IVER CONTACT TANK Client: Three Valleys Water Value: £4.5³¾ • Pipework and valves to allow the entire forward flow to the contact tanks to   be diverted back to the works inlet if a disinfection failure occurs. • New reinforced concrete tank, which has three flow channels created by full    height training walls and baffles, is 75 metres long, 16 metres wide and 6       metres deep and is fully submerged below ground.