ABSTRACT
Sewage with high chemical reqirements for oxygen /CRO/ and high content of halogenie hydrocarbons, e. r. effluents from dumping sites of groud waters with high content of polocylic hydrocarbons can be purfied with ozone alone or in combination with ultraviolet radoation or in combination with biological processing, UV and ozone. These methods enable the effluents to be processed properly from the ecological as well as economic standpoits, and the obtained values of CRO, CRO and WWA meet the reqirements set down in regulations.