Sludge Watch ==> New Zealand - sewage sludge compost site closes due to odors, cost, no market

[Maureen Reilly]

Sludgewatch Admin:

There it is:
A sludge compost site cost the public $17M to build
And they got
1. high costs
2. high stink
3. no market for the finished material.

Take heed...this is not the way to go with sludge.
This story is the same everywhere.

For instance:
in Canada ...Ottawa sewage sludge is sent into Quebec. It is still sitting 
there years later at the 'compost' site..."Mount Ottawa".  It should be 
tourist destination.


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Carey’s Gully Composting Operation To Change
Friday, 7 December 2007

Press Release: Wellington City Council
New Zealand


Change is afoot at Wellington City Council’s composting facility at Carey’s 
Gully (the Southern Landfill). The Council has announced it is to 
discontinue the conversion of sewage sludge into compost at the site.

The Council has decided to halt the existing composting operation when its 
contract with the facility operator - Living Earth Ltd – terminates at the 
end of 2008. The principal reasons for the closure are:



Increasing costs associated with running the plant

The lack of a viable market for the compost

Difficulties in eliminating the smells

The advent of new alternative and sustainable ways of dealing with the 
sludge.
Smells periodically generated by the sludge processing operations have been 
at the centre of continuing complaints from residents in Brooklyn and nearby 
southern suburbs.

Councillor Celia Wade-Brown, the Council’s Environment Portfolio Leader, 
says the Council is looking at a number of alternatives to composting the 
sludge. This includes a possible regional joint-venture with Porirua City – 
in which the sludge from both cities could be artificially dried to greatly 
reduce its volume and then used to generate gas which, in turn, can generate 
electricity.

She says the news will likely be welcomed by residents neighbouring Carey’s 
Gully.

“We are acutely aware that the compost plant and associated infrastructure, 
including the sewage sludge dewatering plant, have been sources of odour 
since they opened almost 10 years ago.

“We have worked with Living Earth and other operators for a number of years 
in a bid to reduce the smells – however it has not been possible to 
adequately reduce odour and we know this has not been to the satisfaction of 
our neighbours.”

The composting plant, which cost $17 million to build, has processed some 
130,000 tonnes of dewatered sewage sludge from the Moa Point and Western 
(South Karori) treatment plants and has produced some 25,000 cubic metres of 
compost a year.

Cr Wade-Brown says that prior to the construction of the Moa Point and 
Western treatment plants, “all of that sludge would have ended up in Cook 
Strait. The removal of this vast amount of human pollution has transformed 
Wellington Harbour and the South Coast – for the better.

“It’s disappointing the sludge-composting operation has not been the success 
it was hoped to be when first mooted as part of the then-leading edge 
Clearwater sewage treatment scheme in the mid-1990s.

“However technology and waste-disposal thinking has progressed considerably 
– even in the past decade. There are new, more environmentally sustainable 
means of disposing of the sewage sludge and we have already started work to 
look at the best option for Wellington City.”

Mike Mendonca, Manager of Wellington City Council’s CitiOperations unit 
which runs the Southern Landfill, says the Council still intends to run a 
composting operation at the Southern Landfill – this will deal with the 3000 
tonnes of green waste brought to the landfill each year, along with the 
increasing amounts of food waste from Wellington restaurants and other food 
premises being collected as part of the ‘Kai to Compost’ scheme.

And Mr Mendonca says the Council will actively investigate options to 
encourage more green waste and food-waste recycling. He says an enormous 
amount of garden waste, vegetable cuttings and other food scraps go into the 
landfill at the moment. “If we can reduce that waste stream then we’ll 
extend the life of the landfill and still be able to produce top-quality 
compost.

“This will also address the issue of methane production from the landfill. 
The less green waste that is composted instead of landfilled, the less 
methane is produced.”

The City Council will immediately start discussions with Living Earth 
Limited about the transition away from processing sludge through the 
composting plant.

Mr Mendonca says nearby residents can expect the odour situation to improve 
over the next year.

http://www.scoop.co.nz/stories/AK0712/S00069.htm