Anaerobic Digestion

What you will learn

Taught by Brad Musick. 10 modules. Examples come from the White River Resource Recovery Facility (WRRRF), a fictional training plant.

1. The four stages and two populations (25 min)The anaerobic pathway from sludge to methane, and how digesters sour.
2. Environmental requirements and pH buffering (20 min)Why pH is a late warning, how bicarbonate alkalinity, volatile acids and gas-phase CO2 control pH, and how to read the VA/ALK ratio.
3. Biogas quality and digester gas safety (20 min)Methane, carbon dioxide, hydrogen sulfide and oxygen in biogas, plus temperature, mixing and inhibition.
4. Commissioning a new digester: checks, filling and heating (20 min)Pre-commissioning checks, filling, and a worked example of heating the fill.
5. Nitrogen purging (20 min)Why we purge with nitrogen, the purge procedure, dilution purge math, a worked example, and nitrogen safety.
6. Seeding and feed ramp-up (15 min)Seeding the new digester, ramping up the feed, and deciding when the gas is good enough.
7. Applied digester math (35 min)Sludge pounds, feed solids and volatile solids, VS loading and HRT, Van Kleeck volatile solids reduction, and gas production.
8. VA/ALK, alkalinity addition and decision math (25 min)Calculating alkalinity additions, and decisions such as how much FOG a digester can take and whether gas is going missing.
9. The daily digester routine (20 min)What to check, what to adjust, by how much, and how long to wait, including boiler and heat exchanger temperatures, gas meter flows, condensate traps and the flare pilot.
10. Systematic troubleshooting and exercises (25 min)Guides for rising VA/ALK and souring, falling temperature, mixing loss with scum and grit, and oxygen in biogas or cover pressure. Exercises: a FOG slug, a boiler trip, ramp-up and lost volume. Foam, cover and relief valve safety, and using trend data as an early warning of souring, with the operator making the decision.

See how it works