Water-purifying ozone column. Chemical engineer Chedly Tizaoui holding a column of organic pollutant-destroying ozone beads. The column will treat any waste water or industrial effluent passed through it. Each of the 2 millimetre- diameter silica beads has ozone, a highly reactive form of oxygen, adsorbed on its surface. This technique is ten times more potent than pumping ozone through waste water, where only 10 per cent of the ozone dissolves and attacks the pollution. As the ozone is used up, the blue beads fade in colour. A white appearance means that they must be recharged. Tizaoui heads the team from Bradford University, England, that developed the process.