Tom Stieghorst
Anyone who has a compost pile in the backyard to add mulch and fertilizer to their garden bed is familiar with the basic concept behind a technology being tested on Carnival Corp. ships to process food waste.
The biodigester being piloted by Carnival mixes food scraps with microbes and enzymes, breaking down leftover pizza, scrambled eggs, surf-and-turf, sole almandine and any of the thousand other food items found on cruise ship menus these days into a stream of liquid and solid disposable effluent.
Carnival says the main end-product is "a translucent, environmentally safe liquid." If it works as other food waste biodigesters do, the result is essentially liquid fertilizer.
"Think of a food waste biodigester as a large, stainless steel stomach that digests food waste: if you can feed it to people, you can feed it into a digester," said Chris Donald, senior vice president of corporate environmental compliance at Carnival Corp.
Carnival's application, currently being tested on seven of its nine brands, isn't without precedent. Restaurants, hotels, government facilities, stadiums, and theme parks are among the consumer users. Farmers have adopted them to make their agricultural footprint more environmentally friendly.
But Carnival claims that its prototypes are the first use of biodigesters at sea. They are currently being evaluated on 15 ships, with 12 more scheduled in coming months, including ships from Carnival Cruise Line, Costa Cruises, Cunard, Holland America Line, P&O Cruises (UK), Princess Cruises and Seabourn.
One immediate benefit is the saving of fuel and the resulting greenhouse gasses that result from incineration of food waste in current practices. Biodigesters have also been used to produce biogas, a potential fuel substitute for petroleum.
Another benefit is that the enzymes won't digest any plastics that accidentally slip into the waste stream, enabling them to be screened out before they unintentionally get discharged with other refuse.
Food waste biodigesters are placed in strategic areas, such as a ship's galley, enabling more convenient and efficient food waste processing at the source, Carnival said.
All of this seems rather esoteric for a travel advisor trying to match a client with the best cruise. But the cruise industry is on the receiving end of some environmental criticism these days, and understanding that the industry is coming up with innovative and scientific answers for these criticisms is a good thing for agents to know.