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Egham Water Treatment Works. Flow: 2920 m 3 /h. Source. Thames River. Screening. With surface boom. Rotating Mesh Screen. Debris from Screens. Pre-ozone in-line injector. Purpose: to help with coagulation They also add pre chlorine to breakpoint any ammonia needed ~80% of time?.
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Egham Water Treatment Works Flow: 2920 m3/h
Source • Thames River
Screening • With surface boom
Pre-ozone in-line injector • Purpose: to help with coagulation • They also add pre chlorine to breakpoint any ammonia • needed ~80% of time?
4 elements 700 mm diameter 196 mbar headloss 97% transfer efficiency Pre-O3 injector and static mixer
Gravity Settling Tanks • Sludge blanket • submerged conical sludge collectors • can be barely seen here • suspended from above
Dual Media rapid filters • Anthracite & Sand • siphons (good practice)
LOX handling • Heat transfer
Ozone Generator • Trailigaz • One of 3 units • only one in use that day
Ozone Generator • No blue glow, because of pure O2
Intermediate O3 Monitor • Purpose of inter ozone: disinfection • criteria: 0.4 mg/L residual after 4 minutes in contact tank
GAC contactors • Modular design • Avoided need for expensive in place concrete • problems with leaks
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