Feedstock science · GERMI

Measured before promised.

Before a feedstock earns digester volume in our designs, it goes to the laboratory. Our biochemical methane potential work was carried out with GERMI — the Gujarat Energy Research and Management Institute. This page describes what was tested and how; the numbers travel with the project documents they belong to.

01
What a BMP is

The sector's honest yardstick.

A biochemical methane potential study answers one question under laboratory control: how much methane can this specific material yield when digestion is given every chance to finish? It is the standard way the sector tests a substrate before committing digester volume, capital and a catchment's trust to it.

Modelled figures can be argued with. A BMP curve, run with controls, is simply what the material did.

02
What was tested

The four streams the design is built around.

Samples spanned the feedstock families our plants are designed for: sugar-industry press mud, cattle dung, crop residue and organic market waste — individually and with an eye to the seasonal blends the Sangola research plant will run.

Characterising each stream separately is what lets a multifeed plant change its recipe with the seasons without changing its gas quality.

03
How the assays were run

The criteria behind the study.

A
Substrate characterisation first

Each sample profiled before any digestion: total solids, volatile solids, pH and carbon-to-nitrogen ratio — so yield is read against what the material actually is, not what it is assumed to be.

B
Controlled batch digestion

Sealed batch assays under controlled mesophilic temperature, with a defined inoculum-to-substrate ratio — the standard conditions that make one feedstock's result comparable with another's.

C
Controls and replicates

Blank controls to subtract the inoculum's own gas, reference substrate to confirm the culture is healthy, and replicate assays so a single odd bottle cannot write the answer.

D
Yield tracked to plateau

Cumulative methane recorded until the curve flattens — the full potential of the material, not a snapshot partway through digestion.

04
What the results are for

Numbers that work for a living.

The quantified yields from this work are not decoration — they set co-digestion ratios, size digester volume against real intake, and anchor the yield assumptions in our detailed project reports, including the DPR evaluated at IIT (BHU) Varanasi and SSS NIBE Kapurthala.

In line with how every figure on this site is treated, the quantified results are carried in project documentation and re-derived for each project's own feedstock — a number measured for one catchment is a starting point for the next, never a promise.

Feedstock questions? Bring a sample.

If you are weighing a residue stream for a plant, the honest first step is the same one we took.

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