Technical assessment of methods for waste isolation on the abyssal seafloor

A study was recently completed to analyze methods for isolating industrial wastes (i.e., sewage sludge, fly ash from municipal incinerators, and dredged material) on the abyssal seafloor. This paper presents results of the technical assessment of this waste management option. The assessment identified three viable techniques: (a) a 25,000 metric ton displacement (loaded) unpowered submarine barge, (b) a 5,000 metric ton displacement (loaded) disk-shaped transporter traversing to and from the seafloor much like an untethered elevator, or (c) free falling the waste from the ocean surface in 400 m³ synthetic fabric containers carrying waste-filled containers to the seafloor. Risk analyses show that the free-fall fabric container poses the least technical risk, provided that fabric container and transporter designs eliminate the potential for tearing of the containers on release from the surface transporter. All three techniques are shown to offer cost effective waste management options when compared with present-day waste disposal practices