Odour control for pump stations

In any wastewater pump station, as the water level rises before the pumping cycle starts, odourous air is displaced. This odour can cause a nuisance for neighbours. The main odourous compound is H2S (hydrogen sulphide), present at concentrations up to 100 ppm, and occasionally higher. Odour control technologies, such as carbon beds, biological scrubbers, and soil bed filters, are required to mitigate the odour nuisance.

H2S concentrations were logged at two pump stations to obtain data for LCC (life cycle cost) analysis. At the ‘larger’ Otumanga pump station, a biological scrubber, and later a carbon bed adsorber were installed and monitored. At the ‘smaller’ Mangawhai Village pump station, a passive (no fan) carbon bed adsorber was installed and monitored.

The carbon bed adsorber removed greater than 99.9% of the H2S, and eliminated the odour nuisance. The biological scrubber successfully eliminated the odour nuisance when coupled with a final carbon bed polishing unit.

A carbon bed adsorber has the lowest LCC for a pump station with a PDWF (peak dry weather flow) of 100 l/s or less, and an average H2S concentration of less than 10 ppm.