egham water treatment works flow: 2920 m 3 /h. source thames river
Post on 21-Dec-2015
221 views
TRANSCRIPT
Pre-ozone in-line injector
• Purpose: to help with coagulation
• They also add pre chlorine to breakpoint any ammonia– needed ~80% of time?
Pre-O3 injector and static mixer
• 4 elements• 700 mm diameter
• 196 mbar headloss• 97% transfer efficiency
Gravity Settling Tanks
• Sludge blanket
• submerged conical sludge collectors– can be barely
seen here– suspended
from above
Intermediate O3 Monitor
• Purpose of inter ozone: disinfection
• criteria: 0.4 mg/L residual after 4 minutes in contact tank
Final Disinfection
• Free chlorine– shoot for a residual of about 0.5 mg/L– requires a dose of ~ 2-3 mg/L
• Addition of sulfur dioxide– to achieve target FRC
• THMs are low (~30 ug/L)– except when prechlorinating– final pH is about 7