Liquid-phase technologies involve the treatment of a wastewater stream to control the release of odour and corrosion-causing compounds from the stream. They involve the addition of an element to the wastewater to either control the formation of odorous compounds or react with those compounds once they are formed. Liquid-phase treatment is most commonly applied in wastewater collection systems, not treatment plants. It often is applied in a collection system for downstream control at the headworks of a treatment plant. Since liquid-phase treatment controls the odour compounds in the wastewater itself, it provides corrosion control in addition to odour control.
With liquid-phase treatment, hydrogen sulphide is prevented from escaping the liquid into the vapour, therefore it is not present to cause corrosion on process structures, pipe crowns, etc. Through proper application of a liquid-phase treatment in a collection system, multiple odour release points such as manholes, air relief valves and re-pump stations can be controlled through one or more strategic application points.