Wastewater Treatment Plants & Bacteria: Strategies for Compliance Chlorine Contact Chambers; Chlorine Mixing and Contact Time for Ct Harris County Wastewater Symposium Wastewater Treatment Plants & Bacteria: Strategies for Compliance Tim Brodeur, PE April 26, 2011
15
Embed
Wastewater Treatment Plants & Bacteria: Strategies for Compliance Chlorine Contact Chambers; Chlorine Mixing and Contact Time for Ct Harris County Wastewater.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Wastewater Treatment Plants & Bacteria: Strategies for Compliance
Chlorine Contact Chambers; Chlorine Mixing and Contact Time for CtHarris County Wastewater SymposiumWastewater Treatment Plants & Bacteria: Strategies for ComplianceTim Brodeur, PEApril 26, 2011
Wastewater Treatment Plants & Bacteria: Strategies for Compliance
Chlorine Contact Chambers Identify operational and design improvements associated with the disinfection process to help struggling WWTPs meet the new Coliform requirements
• Goals of this Section:• Identify issues that promote ineffective bacteria
reduction• Identify operational solutions that can be implemented
tomorrow• Identify design solutions and retrofits for existing
WWTPs• Identify design solutions to be implemented on your
next “Greenfield” design
Wastewater Treatment Plants & Bacteria: Strategies for Compliance
Disinfection Performance Comparison:
Free Chlorine vs. Chloramines
Wastewater Treatment Plants & Bacteria: Strategies for Compliance
Chlorine Injection and Mixing
– Design considerations• Proper Mixing
– Reduces off-gassing (Cl2, if gas is used)– Reduces formation of di- and tri-chloramines– Increases formation of hypochlorous acid (stronger disinfectant); less
hypochlorite ion
• Recommended level of mixing:– G-value: 500 s-1: Required by Texas CEQ– In-pipe injection ahead of a hydraulic jump w/ 2 ft. head loss
• Which is a better source of water for creating your chlorine solution: pre-injection point water or post-injection point water? – Post Injection
Wastewater Treatment Plants & Bacteria: Strategies for Compliance
Chlorine Injection and Mixing
– Operation considerations• Relocation of chlorine
injection point further up-stream– Results in longer contact
time
• Achieve break-point chlorination– Results in a stronger
disinfection agent
Wastewater Treatment Plants & Bacteria: Strategies for Compliance
Injection and Mixing
Wastewater Treatment Plants & Bacteria: Strategies for Compliance