StacksVerified U.S. regulatory reference

40 CFR §421.336

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
Except as provided in 40 CFR 403.7, any new source subject to this subpart which introduces pollutants into a publicly owned treatment works must comply with 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass of wastewater pollutants in primary zirconium and hafnium process wastewater introduced into a POTW shall not exceed the following values:
  1. (a)Sand drying wet air pollution control.
  2. (b)Sand chlorination off-gas wet air pollution control.
  3. (c)Sand chlorination area vent wet air pollution control.
  4. (d)SiCl4 purification wet air pollution control.
  5. (e)Feed makeup wet air pollution control.
  6. (f)Iron extraction (MIBK) steam stripper bottoms.
  7. (g)Zirconium filtrate.
  8. (h)Hafnium filtrate.
  9. (i)Calcining caustic wet air pollution control.
  10. (j)Pure chlorination wet air pollution control.
  11. (k)Reduction area-vent wet air pollution control.
  12. (l)Magnesium recovery off-gas wet air pollution control.
  13. (m)Magnesium recovery area-vent wet air pollution control.
  14. (n)Zirconium chip crushing wet air pollution control.
  15. (o)Acid leachate from zirconium metal production.
  16. (p)Acid leachate from zirconium alloy production.
  17. (q)Leaching rinse water from zirconium metal production.
  18. (r)Leaching rinse water from zirconium alloy production.