ESG reporting: the gel line in a sustainability statement

A draft sustainability page landed on my desk with the line ‘100 percent of food waste diverted from landfill’ and a footnote that said ‘diverted to energy recovery’. Both statements were true. Together they were misleading, and a reviewer would have found that in about four minutes.

Solidified kitchen waste is awkward to report because it improves some numbers and worsens others. Getting the claim right is less about marketing and more about knowing which metric you can defend.

Pick the metric you can defend

There are four candidate metrics, and they measure different things. Tonnage diverted from landfill. Tonnage sent for recovery. Litres of free liquid kept out of the drainage system and the collection vehicle. And truck movements avoided through fewer collections.

Solidification helps most with the third and fourth, helps somewhat with the first, and does nothing for the second unless your haulier’s route actually recovers something. A statement that leads with litres and truck movements is defensible. One that leads with ‘zero waste’ is not.

The strongest single number for most kitchens is something like: ‘We removed an estimated 3,100 litres of free liquid per month from the waste stream, which reduced collections from five per week to three.’ That is specific, auditable and true, and it does not require anyone to certify a carbon factor.

Weight gain cuts both ways

Here is the part that sustainability teams find uncomfortable. Gelling adds water weight to the load. The water was always there; it used to run into a drain or a compactor sump, and now it leaves in the bin. If your headline metric is tonnes of waste, solidification makes it worse, sometimes by 8 to 12 percent.

That is not a reason to avoid it. It is a reason to report intensity rather than absolute tonnage: kilos per cover, or kilos per $1,000 of revenue. Intensity figures show the real picture, and they are the ones a serious reviewer prefers anyway.

If you report absolute tonnage and it rises after a solidification rollout, expect a question. Have the answer ready before the question arrives, ideally in the same document.

What belongs in the evidence file

Four items, kept together. The collection tickets for the baseline period and the reporting period. The dosage records, showing scoops or kilos used per month. The hauler’s confirmation of the destination and treatment of the loads. And a dated note describing any change in method, such as a new dose card or a change of bin size.

Method changes are where reports fall apart. If you halve the collection frequency in June and report a 40 percent drop in emissions without mentioning it, the number is not wrong but the explanation is missing, and a reviewer will treat the whole page as unreliable.

Language that survives review

Avoid ‘eliminates’, ‘zero’, ‘fully sustainable’ and ‘carbon neutral’. Use ‘reduced’, ‘diverted’, ‘bound’ and ‘measured over’. Say what the baseline is, say what changed, and say what you did not measure.

One manufacturing site I saw did this well in three sentences: baseline year, the change made, and the measured effect, with a note that the water bound in the gel was counted as waste weight and not as discharge. Nobody argued with it, because there was nothing to argue with.

The trap of the supplier’s number

Suppliers publish absorption ratios – 300 times its weight, 400 times, whatever the grade. Those figures come from deionised water in a lab, not from gravy at 40 degrees Celsius. If a sustainability statement quotes a supplier’s absorption ratio as an environmental benefit, a technical reviewer will ask what the ratio is in real waste, and the honest answer is usually a third to a half of the lab figure.

Measure your own. Weigh the waste in, weigh the gel in, and look at the bin at the end of service. That gives you a working ratio for your site, which is the only one that belongs in a report.

If you are drafting the waste section this quarter, the most useful first step is a one-page method note: what you count, how you weigh it, and what you exclude. The polymer specification pages give the test conditions behind the absorption figures, which is exactly the caveat a reviewer will want to see acknowledged.