Weight tickets and waste reports: numbers an auditor will check

The site reported 4.2 tonnes of food waste for the month. The hauler’s invoices, added up, came to 5.6 tonnes. The difference was 1.4 tonnes, which at the contract rate was worth more than the gel bill for the whole year, and the auditor wanted to know which number was wrong.

Neither was. The site was reporting the weight of food they thought they had thrown away, from production records. The hauler was weighing bins, including the water bound into the gel and the packaging nobody counted. The gap was real, and it had been growing for eight months.

The three documents that have to agree

Any waste audit, whether it is a customer’s procurement review, a certification body or a landlord’s compliance check, ends up triangulating three sources. The weighbridge tickets from the hauler. The invoices that follow them. And your own internal log, if you keep one.

Most sites keep the first two and improvise the third. That is why the numbers drift. A ticket says 18.42 tonnes for the collection; the invoice applies a rate per tonne and a fixed charge; your kitchen manager records ‘about twelve bins’ in a diary. When someone asks how much waste you produce, three people give three answers.

Tare, gross and the bin that weighs 40 kilos

The weighbridge gives a gross weight for the vehicle before and after tipping, and the difference is the load. That is the number on the ticket, and it includes the bins if they go over the bridge with the load – which they do on some collection types and not others. Ask which. A four-bin collection with 240-litre bins can carry 160 kilos of empty bin, which is 4 percent of a four-tonne load and enough to explain a small variance on its own.

Your own log should record net weight where you can get it. A platform scale under the bin, read at the point of closing, gives you a figure within a few kilos and costs less than a single rejected load. Weigh the same bin three times over a week and you will see how much of your variance is measurement noise rather than behaviour.

Why 6 percent is normal and 15 percent is not

Some variance is structural. Gel binds water that would otherwise have run away, so solidified waste is heavier per cover than the same menu without gel – often by 5 to 10 percent. Seasonality moves it further. If your baseline was set in February and you are comparing to August, you are comparing two different menus.

A variance above about 15 percent, sustained over two months, usually points at something specific. Wash water going into the bin instead of the drain. A second dose applied by a new starter. A collection that was skipped and rolled into the next invoice. Or a bin that was overfilled and charged at a higher rate.

The counterintuitive part is that a sudden drop in weight is often worse news than a rise. It can mean the gel is no longer binding and liquid is leaving the bin before the weighbridge – which shows up as a clean ticket and a dirty yard.

Building a one-page monthly reconciliation

Four columns are enough. Collection date. Ticket weight. Invoice charge. Internal log weight. Add a fifth column for the variance as a percentage, and a sixth for a one-line note on anything unusual: a missed collection, a menu change, a new starter, a bank holiday.

Fill it in monthly, not weekly. Weekly reconciliations get abandoned in busy periods; monthly ones survive. Keep it in the same place as the contracts, and give a copy to whoever signs the invoices.

What the auditor actually asks

Three questions, almost always. How do you know the weight? Can you show me the records for the last twelve months? And what happens when the numbers do not match? The first is answered by the tickets, the second by the file, and the third by the variance column and its notes.

One hotel group failed a pre-certification review not because the numbers were bad but because the person presenting them could not explain a 19 percent spike in one month. The spike turned out to be a wedding season and a change of menu, entirely benign. Nobody had written it down, so it read as an unexplained anomaly.

If you want the reporting to hold up, start with three months of tickets, build the six-column sheet, and write a sentence for every variance over 10 percent while you still remember why. That habit is worth more than a software platform. The solidification user guide includes a blank version of the sheet if you want a starting layout.