LLS claim that they will be able to remove up to 85% of the solid waste, but at the time of writing there is no data to show that the FiiZK Certus model of cage which they propose to use has been successful in achieving this, as none have yet been sold with waste extraction fitted.
The 85% figure that LLS quote is based on a computer model ("new DEPOMOD") which models the way particles travel down through a water column in order to predict the impact of fishfarm discharges on the environment.
LLS have used this model to estimate how fish faeces travel within the proposed semi-closed cages, even though the model does not take into account either the disturbance caused by the stocked fish or other factors impacting on solid waste collection within the semi-closed cages.
As far as we can ascertain, waste collection has never been carried out anywhere globally at inshore locations, and certainly not on the scale proposed, so there is also no live or operational data to corroborate their claims on waste removal. With no test data and questionable modelling, the assertion that this is ”proven technology” is without proof.
Even if their claims were true, the amount of waste from the proposed mega-farm which would enter the loch is enormous. Even assuming that 15-50% of the solid waste is captured - fish faeces and the inevitable loss of feed - all the urine will enter the loch without treatment. Our estimates are that this would lead to some 25.6 tonnes of nitrogen waste (pee) and between 252 to 840 tonnes of solid waste, all deposited into the loch at the same location. As much poo as the human population of Oban - the environmental impact can only be imagined.