---
kind: "section"
citation: "40 C.F.R. § 434.64"
title: "40"
number: "434.64"
heading: "Procedure and method detection limit for measurement of settleable solids."
url: "https://uscodex.org/cfr/40/434.64"
---

# §434.64. Procedure and method detection limit for measurement of settleable solids.


For the purposes of this part, the following procedure shall be used to determine settleable solids: Fill an Imhoff cone to the one-liter mark with a thoroughly mixed sample. Allow to settle undisturbed for 45 minutes. Gently stir along the inside surface of the cone with a stirring rod. Allow to settle undisturbed for 15 minutes longer. Record the volume of settled material in the cone as milliliters per liter. Where a separation of settleable and floating materials occurs, do not include the floating material in the reading. Notwithstanding any provision of [40 CFR part 136](/cfr/40/part136.md), the method detection limit for measuring settleable solids under this part shall be 0.4 ml/l.


## Notes

### Authority

Authority: 33 U.S.C. 1311 1314(b), (c), (e), and (g), 1316(b) and (c), 1317(b) and (c), and 1361.

### Source

Source: 50 FR 41305, Oct. 9, 1985, unless otherwise noted.