Sludge optimisation – searching for the Holy Grail
Auty, D., Entec UK Ltd, UK
(free)
Ever since sludge was first created, practitioners have been searching for the best thing to do with it. A very experienced sludge man once described this as like searching for the Holy Grail. Sludge is created in many different ways, each one of which changes the nature of the sludge. It is then transported to any of a number of possible treatment centres. It is then treated in many different ways, each one of which is affected by the nature of the sludge and imparts changes to the nature of the sludge. The treated product then has the option of where to take it for recycling/disposal and each of these outlets has restrictions that limit their availability. Working through the maze of options created by this sludge journey and trying to pick out the best thing to do with it is impossible in human terms – hence the reference to the Holy Grail. To add to the burden is the constant pressure to minimise capital and operating costs and the urgent need to reduce the carbon footprint of not only the operations, but also of the sludge itself. In fact, sludge is a great organic resource that we, as an industry, would try to make more of, if only we knew how to optimally manage it
This paper will reveal and describe the true complexity of sludge optimisation and then demonstrate a solution that has been developed by Entec in conjunction with Scottish Water, Severn Trent and Thames Water. This solution is a computer model that takes a holistic view of the whole sludge lifecycle and captures years of experience from sludge practitioners. This enables them to manipulate the data to find the optimum solution for what to do with their sludge. To make it easier, the process can even be done automatically.
It’s not quite the sludge man’s Holy Grail yet, but it is a good step along the journey and with this paper we are hoping to provide some enlightenment.
