Now more than ever waste water needs to be treated before release or recycling. This presents many problems where most biological processes do not provide a complete solution. Ozone can be used to enhance the process in several ways. Firstly in pre-treatment by oxidising waste, including antibiotics, while raising oxygen levels and promoting sedimentation / flotation effects. Secondly as tertiary treatment to address issues such as BOD or COD levels, colouration, odour etc. before discharge.