To ask the Secretary of State for Defence what (a) estimate he has made of the volume and (b) assessment he has made of the types of outputs that arise from treatment by pyrolysis of wastes from Royal Navy vessels at sea; how these outputs are treated; and if he will make a statement. (207512)

A development programme for installing pyrolysis systems on to Royal Navy vessels,to process food and general waste, including paper, cardboard, tin cans, and plastic, is currently under way. During a successful period of shore-based testing, waste volume reductions in excess of 85 per cent. and mass reductions of 50 per cent. have been achieved.

Starting later this year, the pyrolysis system will begin a 12-month sea trial onboard HMS Ocean and it is anticipated that the typical daily volume of general waste produced on the vessel could be reduced by up to half. If the sea trials are successful, there are plans to fit the system to the other vessels in the Fleet.

There are two by-products of the pyrolysis process, a solid residue and waste gas. The solid residue cannot be discharged into the sea under MARPOL regulations so it will be sealed in steel pails and stored on board the vessel until it can be removed to landfill sites. The gas produced is well within the requirement of MARPOL regulations and the on-board processing unit will further refine it to bring it well within the parameters of more stringent land-based regulations, before release.

To ask the Secretary of State for Defence what (a) assessment he has made of the types and (b) estimate he has made of the volume of residues from the treatment of wastes which were discharged at sea by Royal Navy vessels in each of the last five years. (207513)

Records of discharges of wastes from Royal Navy vessels are retained on board. The RN does not routinely collate or estimate the total volumes of waste streams which are discharged at sea. Wastes are discharged in accordance with IMO Marine Pollution regulations.