---
kind: "section"
citation: "40 C.F.R. § 503.46"
title: "40"
number: "503.46"
heading: "Frequency of monitoring."
url: "https://uscodex.org/cfr/40/503.46"
---

# §503.46. Frequency of monitoring.

- (a) **Sewage sludge.**
  - (1) The frequency of monitoring for beryllium shall be as required in [subpart C](/cfr/40/subpartC.md) of [40 CFR part 61](/cfr/40/part61.md), and for mercury as required in [subpart E](/cfr/40/subpartE.md) of [40 CFR part 61](/cfr/40/part61.md).
  - (2) The frequency of monitoring for arsenic, cadmium, chromium, lead, and nickel in sewage sludge fed to a sewage sludge incinerator shall be the frequency in Table 1 of § 503.46.
  - (3) After the sewage sludge has been monitored for two years at the frequency in Table 1 of § 503.46, the permitting authority may reduce the frequency of monitoring for arsenic, cadmium, chromium, lead, and nickel.
- (b) **Total hydrocarbons, oxygen concentration, information to determine moisture content, and combustion temperatures.** The total hydrocarbons concentration and oxygen concentration in the exit gas from a sewage sludge incinerator stack, the information used to measure moisture content in the exit gas, and the combustion temperatures for the sewage sludge incinerator shall be monitored continuously.
- (c) **Air pollution control device operating parameters.** For sewage sludge incinerators subject to the requirements in [subpart O](/cfr/40/subpartO.md) of [40 CFR part 60](/cfr/40/part60.md), the frequency of monitoring for the appropriate air pollution control device operating parameters shall be the frequency of monitoring in [subpart O](/cfr/40/subpartO.md) of [40 CFR part 60](/cfr/40/part60.md). For all other sewage sludge incinerators, the appropriate air pollution control device operating parameters shall be at least daily.

## Notes

### Amendments

[58 FR 9387, Feb. 19, 1993, as amended at 64 FR 42573, Aug. 4, 1999]

### Authority

Authority: Sections 405 (d) and (e) of the Clean Water Act, as amended by Pub. L. 95-217, sec. 54(d), 91 Stat. 1591 (33 U.S.C. 1345 (d) and (e)); and Pub. L. 100-4, title IV, sec. 406 (a), (b), 101 Stat., 71, 72 (33 U.S.C. 1251 et seq. ).

### Source

Source: 58 FR 9387, Feb. 19, 1993, unless otherwise noted.

### Amendments

[58 FR 9387, Feb. 19, 1993, as amended at 64 FR 42573, Aug. 4, 1999]