Stirling Council – Waste Services Case Study

Vintage Ordinance Survey Map of Stirling
Vintage Ordinance Survey Map of Stirling

Wittin was working with Waste Services at Stirling Council to prove the concept of applying citizens as data scientists against operational and transactional data. The goal was to understand the value within waste services data and to explore options of solving the challenges presented by waste services.

We decided to run a hackathon at CodeBase Stirling at the end of November 2017 to explore the challenges and the data and see what understanding or solutions we could develop over a 24 hour period. We started the day with presentations about the format from Wittin and about the challenges from Waste Services. From then on we used our time to explore understanding and visualisation of the data as well as ultimately coming up with solutions to the challenges.


Four challenges were presented on the day:

Bio Bags Challenge
Exploring the cost and distribution associated with food waste bags across Stirling Council.

Brown Bins Challenge
Minimizing the variability of the collection of brown bins.

Glass Collection Challenge
Looking at the frequency of collection and how to best minimize these collections with the minimal amount of disruption.

Recycling Targets Challenge
Increasing all waste going to recycling from 61% currently to 70% by 2025.


The data we gathered for the hackathon was of two types. The first was transactional data: eFinancials Accounting 2015 to 2017, Lagan CRM 2015 to 2017 and Facebook Posts from Stirling Council’s account. The second was operational data: pay scales, refuse collection heat maps, vehicle specifications, refuse collection risk assessment, additional bin policy, alternative delivery model routes, details or routes, vehicles and manning, and recycling weights.

The hackathon also spent a few hours quizzing the waste services team on their operations and their own insights on the challenges.

On the day, after sifting through the data we had access to, and through the conversations held with the waste services team, we collectively chose to focus our efforts on two challenges, namely the bio bags challenge, and the recycling targets challenge.

Starting to Understand Bio Bags

Focusing first on the bio bag challenge. We started with the estimated average household waste per household in Scotland the report: Report Identifies 145kg per household per year as measured in an extensive study in 2009.

Then looking at average numbers of occupants in a household the report: Report we see there is an average of 2.16 occupants per household in 2016 and math allows us to deduce 67.13kg of food waste per person per year.

Then the number of households are broken down into the number of occupants in a report that has since been removed from the National Records of Scotland website. The total was 39,713 Stirling households in 2017. Instead of finding a current estimate I’ve kept the original project we used.

From that, we can see that we are servicing 85,780 individuals creating 5,758 tonnes of food waste per year. If a 7 Litre bag on average is thrown away containing 1kg of food waste as per Stirling’s estimates: Stirling Council Website (2 to 3 a week covering an average of 2.78 kg of food waste) Then we can estimate that if 7 Litre bags come in rolls of 30 at a cost of £0.02 per bag then…

Where does that leave us?

If 39,713 households are generating 145kg of food waste we get 5,758,385kg of waste per annum out of Stirling Council households. If there are 30 7 Litre bags in a roll we see that a household requires 5 rolls including a 3.5% overestimate which will cover spoilage (tearing) and alternative uses such as animal waste collection (which is not an undesirable outcome).

So 5 rolls per household and 39,713 households require 198,575 rolls of BioBags. This represents a total of 5,956,950 individual bags which maintains a 3.4% average of overestimating necessary bags across the council.

The cost of bags is suggested to be £0.02 per bag (as indicated by the figures put forth by Waste Services). Making a total spend on just purchasing bags to be £119,139.

This is far greater than the estimates of £40,000 per annum current suggested in 2017.

Going in Another Direction

Pulling the figures back to household prices we see a cost of £3.00 per household to accomplish this requirement.

Current spend would see £1.01 spent per household on BioBags.

However, instead of looking at this as a failure to cover the requirement of a citizenship we can use the discrepancy to define the amount of food waste that is currently going to landfill.

So £1.01 (if we are being generous) indicates a third of all food waste is making it to recycling. So two-thirds of 145kg is going to landfill. That represents 95.7 kg per household or 3,800 tonnes of Food Waste in total.

Bringing it All Together

What is still required in this figure would be the delivery of 5 annual rolls which could be done once a year a cost to be determined. Then perhaps an educational piece of work pushing use and we can see this work towards reducing landfill by up to 3,800 tonnes a year.

Using the figure that each household discards 1.2 tonnes of waste per year then 95.7 kg represents a 7.98% gain for Recycling Targets.

Distribution changed from open distribution to one annual manual delivery of 5 bags per household.

Cost is free for annually delivered bags, but additional bags can be purchased from the council at below market rates (£1.00 per roll?). Revenue stream to offset costs.

Increased recycling of food waste should generate revenue through selling to compost/energy generating companies. To offset costs.

To make this project work there would be required an un-costed element of education of how to use the bags and promote their use effectively taking food waste out of the landfill waste and into the recycling waste.

Also, it would be possible to offer money for unwanted bags. If a roll currently costs £0.60 returned bags could be purchased back for £0.20 a roll. This means that there is an incentive for people who don’t want to engage with the scheme to return the bags replenishing Stirling Council stock with bags at a third of the cost.


Sometimes the best way to solve a problem is not to solve it. In this case, by increasing the spend on bio bags we can reap massive savings on the reduction of waste going to landfill.

We successfully found that we could apply a community of interested parties against transactional and operational data from the public sector and generate solutions to current challenges.

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Born into the wilds of mid-western America, Matthew has lived his life creating. The kind of kid that bought a tarp, some PVC pipe and a skate board; fashioned himself a windsurfing set-up and then saw an opportunity in a local tornado. "Sorry Mom." Undergraduate in Art and Design, Doctorate in Scottish History, Matthew came late to the realisation that if he's going to use his diverse skill set he'd have to employ himself.