|
US2352624A
|
|
Filter bed cleaning
|
|
US2222651A
|
|
Fermentation cell for converting organic matter to humus
|
|
US2118208A
|
|
Incineration
|
|
US2115337A
|
|
Incineration
|
|
US2136451A
|
|
Incineration
|
|
US2114566A
|
|
Incineration
|
|
US2145090A
|
|
Incineration
|
|
US2150231A
|
|
Incineration
|
|
US2117487A
|
|
Incineration
|
|
US2181190A
|
|
Apparatus for treating material
|
|
US2086821A
|
|
Screen cleaning
|
|
US2077907A
|
|
Means for treating sewage, industrial wastes, and the like
|
|
US2084659A
|
|
Treatment of sewage, industrial waste, and the like
|
|
US2028949A
|
|
Filter
|
|
US2086829A
|
|
Combined settling and filtration
|
|
US2077498A
|
|
Disposal of sewage and the like
|
|
US2054395A
|
|
Apparatus for aerating sewage and the like
|
|
US2046845A
|
|
Treatment and disposal of sewage and the like
|
|
US1937481A
|
|
Sewage treatment and disposal
|
|
US1956411A
|
|
Apparatus for and method of treating liquids
|
