# How much methane comes from a Salem sago unit's effluent lagoon, and does biogas capture help?

Canonical: https://senseible.earth/answers/salem-sago-unit-effluent-methane-biogas

Open anaerobic lagoons release methane from the effluent's organic load. The IPCC method is COD removed × 0.25 kg CH4 per kg COD × a correction factor, up to 0.8 for deep anaerobic lagoons. Covering the lagoon and burning the biogas turns most of that methane into CO2.

## Steps

1. Effluent volume and COD in and out, from lab tests.
2. COD removed in the lagoon, in kg.
3. CH4 = COD removed × 0.25 × the correction factor.
4. CO2e = CH4 × its GWP.

## Capture

Biogas used in a boiler can replace fuel too. Projects that capture and use it may earn carbon credits under approved methodologies.

## What Senseible does here

Senseible reads fuel invoices into a dated, fingerprinted record, so each figure shows the quantity, factor and document it came from.

- [Wastewater biogas carbon credits](https://senseible.earth/answers/food-factory-wastewater-biogas-carbon-credits)
- [Sago starch footprint](https://senseible.earth/answers/sago-starch-carbon-footprint-per-kg)
- [Biomass in a boiler](https://senseible.earth/answers/biomass-or-waste-fuel-in-boiler-scope-1)

Sources: [2006 IPCC Guidelines for National Greenhouse Gas Inventories](https://www.ipcc-nggip.iges.or.jp/public/2006gl/), [GHG Protocol Corporate Standard](https://ghgprotocol.org/corporate-standard)

Last reviewed 2026-10-22.