Early warning system sniffs out waste water hazards

A diagnostic monitor designed to give engineers an early warning that hazardous untreated ammonia could seep into water supplies is to be commercialised this year.

The N-Tox monitor, which warns of a failure in the nitrification process, is being developed by Water Innovate, a spin-out of the school of water sciences at Cranfield University.

The monitor comprises a hood that uses gas-phase technology to detect nitrous oxide, which is produced if the biological process of converting ammonia into nitrates fails. It analyses the gas that is emitted during the nitrification process as the ammonia is converted and passes it through a sensor to detect the presence of nitrous oxide.

This will give engineers at treatment plants several hours head-start over existing monitors to correct a fault.

The monitor is one of six new technologies for the treatment of waste water and sewage developed by Water Innovate. The most advanced of these is OdourSim, a software package that can predict odours from sewage works and create ‘odour maps’ similar to weather charts.

The detailed odour contour maps are produced by processing data based on variables including weather conditions, flow rate and the physical parameters of the treatment works itself, such as the size of the sedimentation tanks and filters. Water

Innovate managing director Dr Steve Callister said: ‘Existing odour-prediction technology only looks at dispersion data. To get an accurate contour plot from your dispersion model you need to have accurate time-varying data, which takes every possible variable into account. OdourSim is the only package which can do that.’

Both N-Tox and OdourSim have been trialled at Severn Trent Water sites. The company is also developing the Membrane Chemical Reactor, which removes odour-causing molecules from air, and could have potential applications for odour control in the oil and gas industries.