Columbia subject headings:
Chemical industry--Waste disposal--Handbooks, manuals, etc.
Sewage--Purification--Handbooks, manuals, etc.
Harvard subject headings:
Chemical industry--Waste disposal--Handbooks, manuals, etc.
Sewage--Purification--Handbooks, manuals, etc.
Princeton subject headings:
Chemical industry--Waste disposal--Handbooks, manuals, etc.
Sewage--Purification--Handbooks, manuals, etc.