Volume biodigestor (m³)
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
About this calculator
This calculator determines the required useful volume of a biodigester based on daily organic waste load and hydraulic retention time (HRT). A biodigester treats organic waste such as manure, food scraps, or agro-industrial effluents in an anaerobic environment, producing biogas and biofertilizer. Volume is the most critical design factor: undersizing causes process failure due to insufficient contact time; oversizing increases costs without benefit.
The calculation uses the formula V = load × HRT, where 'load' is the daily amount of waste to be treated, typically expressed in cubic meters per day (m³/day) or kilograms per day converted by density, and 'HRT' is the time in days that the waste stays inside the biodigester for anaerobic digestion. For example, for 2 m³/day of manure with an HRT of 30 days, the required volume is 60 m³. HRT depends on operating temperature: in warm climates it can be shorter (20 to 30 days); in cold climates, longer (40 to 60 days).
This tool is useful for farmers, livestock producers, waste managers, and engineers designing biogas systems. Common cases include sizing biodigesters for pig, cattle, or poultry farms, processing dairy effluents, and restaurant waste. Before using, remember that the load should consider the total volume of liquid waste, not just the solid part; dilution water also counts.
Key precautions: waste density varies and affects actual volume; for instance, 1 ton of manure can occupy more than 1 m³. Recommended HRT must be adjusted according to local average temperature and biodigester type (Indian, Chinese, tubular models). Consult a specialist to validate parameters, as microbial activity is sensitive to pH and nutrients. The calculator provides an initial estimate, not a detailed design.
Frequently asked questions
What is HRT and how to set the ideal value?
HRT stands for Hydraulic Retention Time, the number of days waste stays in the biodigester. The ideal value depends on temperature: in warm regions use 20 to 30 days; in cold regions, 40 to 60 days. Consult a technician for your case.
How do I measure the daily waste load?
The load should be the total volume of liquid waste added per day. If using manure, measure in m³ or kg and convert by density (1 m³ ≈ 1 ton for water, but manure may be lighter). Include dilution water.
Is this volume sufficient for biogas production?
Yes, the calculated volume ensures the necessary space for treatment, but biogas production depends on organic load and HRT. This calculator focuses on reactor sizing, not gas estimation.
Can I use it for solid waste like food scraps?
Yes, as long as you convert the load to liquid volume. Food scraps need to be ground and diluted into a pumpable slurry. Use approximate density to convert mass to volume.
How is this different for batch biodigesters?
This calculation is for continuous biodigesters where waste is added daily. For batch type, volume is determined by the total waste per batch, and HRT does not apply the same way.