Egham Water Treatment Works Flow: 2920 m3/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?

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

Nigel describing sludge cones to class

Dual Media rapid filters Anthracite & Sand siphons (good practice)

Intermediate Ozone Building

Liquid Oxygen Tank

Liquid oxygen equipment

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 Addition of sulfur dioxide 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

Sludge Centrifuge