Introduction: Over the last decade there has been a shift in global thinking around sustainability with increasingly strong evidence of anthropogenic climate change. As a result governments have started to make the monitoring and reporting of greenhouse gas emissions (CO2e) mandatory.

The United Kingdom (UK) National Health Service (NHS) is estimated to have an annual carbon footprint of 21 million tonnes of CO2e, part of which results from waste production and disposal. Over £82 million is spent on the disposal of waste by the UK NHS annually. By reducing the amount of waste produced, reusing items where appropriate and recycling waste where possible both financial and environmental savings can be achieved.

This project utilised an empirical data set describing the composition of health and social care clinical and domestic waste streams to produce a program modelling the financial cost and CO2e emissions associated with current waste management practices. Furthermore, scenarios of waste reduction and recycling could be produced based on this model describing the savings that could be made to aid the facilitation of behaviour change.

Data was collected from four health and social care sites in the South West of England. Forty six bags of waste (83.55kg) from municipal waste streams and 69 bags of waste (196.60kg) from clinical waste streams were catalogued.

The program generates a set of bag parameters based on the empirical data set. It then satisfies these parameters by selecting items from the known item list using their probability of occurrence also based on the empirical data. Once the simulated bag has been populated the CO2e and cost of disposal for each item and the bag overall are calculated. This process can be carried out to simulate a given number of waste bags in a particular waste stream.

A regression model is then produced describing the financial cost and CO2e for the simulated data. Based on the resulting regression equation the annual waste costs and CO2e for a given amount of waste can be estimated and reduction scenarios produced (e.g. 5% to15% reductions).

The final program will incorporate a forward facing graphical user interface to allow easy user interaction.

The program in its current form provides health or social care sites with an estimation of their waste disposal cost and CO2e emissions for one year based on either the known waste amount or the number of bed places on-site. Furthermore the program provides a set of waste reduction scenarios complete with financial and environmental savings.

This program can be used to encourage health and social care organisations to adopt a reduce, re-use, recycle philosophy. Being able to visualise the real benefits of such a system will provide useful information to inform change. Program users will be able to track their progress and deviation from ideal targets set by the model over time as they implement a new or revised waste management system.

The program will be subject to on-going development and will provide increasingly accurate estimates as more data is included.