In the various regions in which we operate, local legislation governs landfill use and is quite diverse. However, there is a common goal to reduce the impact wherever and whenever possible. Within four of our major locations, and as a result of local regulatory requirements, we operate our own waste water treatment plants. In the fifth, Scotland, we partially treat our effluent to ensure we meet the outflow parameters before discharging directly into the public sewerage system, where our waste is combined with domestic effluent and treated by Scottish Water.
Our 2020 target was zero waste to landfill. We have made significant progress over the last five years and although we fell short of our zero waste target for 2020, our actions have reduced our waste to landfill per million metres production by 91% since 2015. This has been achieved through minimal investment. By separating out non-compostable items and using biodegradable bags for our organic waste, we are able to generate circular economy benefits by sending the vast majority of our collagen waste to anaerobic digestion and hence, third-party energy generation. We remain focused on finding new avenues for our process waste and continue to evaluate new technologies with our business partners.