by Ashley Miznazi / © 2024, Miami Herald. Distributed by Tribune Content Agency, LLC.

Seaweed poses all sorts of problems when it piles up on South Florida beaches. It stinks, spoils the view and is pricey to haul off to the landfill, which currently is the only viable disposal option.

  Someday maybe a ton of sargassum might be worth its weight in, if not gold, maybe fertilizer. Turning seaweed into plant food is one of six proposals that Miami-Dade is considering as part of a county effort to find new ways to deal with a seaweed surge that scientists expect climate change will only make worse.

  These ideas spring from an invitation for fresh approaches offered last year by the Miami-Dade Innovation Authority, a nonprofit that connects local government to private technology companies. The agency has now selected six finalists to come up with environmentally friendly ways to get rid of all the seaweed that annually piles up on South Florida’s shores. At least three winners will each get $100,000 to take on a challenge complicated by the fact that sargassum often contains unhealthy levels of heavy metals and arsenic.

  Here’s a look at the proposals.

Creating ‘green hydrogen’

  Chemergy was incorporated in Miami in 2011 by a family with a dream of producing low-cost renewable “green hydrogen” fuel from organic and plastic waste. Maybe sargassum could be part of that waste stream, too.

  The system uses a chemical process that takes organic material and burns and separates it into hydrogen, carbon dioxide and ash. The CO2 is sequestered and the hydrogen can be stored to, one day, be put into the grid or be used for transportation.

Helping plants grow

  EcoChar, a company based in the Netherlands, applied to burn the sargassum into an agricultural product called biochar. Biochar contains mineral ash, phosphorus, potassium, magnesium and fixed carbon that can be used as a soil additive that increases water retention.

  Shane McGolden, the U.S.-based EcoChar spokesperson, said when organic material is burned into char, the heavy metals are locked and stored.

  The equipment, however, is not portable and goes for millions.

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