Australia's Lord Howe Island may have road-tested a solution for organic wastes on our Gulf Islands. Like the Gulf Islands, all of Australia is challenged with water and soil shortages. They needed a solution that feeds the earth instead of the sky.
Lord Howe Island is an independent principality of Australia, with around 300 locals and 450 vistors at any one time. It is also a world heritage listed region.
Here's what they are doing with their organic wastes. They installed (with aid from other levels of government) a Vertical Composting Unit (VCU) that employs a gravity-feed system to process 0.8 to 1.2 tonnes of organics a day to produce 0.5 - 0.75 tonnes of compost that locals use in their gardens. The VCU can handle all "putrescibles" including sewage sludge.
The composting program is part of a "cost efficient waste minimisation strategy" proposed in a comprehensive study done in the late 1990s.