Online Monitoring of Wastewater Effluent Chlorination Using Oxidation Reduction Potential (ORP) vs. Residual Chlorine Measurement
( WERF Research Report Series )
Publication series ：WERF Research Report Series
Author： Damon S. Williams
Publisher： IWA Publishing
Publication year： 2005
E-ISBN: 9781843397175
Subject： X703 Wastewater treatment and reuse
Keyword： 工业技术
Language： ENG
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Online Monitoring of Wastewater Effluent Chlorination Using Oxidation Reduction Potential (ORP) vs. Residual Chlorine Measurement
Description
Various control strategies are employed to insure that a sufficient amount of chlorine has been applied to the wastewater effluent to achieve desired disinfection goals. In the commonly used control strategies, such as Feed Back Control and Compound Loop Control, the combination of effluent flow rate, chlorine flow rate and chlorine residual are measured for dosing control with the chlorine residual used as a set point parameter. Recently Oxidation-Reduction Potential (ORP) has been employed as a control measurement and set point parameter for effluent chlorine dosing control as well. Theoretically, use of chlorine residual or ORP set point makes the chlorine dosing possible to simultaneously respond to changes in effluent flow rate and in process (such as fluctuating effluent ammonia levels), which cause variations in chlorine demand and thus the ORP or chlorine residual after the dose point. This would also potentially reduce chlorine feed requirements. Specific ORP or residual chlorine residual levels to ensure effective disinfection could be effectively monitored and maintained under changing effluent quality conditions. In addition, immediate detection of chlorine feed malfunction could be achieved when analyzers are employed at the chlorine dosing point. Despite all these advantages, many wastewater treatment plants have chosen not to use signals from chlorine residual or ORP analyzers or results from manual grab chlorine residual testing for their chlorine dosing cont
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