Clariant uses water for a variety of purposes in the production of chemical products, and the water is partly polluted as a result. At each site, therefore, production waste water is first subject to multistage chemical-physical pre-cleaning before being routed to largely biological waste water treatment plants, where it is micro-biologically cleaned. Water that is only used for cooling can be directly released into rivers because it has not come in contact with chemicals. To prevent contamination of the intake water through undetected leaks in the cooling system, the cooling water and rainwater are constantly analyzed at the individual sites as an additional safety measure. If contamination is discovered, discharge into the rivers can be prevented by various containment systems.

The absolute and relative quantity of water used (in relation to production) clearly declined in the period from 2013 to 2015. The amount of total waste water in 2015 came to 13.3 million m³ or 3.6 m³ per manufactured ton of production compared to 20 million m³ or 4.9 m³ per t in 2013.

Clariant reduced the chemical oxygen demand (COD), the measurement for the degree of waste water burdened with organic substances, in all waste water treatment plants by more than 65 % in the years from 2005 until 2015. The fees, and as a consequence, also the production costs are lowered therewith. Only small amounts of heavy metals remain in the waste water at Clariant’s individual sites. The projected values are partly based on concentrations that are at or below the detection limit. The waste water discharged by Clariant is largely cleaned and therefore is not a particular burden. Thus, Clariant has already achieved a very high level in terms of waste water treatment and water purification.