New uses for sea lettuce

A local man's ideas to turn sea lettuce into stock food, or turned into pellets for fertiliser, has earned him top honours in a competition aimed to encourage innovative projects.

Regional Council Tauranga Harbour programme co-ordinator Bruce Gardner is the winner of the council's Bright Ideas Innovation Fund, established in 2010 to help fund innovative staff projects and ideas.

The $30,000 fund is available for staff ideas that are likely to improve the value of the Regional Council's work in the community, but which fall outside standard work programmes.

Mr Gardner is looking into the viability of using sea lettuce for stock food, dewatering and turning it into pellets for fertiliser or using it for useful products such as bio-gas, bio-diesel or ethanol.

Most sea lettuce collected in the last two years has gone to Tauranga's Te Maunga compost facility, but now that Psa disease has resulted in a significant drop-off in demand from kiwifruit orchards, the facility is unable to take the lettuce any more.

Unless new uses are found, unsustainable disposal to landfill would cost the Regional Council and Tauranga City Council up to $67,000 in a bad sea lettuce year.

Mr Gardner's project includes trialling and monitoring using sea lettuce as fertiliser and promoting it to farmers, orchardists and gardeners, as well as investigating other options such as turning it into pellets for stock feed, biodigesting and fertiliser.

Earlier Bright Ideas projects are beginning to show success.

Council's Environmental Scientist Shane Iremonger's project to establish an odour threshold for hydrogen sulphide (Rotorua's smell) is determining how high levels have to be before people can detect them _  a vital factor for geothermal projects as well as wastewater treatment plants, waste transfer stations and composting operations.

No work has been done in New Zealand on this type of odour detection and local assessments have previously been based on international measures rather than local conditions.

Another project, proposed by Rivers and Drainage manager Bruce Crabbe, has investigated using dairy farm effluent to feed fish species for commercial production, or replenish native fish stocks.

A season of converting effluent to an edible food source has been completed in tank trials, and whitebait have been successfully fattened on dairy effluent.

On-farm trials are planned this year.

Regional Council Corporate General Manager Brian Trott said the projects staff have come up under the Bright Ideas scheme with have been exciting and innovative.

He said the Bright Ideas Innovation Fund provided "a bit of a boost'' to give staff the time and some funding to get their ideas off the ground, and benefit the region's communities.