Until recently, real-time monitoring of BOD was unattainable owing to its complex nature. Recent research by a leading UK university has discovered the link between multiple water quality parameters including electrical conductivity, turbidity, TLF and CDOM. These parameters are all capable of being monitored in real-time through a combination of traditional methods (electrical conductivity via electrodes) and newer methods such as fluorescence. The monitoring of tryptophan-like fluorescence (TLF) has been successfully utilised as a proxy for biological activity and enumeration, particularly with a focus on Escherichia coli (E. Coli). TLF based monitoring is applicable across a wide range of environments, including but by no means limited to sewage treatment works and freshwaters. Therefore, there has been a significant movement towards combined sensor systems that can monitor parameters and use them, in real-time, to provide a reading of BOD that is of laboratory quality.