No odour beyond site boundary: specialist

Fulton Hogan industries manager Peter Reid (left) and regional manager Alan Peacock (centre, both...
Fulton Hogan industries manager Peter Reid (left) and regional manager Alan Peacock (centre, both of Alexandra), show Luggate Community Association president Geoff Taylor around the site earmarked for a proposed sludge-drying facility near Luggate last year. Photo by Lucy Ibbotson.
The smell of sewage should not be evident beyond the site of a new sludge-drying plant Fulton Hogan wants to build on the Clutha River 2km from Luggate.

That is the view of Specialist Environmental Services Ltd consultant John Iseli.

Mr Iseli's report on contaminant discharges from the plant accompanies Fulton Hogan's resource consent application to the Queenstown Lakes District Council, notified last week.

The plant is intended to dry sludge trucked from the Wanaka wastewater treatment plant, near Wanaka airport.

Mr Iseli said in his report the ''Wendewolf'' solar drying plant consisted of a glasshouse where ''secondary solids'' matured for about a year.

A mechanical turning-arm would ensure they remained aerated, to help drying and to minimise odours.

The first Wendewolf plant was built in Germany in 1998 and 80 are operating around the world, three of them in Australia.

Mr Iseli said a plant at Boneo, in Victoria, Australia, of a similar size to the one proposed for Luggate, produced ''very little odour'' with no ''significant odour'' beyond the plant boundaries.

This, he said, had given Fulton Hogan confidence the Luggate plant could be operated in a way that did not cause adverse odour effects at neighbouring properties.

''A condition of consent is proposed that would require that the discharge not cause objectionable or offensive odour beyond the site boundary.''

Fulton Hogan proposes building the plant on its 46.5ha Luggate-Tarras Rd rural general site 20m above the Clutha River, downstream of the Red Bridge.

Mr Iseli said the nearest ''potentially sensitive receptors'' were at least 850m west of the site and winds in that direction occurred only about 1% of the time.

The greatest potential for odour transmission occurred in very light winds.

Mr Iseli noted potential adverse off-site effects would be associated with poor site management.

''Such effects can be controlled by implementing good-practice measures.''

One of the daily jobs for the plant operator would be to inspect the boundary ''recording any detected odour and its intensity''.

The consent application does not cover the disposal of the dried solids, which has been the prime concern of the Luggate community.

A council spokeswoman told the Otago Daily Times yesterday the end product would belong to Fulton Hogan.

The company's industries/quarries and crushing divisional manager, Pete Reid, of Alexandra, said yesterday that unless an alternative end use was found and a separate consent was obtained, the dried sludge would be sent to a landfill, as the wet sludge was at present.

The owners of two nearby farms, Kim Landreth and Paul Kane, are listed in the resource consent as being affected persons who have approved the Fulton Hogan consent application.

Mr Reid said ''no deals'' had been done with the landowners but they had shown ''an understanding and an interest in the end product as a soil enhancement mechanism to be integrated into their farming operations should the necessary consents and approvals be obtained''.


Waste not

How the sewage sludge solar drying plant works:

• The Wendewolf plant would consist of a glasshouse 108m long, 13m wide and 4m high, with a ventilation system designed to reduce the moisture content of secondary solids from about 80% to 15%.

• Would process about 1000 tonnes of sewage a year from Wanaka wastewater treatment plant.

• Average of less than 4 tonnes of secondary solids would be trucked to the plant each weekday, with peak of 14 tonnes per day.

• Delivery trucks would deposit solids inside the plant.

• Mechanical agitator would turn the solids, and fans would ''enhance'' air turbulence above the surface of the drying bed.

• Secondary solids would mature over a year and ''mature fertiliser'' would be removed from opposite end.


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