Wet mass, total and volatile solids, COD and biodegradability
Biogas · anaerobic digestion
How to model anaerobic digestion and a biogas plant
Turn substrate assays and loading policy into gas production, digester capacity, heat demand, digestate flow and project economics.
Feed receptionBlendingDigestionGas storageCHP / upgradingDigestateExport
Engineering brief
Model the complete decision, not an isolated unit operation.
A biogas model must preserve feed variability and time. Acatian can connect volatile-solids loading, degradation, inhibition and hydraulic residence time to daily gas production and downstream capacity.
The complete plant boundary includes reception, storage, pasteurization where applicable, mixing, heating, gas handling, flare, CHP or biomethane upgrading, digestate treatment and parasitic loads.
01 · Model basis
What the Acatian model needs to resolve
Inputs, mechanisms, limits and outputs remain reviewable on one declared basis.Inputs
Feed cadence, blend limits and storage inventory
Methane potential, degradation rates and inhibition evidence
Digester volume, temperature, mixing, gas and digestate equipment
Mechanisms
Substrate and COD/VS balances
First-order or calibrated digestion kinetics
Gas composition, storage and conversion
Inventory, heat and electrical balances
Constraints
Organic loading and hydraulic residence time
Ammonia, VFA, pH and trace-element limits
Gas storage, flare and upgrader throughput
Feed seasonality and digestate outlets
Outputs
Methane production and uncertainty
Required active digester volume
Net electricity, heat or biomethane output
Digestate, emissions, cost and availability scenarios
02 · Acatian workflow
Build it in six controlled steps
Each step creates a reviewable object, not a hidden spreadsheet assumption.- 01
Create a traceable assay for every feedstock.
- 02
Define blending, storage and feeding events.
- 03
Calibrate conversion and gas composition.
- 04
Size digester, gas and digestate operations.
- 05
Overlay availability and seasonal inventory.
- 06
Compare energy, economic and environmental cases.
03 · Decisions
Questions the model should answer
Which feed blend is stable and valuable?
Does gas storage decouple production and demand?
CHP or upgrading: which fits the local boundary?
How much feed variability can the design absorb?
04 · Evidence boundary
Validate before the result carries weight
Validation
Validate gas yield, methane fraction, residual solids, heat demand and dynamic response against independent operating periods, not only BMP tests.
Limitations
The model does not replace biological safety review, gas-area classification, pressure protection, digestate regulation or emissions permits.
Frequently asked questions
Practical modelling questions
Can multiple wastes be blended?
Yes. Each feed can carry its own composition, availability, price and uncertainty before blending constraints are applied.
Can Acatian model biomethane upgrading?
Yes. Recovery, methane slip, electricity, consumables and product specification can be represented.
Can seasonal feed supply be scheduled?
Yes. Inventory and feed events can be evaluated against digester and gas-handling capacity.