C
SECTION C — CHEMISTRY AND METALLURGY
  
CHEMISTRY
 C02
TREATMENT WATER, WASTE WATER AND SEWAGE (distilling, filtering, separating B01)
 C02B
TREATMENT OF WATER, e.g. PURIFICATION (adding materials to water to prevent corrosion of metals C23F)

 C02C
TREATMENT OF SEWAGE AND WASTE WATER (C02B takes precedence)

 C02D
WATER IMPREGNATED WITH CARBON DIOXIDE OR OTHER GASES