Quick answer: monitor H2S, methane (%LEL) and O2 at wet wells, pump stations, headworks and digesters; Cl2 and NH3 at chemical storage and dosing rooms; and use distributed nodes for remote lift stations and collection-system assets.
The gas hazards
- Hydrogen sulfide - NIOSH IDLH 100 ppm.
- Methane - from anaerobic digestion; LEL 5% by volume.
- Chlorine - common disinfectant; OSHA ceiling 1 ppm.
- Ammonia - from industrial discharge.
- Oxygen depletion - below 19.5% is oxygen-deficient under OSHA.
- Carbon dioxide - biological treatment byproduct.
Where fixed detection fits
- Pump stations and wet wells
- Anaerobic digesters and biogas facilities
- Chemical storage and dosing areas
- Sludge processing
- Confined spaces
Where wireless fits
- Remote and hard-to-reach locations
- Temporary maintenance and repairs
- Emergency response
- Perimeter monitoring
Regulations to know
OSHA Permit-Required Confined Spaces (29 CFR 1910.146).
Safeguard products that apply
- SA-220 Fixed Gas Detector - single sensor, 4-20 mA and Modbus output, optional relays, rated -40 °C to +60 °C. Hazardous-location certification is in progress and not yet held.
- SA-XDS (diffusion) and SA-XES (aspirated) multi-sensor gas detection systems.
- SCX Gas Detection Control System.
- Foresight - remote visibility suited to unmanned lift stations.
Exposure limits cited are from OSHA and NIOSH. Confirm detector selection and placement against your site's hazard assessment, and verify specifications with Safeguard before specifying equipment.