Primox® is a system for oxygenating sewage within the sewerage system itself. 

The oxygen is usually injected into rising mains. Primox® provides an effective means of preventing septicity as well as an economic method of pre-treatment of sewage before it arrives at a works.

When starved of dissolved oxygen, particularly in longer mains or where long retention takes place, bacterial action can strip out the combined oxygen from the sulphates and nitrates in the sewage, producing sulphides and other harmful compounds. The result is septicity, foul odours and a sewage with poor settling characteristics.

Primox® was developed by BOC to overcome this. Using very simple equipment, it injects oxygen at the base of the rising main in quantities sufficient to maintain aerobic conditions through its entire length.  Primox® technology provides facultative bacteria with substantial quantities of dissolved oxygen for aerobic respiration during the retention period in the main, thus preventing anaerobic conditions and the consequent generation of sulphides.

Unlike chemical-in-main treatments, which only control sulphide generation, oxygen additionally breaks down complex organic compounds into less harmful products and controls odours further down the reticulation system.