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Sewage treatment system
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Waste treatment package plant
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Venturi aerator and aerating process for waste treatment
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Ring-type gas dome for anaerobic digesters
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Liquid level control mechanism
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Sewage treatment system
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Multi-way indexing valve
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Gas scrubbing apparatus
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Gas diffusion apparatus
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Gas diffusing apparatus
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Treatment of sewage and other waste material
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Gas discharge device for sewage digestion tanks
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Method of and apparatus for digesting sludge
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Improvements in or relating to process for removing foreign materials from raw wool
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Method and apparatus for digesting garbage and sewage sludge
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Apparatus for heating materials
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Process for sewage treatment
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Supernatant selector device for sludge digestion tanks
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