The Mangawhai wastewater sewer network is a combination of pressure sewers and a gravity network. The main pump station at Mangawhai Village is located just 10 metres from a gift shop. There were odour complaints from this pump station as soon as it originally started operation. The pump station handles inflows from both gravity sewers and pressure sewers, and pumps directly to the main Mangawhai wastewater pump station, near the wastewater treatment plant. The area is mainly a holiday destination, with its population increasing dramatically in summer months.
To solve the challenge, the operators required the following key requirements for an odour filter be met: that it had minimum maintenance, low operating costs and low visual impact.
Armatec installed a GDOF-24 Green Dome Odour Filter connected directly to the pump station with an underground duct, treating the air as it is physically displaced from the pump station when the water level rises. A larger GDOF was installed on a second pump station in close-by area in Mangawhai.
The Green Domes were installed partly underground, with the ducting from the pump station totally underground, minimising visual impact. A domed lid covering the top of the carbon bed is all that is visible.
Constructed in corrosion resistant fibreglass, all parts are designed to have a very low pressure drop, ensuring as much air as possible exits the pump station via the carbon bed.
The outcome has been wonderful for the shops, neighbours and visitors - with all odour issues removed.
The gift shop attendant noted: "The odour was gone as soon as it was installed. There is no odour whatsoever, in comparison to how it was. It is just fantastic. It was a horrible smell. It made the working environment really hard to work in. Customers would always comment on it."
Following the first two successful Green Domes at Mangawhai in 2010, over 50 Green Domes have now been installed throughout New Zealand and Australia eliminating odours released from pump stations, air release valves and manholes.