DECIMAL CLASSIFICATION 
628.20 
27 
.28 
.29 
3 
21 
32 
33 
34 
341 
342 
343 
344 
345 
346 
347 
348 
349 
35 
36 
361 
362 
363 
364 
365 
366 
367 
368 
369 
¥i 
38 
30 
4 
41 
42 
43 
a4 
45 
46 
47 
48 
409 
River crossings 
Intercepting and outfall sewers 
Reservoirs and tank sewers 
Pumping stations 
Sewage and its disposal 
Physical properties of sewage 
Deodorization and disinfection of solids and liquids 
See also 628.237 
Subsidence 
Precipitation 
Precipitation tanks 
Mixing machinery 
Filter presses 
Precipitation by salts of alumina 
By lime 
By salts of iron 
By other methods 
Disposal of sludge 
Miscellaneous 
Biltration 
lrrigation 
Broad irrigation 
Ridge and furrow irrigation 
Flatbed irrigation 
Subsurface irrigation 
Intermittent downward filtration 
Carriers and appurtenances 
Drains and drainage of sewage farms 
Filtration areas 
Miscellaneous 
Sewage farming 
methods 
Sewage manures See also agriculture, 631.8425 
Discharge into sea, etc. 
Sanitation of towns 
Middens and privies 
Pail systems 
Earth closet systems 
Domestic ashes, garbage and refuse 
Public urinals and latrines 
Street cleaning and sprinkling 
Pavements and subways 
Trees in streets and squares 
Manufacture of fertilizers from town wastes 
Required modifications of ordinary