Anaerobic Digestion Process Safety

1
Anaerobic Digestion Process Safety

• Presented by IWEA Safety Committee in conjunction
  with IWEA Operations and Maintenance Committee

2
Introduction

• Safety First
• Digesters and their related equipment include
  many hazardous areas and potential dangers
• Thoroughness and an understanding of the inherent
  dangers present is needed when working around or
  in a digester space

3
Put The Pieces Together

• All of your training and experience is necessary
  when working around anaerobic digesters

P.M.
O M
Training
PPE
MSDS
Lotto
Confined Space
Proper Tools
Inspect
4
Gas System Dont Play With Dynamite

• The anaerobic digestion process produces 8 to 12
  cubic feet of gas for every pound of volatile
  matter added, and from 12 to 18 cubic feet of gas
  for every pound of volatile matter destroyed.
  The gas contains mainly methane and carbon
  dioxide. The methane content in a properly
  functioning digester may vary from 65 to 70,
  with carbon dioxide running about 30 to 35 by
  volume.

5
Gas Equipment

• The pressure relief valve
• The vacuum relief valve
• The flame arrestor
• Between vacuum and pressure relief valve and the
  digester dome
• After sedimentation traps
• At waste gas burner
• Before every boiler, furnace, or flame
• Thermal valves

6
Miscellaneous Safety

• Guardrails need to be installed along the edges
  of the digester roof or cover in areas where it
  is necessary to work close to the edge, with toe
  boards.
• Boilers must be inspected every year and the
  certification must be posted in that area.
• All mechanical equipment (including lighting and
  sump pumps) must be explosion proof
• No smoking signs surrounding the digesters
  including pipe chases

7
Where to Get More Information

• IWEA Safety Committee
• Kathy Dillion at 317-852-1114 or
  kdillion_at_brownsburgwwtp.org
• WEF Books, Journals, On-line
• Buset
• OSHA