Abstract: An apparatus for treating water includes a vertically extending contact vessel, wherein water is contacted with ozone, and a return vessel which contains a column of water of a sufficient height to drive water through downstream filtering stages. Ozone is removed from the water and the rate of ozone injection is monitored and automatically adjusted so that no great amount of ozone remains in water entering the filtering stages. The ozone is generated in elongated elements that are cooled by the process water and that are positioned to serve as a static mixer for such water.

Abstract: Liquid is purified by passing it through a bed containing disc-shaped buoyant media beads having grooved surfaces. Such beads are formed from a polymeric pellets. The pellets are passed through a scarifier to roughen their surfaces. Pellets are also passed through a rolling mill which grooves the pellets and compresses them into disc-like shapes.

Abstract: Measuring device for quickly and accurately determining the thickness of an annulus between two cylindrical members, such as the catalyst retaining screens of a radial flow reactor, at any point along its length or circumference, comprises a wheeled cart having two sets of angularly mounted wheels which straddle the inner screen and a pair of spring loaded plungers with ball shaped contacts which contact the outer screen. As the device is lowered into an annulus with a cable, a pair of ultrasonic transducers positioned inside the cart direct opposed beams radially of the annulus to permit the radial distance between the screens to be measured.