Trial to transform beach muck

By Kiri Gillespie

A chance encounter between a woman with innovative green thumbs and a man dealing with green sludge has led to a major trial exploring different disposal options for sea lettuce.

The green invasion of slimy sea lettuce is an annual event on local shores each summer and can cost the Bay of Plenty Regional Council and Tauranga City Council up to $67,000 in disposal costs each year.

Now, Tauranga Harbour programme co-ordinator Bruce Gardner will head a trial exploring the use of sea lettuce as mulch for orchards, gardens, stock feed and possibly bio-fuel.

"The idea came from me, just by chance bumping into a lady collecting it in Kulim Park. She just swore by it. She thought it was a wonderful thing,'' Mr Gardner said.

"I thought it would be really good to have the science to see whether her perception was actually correct, that it was that beneficial to the soil.''

Traditionally, the lettuce was collected and disposed of at a compost facility at Te Maunga.

However, the spread of Psa through the region's kiwifruit vines meant there was little room left for sea lettuce.

The problem sparked Mr Gardner's idea for sustainable disposable options.

The project, which will run over the course of summer and autumn, will also explore the use of lettuce as stock feed, dewatering and turning it into pellets for fertiliser or using it for bio-fuel products.

"Rather than having all our eggs in one basket, we want to have a range of options available and people can use these.''

Mr Gardner said the lettuce was a nuisance and killed any sea life living on the foreshore if it was not removed in time.

When sea lettuce rotted, it released hydrogen sulphide _ the same gas and smell associated with Rotorua.

"If you live down Harbour Drive or that area in and the wind's blowing in shore, then sea lettuce there is quite a problem,'' Mr Gardner said.

The project will be helped under the regional council's Bright Ideas Innovation Fund, designed to assist innovative staff projects and ideas with $30,000.

Another project being explored at the regional council is the use of dairy farm effluent to fatten fish for commercial production or replenish native fish stocks.

Regional council corporate general manager Brian Trott said the Bright Ideas fund provided a boost to give staff time and some funding to get their ideas off the ground, and to hopefully benefit the region's communities as well.

"We've been excited to see the variety of projects staff have thought of_they're often the kind of things academic researchers might never come up with . . .'' Mr Trott said.

- Bay of Plenty Times

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