Expert clears air over odour

A modern rendering plant should not emit objectionable odours beyond its boundaries an expert appearing for a company wanting to build a such an operation in Washdyke, Timaru, has told an independent hearings panel.

Roger Cudmore, who has specialised in environmental management, in particular Odour Control Systems (OCS), told the hearing’s panel yesterday that Southern Protein Ltd’s OCS would be designed to avoid causing objectionable or offensive odour beyond the site boundary.

SPL is seeking discharge to air consents for the proposed $34 million plant before Environment Canterbury-appointed independent hearings commissioners John Iseli and Gina Solomon.

Cudmore, who said he had direct experience in assessing and advising on odour effects associated with the rendering industry in New Zealand and in Australia, had confidence in the design of SPL’s odour control systems.

He said the conditions proposed for the plant would provide real-time information, and enable proactive maintenance.

Iseli asked Cudmore whether he was confident that there would be no objectionable odour beyond the boundary.

Cudmore replied he was ‘‘extremely’’ confident, as long as the plant was kept up to date.

‘‘I’ve been doing this for 20 years, when you get the point source designed and maintain it, raw material doesn’t produce odours,’’ he said.

‘‘It’s only after years of neglect. It’s highly unlikely you will get problems as long as you maintain that system.’’

Cudmore said the industrial neighbours surrounding the proposed plant at 144 Meadows Rd in Washdyke, would have ‘‘one of the lowest potentials for odour exposure’’, adding that he believed SPL’s OCS and the OCS at another rendering plant in the vicinity were designed and sized differently.

Iseli asked if the proposed plant would experience ‘‘residual odours’’ masked by the biofilter process.

Cudmore replied: ‘‘It just shouldn’t be there.

‘‘The minute you smell the rendering odour, you should be worried. You would have a byproduct that’s not being processed properly.

‘‘The proposed conditions are designed to stop that loss of control – it’s like a new car, it will only work as long as it’s maintained.’’

Cudmore said the plant’s biofilters would routinely remove 100 per cent of odour associated with rendering, and leave only a slight ‘‘bark-like’’ odour.

Solomon asked Cudmore whether it was easy for the plant

‘‘It’s highly unlikely you will get problems as long as you maintain that system.’’ Roger Cudmore

Environmental management specialist

to detect the objectionable odours.

Cudmore said it was easy to not only discern the type of odour but also where it comes from.

‘‘You get to know a rendering odour very quickly. It would be easy to detect whether an odour was coming from us . . . ’’

Cudmore said the nearest isolated residential dwelling is a significant distance to the southwest of the site (380 metres from SPL), and is situated within the Industrial H zone.

‘‘Further, this dwelling is only downwind of the site for 3.5 per cent of time when wind speed is 5 metres per second, or less.

‘‘Winds below 3m/s, which cause the greatest potential for fugitive odour to be experienced downwind occurs infrequently (less than 0.5 per cent of the time).

‘‘Any odours from SPL are likely to be weak to very weak and rarely occurring, and likely to cause minor or less effects.’’

In response, Iseli said: ‘‘If I was in my residential property, and I was being exposed to a distinct rendering odour for 3 per cent of the time, I can imagine being annoyed.’’

Cudmore agreed and said the aim was to have no odours.

‘‘In 2020, a well-designed rendering plant should not be emitting odours off the site of the property that is objectionable.’’

SPL general manager Gordon Henderson said if the consent was granted, he would move to Timaru and manage the plant.

‘‘I am absolutely committed to consent compliance as well as developing a good relationship with residents and businesses within the Washdyke community,’’ Henderson said.

‘‘I intend to hold six-monthly community liaison meetings so I can report to the community about our compliance.’’

The hearing is planned to finish today.