Fermentation installations for biological sewage purification; installations for the treatment, handling, transport, storage, mixing, filtration, purification, recycling and disposal of water, sewage, wastewater, sludge, slurry and odour; installations for the control of water pollution; water purification machines and apparatus; industrial wastewater purification plants; odour control apparatus; equipment and installations for treatment, handling, transport, storage, mixing, filtration, purification, recycling and disposal of water, sewage, wastewater, sludge, slurry and odour; installations for wastewater engineering; installations for the treatment of drinking water; desalination apparatus, equipment and installations; water, sewage, wastewater, sludge, slurry and odour distribution installations; aeration apparatus, equipment and systems for use in water, sewage, wastewater, sludge, slurry and odour treatment, handling, transport, storage, mixing, filtration, purification, recycling and disposal applications; coarse bubble, fine bubble and ultra-fine bubble diffusers, diffuser accessories, ejectors, parts, connections, fittings, piping and control systems for water, sewage, wastewater, sludge, slurry and odour treatment, handling, transport, storage, mixing, filtration, purification, recycling and disposal in channels, pipes, network systems, storage tanks, mixing tanks, aeration tanks, dams, rivers, ponds and lagoons; water, sewage, wastewater, sludge, slurry and odour treatment, handling, transport, storage, mixing, filtration, purification, recycling and disposal installations; machines, including mechanical aeration machines, diffused aeration machines and disinfection machines, for use in water, sewage, wastewater, sludge, slurry and odour treatment, handling, transport, storage, mixing, filtration, purification, recycling and disposal