Energy & Environment

Treatment of micro-pollutants, residual colour, disinfection - Ozono

The use of ozone produced from pure oxygen in the treatment and elimination of micro-pollutants in wastewater, for example surfactants, non-biodegradable COD, residual colour, or in final disinfection processes, is a technology that often has to be applied in wastewater treatment plants as a tertiary stage, and in certain situations even prior to the biological stage, in particular to increase the BOD/COD ratio of the water to be treated.

Ozone is a strongly oxidising gas produced from oxygen by using electrical energy. It is an unstable molecule that tends to decompose spontaneously re-forming oxygen (half-life at 20°C: about 30 minutes), and so cannot be stored but needs to be produced directly on site.

The most modern ozone production technologies permit degrees of conversion of the pure oxygen used of over 16%, and usage efficiency levels close to 100% . In particular, the production of ozone from pure oxygen considerably limits both the investment costs and the electrical consumption of the ozone production system compared with air-fed systems. The specific characteristics of the oxygen supplied by SOL also make it possible to prolong the working life of the plant thanks to the very low humidity content which, if present in potentially uncontrolled quantities, for example when using compressed air, can lead to frequent breakdowns.

Employing Ecojet® technology, it is also possible to reuse, for example in a water purifying plant, the oxygen released from the plant after the dissolution and use of the ozone: this means further savings and an increase in the overall efficiency of the treatment.