Stirrers; mechanical mixers [machines]; presses; pumps [machines]; hydraulic pumps; recycling pumps; transfer pumps for biogas plants; pump diaphragms; valves [parts of machines]; gates [parts of machines]; mud catchers and collectors [machines]; solid-liquid separation apparatus for the treatment of fluid-containing waste; sludge composting apparatus; waste dewatering composting apparatus; electric motors for machines; aerators [machines].