Family turns mussel waste into farming products

The Brownlee family from Havelock, the Greenshell Mussel Capital of the World, is not only reducing waste, but helping farmers throughout New Zealand with their mussel shell products.

Havelock Shell Processors, owned by Michael Brownlee and his family, have been using mussel shell waste on their farm for decades, originally as fertiliser and grit for chickens, before setting up the business and diversifying into landscaping, composting, filtration socks, spill absorption, horse arenas and cow lanes among other things.

“It’s always good to do your bit for the environment, so being able to take a waste product and produce something beneficial that is also fully natural is great,” Michael says.

Initially, Michael’s grandfather (Bill Brownlee Senior) agreed to have scallop shells dumped on their farm in the 1960s.

That progressed to mussel shells in the 1970s when Michael’s dad (also Bill Brownlee) took over the farm. It wasn’t until two decades later that the Brownlee family started utilising the mussel shell properties of 91% calcium carbonate (lime) and traces of nitrogen, boron, magnesium and other minerals.

“In the 1990s, dad initially got a couple of truckloads of the scallop shells crushed which was used as lime on his farm,” Michael explains.

“A number of years later, after a couple of conversations and having some lab testing done, we discovered we had a pretty amazing product.”

“Dad bought a crusher in 2010 and set about modifying it to crush the shells for fertiliser for supply.”

Michael now runs the 150ha dry stock and cropping farm, including Havelock Shell Processors, a crushing plant used to turn the 13-metre-high pile of Greenshell mussel shells from the Sanford factory into products.

“The shell lime is predominantly supplied to farmers in the Top of the South, but we do have commercial vegetable growers in the North Island who use it,” Michael says.

Interestingly, while Havelock Shell Processors’ customers are predominantly farmers who use the lime-rich shells instead of quarried lime, their other products are also being used across different industries.

The semi-crushed shells have different uses, including for compost, landscaping for garden paths, mulch and decorative purposes, along with controlling grass grubs on vineyards.

Their products are also used in the mining and civil engineering industries for wastewater filtration and clean up, including by some councils after storm events.

“We have a portable version, this being our filtration socks which have many uses but are currently used mainly on building sites and roading projects,” Michael says.

Havelock Shell Processors are currently supplying shells to the Nelson branch of the University of Auckland for trials to reduce resuspended seabed sediment and to investigate its use as a cement binder for artificial reefs.

While a University of Canterbury research project used Greenshell mussel shells to filter zinc and copper running off Christchurch roofs, which has now become a company selling the Storminator™ Lite and the Storminator™ Barrel products to treat metal roof runoff.

“It’s interesting to be involved in the innovation and trialling of uses for the shells,” Michael says.

“As it stands, annually we keep thousands of tonnes of waste going to landfill and as the uses grow this will increase.”

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