'Slop Chute': How the USS Abraham Lincoln legally dumps its trash at sea
The USS Abraham Lincoln uses a 'slop chute' to legally discharge pulped biodegradable waste. Following MARPOL rules, the Navy shreds food while storing all plastics for land disposal to protect the oceans.
Floating city waste
The USS Abraham Lincoln houses over 5,000 sailors who generate tonnes of waste daily. Managing this requires a massive industrial operation to keep the ship functional and sanitary during long deployments.
The 'slop chute' system
The 'slop chute' is the final exit point for biodegradable waste processed on board. Before reaching the chute, food and paper are turned into a slurry to ensure they dissolve quickly in seawater.
Strict 3-mile limit
The Navy follows international MARPOL standards for sea disposal. Pulped food and paper waste can only be legally discharged when the aircraft carrier is at least 3 nautical miles away from the nearest land.
Pulpers and shredders
Waste is not simply thrown overboard in its original form. Massive machines called pulpers shred paper and food into tiny pieces that can pass through a 25 mm screen before discharge.
12-mile refuse rule
Non-comminuted food waste and paper must be kept on board until the ship is 12 nautical miles from land. This ensures that any solids discharged are far enough offshore to be naturally dispersed by ocean currents.
Zero plastic discharge
Current laws strictly prohibit the US Navy from dumping any plastic into the ocean. All plastic waste is shredded, compressed, and melted into solid plastic disks that are stored for later landfill disposal or recycling.
Metal and glass
Shredders are used to crush and cut metal and glass into small pieces. These materials are then placed into weighted burlap bags designed to sink directly to the bottom of the sea.
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