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US3402817A
|
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Ballast operated filter
|
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|
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Filter bottom for fixed bed filters
|
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|
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Seal for filter bed cleaners
|
|
GB514982A
|
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Improvements connected with sand filter cleaning mechanism
|
|
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|
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Hydraulic and air washing of sand filters
|
|
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|
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Sealing plate for sand filter cleaners
|
|
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|
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Seal for sand filter cleaning mechanism
|
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Magnetic sewage clarification
|
|
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Ferric chloride feeder
|
|
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|
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Filter bed cleaning device for sewage clarification tanks
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|
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Method for treating sewage
|
|
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Apparatus for and method of treating sewage
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Apparatus and system for treating sewage
|
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|
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Apparatus for the clarification of sewage liquid
|
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|
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Method and apparatus for treating sewage
|
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Apparatus for cleaning sedimentation tanks
|
|
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|
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Filter bed cleaning device for sewage clarification tanks
|
|
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|
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Sewage clarification tank and cleaning machine therefor
|
|
US1919565A
|
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Means for cleaning sewage filter beds
|
|
US1919564A
|
|
Means for cleaning sewage filter beds
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