个天然水的明矾凝结过程中得到了解决。发现原水中未形成THMs和HAA，但不能通过凝结去除，而以AOX浓度与THM和HAA浓度之间的差计算的未表征的AOX（AOX-U）被有效去除。通过增加明矾剂量，几乎可以完全去除AOX-U。发现AOX不会从絮凝物中解吸。一旦形成絮凝物，就不会发生DBP的去除，这表明氢氧化铝沉淀物上的吸附不是AOX去除机理，而是共沉淀作用占主导。发现氯直接与絮凝物反应生成少量THM和HAA，但不生成AOX-U。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号