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Part 1 of 7 · Waste collection verifier series ~6 min read

A waste collection verifier on AWS for a few dollars a month

The waste invoice is about four hundred pounds a month, it has arrived every month for six years, and it is approved by somebody who has never seen the contract. Two of the four bins are collected half empty. One collection in nine does not happen. Both of those facts are invisible and both of them are paid for.

man in a striped shirt holding a black smartphone
Photo by Super Straho on Unsplash

Key takeaways

  • You cannot claim a missed collection you cannot prove on the day.
  • The invoice has lines the contract does not mention. Check them.
  • Contamination charges are challengeable, inside a window.
  • Right-sizing beats credits by an order of magnitude.
  • Designed on AWS for about $2 a month.

The whole system on one page

Before any code, here is the shape of what we are designing.

System: expected collections, actual collections, and the invoice comparedThree boxes across the top sit outside the AWS account. On the left, The contract, with its schedule, rates and renewal date. In the middle, The bin store, recording what happened on the morning. On the right, The invoice, monthly, itemised and unread. Each connects by an arrow to the AWS account container below. The contract is read once. The bin store reports every collection day. The invoice is checked line by line. Inside the AWS account are three components in a row. On the left, Expected: what you are paying for. In the middle, Actual, with timestamped evidence. On the right, The difference: credits, challenges and the resize. A note says three sources that have never been compared to each other, and that comparison is the entire system.AWS ACCOUNTThe contractschedule, rates,renewal dateThe bin storewhat happened,on the morningThe invoicemonthly, itemised,unreadExpectedwhat you arepaying forActualwith evidence,timestampedThe differencecredits, challenges,and the resizeonce, per contractevery collectiondayline by lineThree sources that have never been compared to each other. That comparison is the entire system.
Fig 1. Three things outside the account, three pieces inside it. Nobody is missing information here; it is in three places and nothing joins them.

Why nobody notices

A missed bin collection is annoying for about two hours and then it is solved by the next collection. Nobody escalates it, because the operational problem goes away on its own, and the commercial problem — that you paid for it — surfaces five weeks later on a line item nobody reads.

The same is true of every other discrepancy here. Each individual instance is too small to chase, and the aggregate is several thousand pounds a year. That is the exact shape of problem that a cheap system is good at and a person is not.

What runs (the inside)

  • Expected. The contract as a schedule and a rate card, so there is something to compare against. Parts 2 and 3.
  • Actual. Evidence captured on the morning, which is the only moment it exists. Part 2.
  • The difference. Credits, contamination challenges, and the fill data that changes the contract itself. Parts 4 and 5.

One month, one site

One site over one month, from expected collections to a resized contractA horizontal row of five boxes joined by arrows. Twenty-two expected, from the contract. Twenty happened, with two carrying evidence of a miss. Invoice shows twenty-two lifts plus three lines nobody recognises. One hundred and eighty-six pounds recovered in credits and one wrong charge. Three hundred and forty pounds a month saved by resizing. A note says the fourth box is what everybody expects from this and the fifth box is why it is worth building.ONE MONTH, ONE SITE22 expectedfrom the contract20 happened2 with evidenceof a missInvoice: 22 liftsplus 3 linesnobody recognises£186 recoveredcredits and onewrong charge£340 a month savedby resizingThe fourth box is what everybody expects from this. The fifth box is why it is worth building.
Fig 2. The same system as one line. Recovering credits pays for the effort; the resize at the end is the actual return.
  • Machine learning
  • Analytics
  • Front-end & mobile

In plain words

The contract is read once into two things: a schedule of what should happen and a rate card of what each thing should cost. That is the only reference point in the entire arrangement, and in most businesses it exists only as a PDF nobody has opened since signing.

On each collection morning, whoever opens up records what they see: bins emptied, bins still full, a photograph if something is wrong. It takes fifteen seconds and it is the only moment at which evidence of a missed collection can exist.

When the invoice arrives it is read line by line against the rate card. Lifts you did not get, rates that are not the agreed rates, escalations applied early, and charges with names that do not appear in the contract at all.

And underneath all of that, the fill levels accumulate quietly for a few months until there is enough evidence to say something useful: that the general waste bin is collected twice a week at sixty percent full, and that one of those two collections is paying for air.

Design rules that shaped every decision

  • Evidence is captured on the day or it does not exist.
  • The contract becomes a schedule and a rate card, not a stored PDF.
  • Every invoice line is matched to a rate. Unmatched lines are questions.
  • Challenge inside the window, because outside it there is no mechanism.
  • Fill data is worth more than credits, and it takes three months to earn.
  • The renewal date is a diary entry with months of notice, not a surprise.

What it does not do

It does not weigh anything, it does not put sensors in bins, and it does not need a single piece of hardware. A person glancing at a bin store and tapping one of three buttons produces data that is good enough for every decision in this system.

It also does not replace the relationship with the waste contractor, most of whom are reasonable when presented with specifics. What it changes is that you arrive with a date and a photograph rather than an impression that collections have been unreliable lately.

The next four posts walk through each piece: how a missed collection gets proved, why the invoice never matches the contract, how a contamination charge gets challenged, and what the fill levels say about the contract itself. One diagram per post, a cost breakdown, and an engineering reference at the end.

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