  Prediction and optimisation are two widely used techniques that have found
many applications in solving real-world problems. While prediction is concerned
with estimating the unknown future values of a variable, optimisation is
concerned with optimising the decision given all the available data. These
methods are used together to solve problems for sequential decision-making
where often we need to predict the future values of variables and then use them
for determining the optimal decisions. This paradigm is known as forecast and
optimise and has numerous applications, e.g., forecast demand for a product and
then optimise inventory, forecast energy demand and schedule generations,
forecast demand for a service and schedule staff, to name a few. In this
extended abstract, we review a digital twin that was developed and applied in
wastewater treatment in Urban Utility to improve their operational efficiency.
While the current study is tailored to the case study problem, the underlying
principles can be used to solve similar problems in other domains.
