Assessing the efficiency and efficacy of nanobubbles applied to water and wastewater treatment processes

Gases are often dissolved into water in water and wastewater treatment processes, however, it is known that poor oxygen transfer efficiency in these processes can lead to excessive amounts of air required – leading to either increased operational costs or necessary over-sizing of capital plant, or poor process performance. This is also often a major barrier to water utility uptake of processes such as ozonation – an otherwise viable and arguably safer alternative to chlorine disinfection.

In drinking water treatment, nanobubbles have potential application in:
• Backwashing of ceramic MF membranes using ozonated water
• Disinfection in the process stream
• Disinfection of long-line trunk mains
• Removal of cyanotoxins and taste & odour causing compounds for drinking water production
• NOM and colour removal
However, nanobubbles also have application in wastewater and recycled water in a wide range of treatment applications.

Nanobubble technology could also be applied for dissolving other gases into water, with the associated CAPEX and OPEX savings. However, within an Australian context, nanobubble technology has not been applied within the water sector and the potential costs and benefits, or its efficacy of use in different treatment processes has not been quantified. The purpose of this study would be to understand to what extent it can be successfully applied.