Gallagher, M., United Utilities(free)
In previous National Environment Programmes, water companies received funding to install MCERTS flow measurement at Wastewater Treatment Works (WwTWs) in order to measure the volume of treated flow discharged into receiving waters and to assess Dry Weather Flow (DWF) compliance. As the location for the flow device isn’t prescribed it is sometimes located at the works inlet but in many cases to avoid the complications of double counting, due to recirculation flows, it is at the outlet.
To prevent more frequent, higher strength and longer duration discharges, the Environment Agency is now focussing on Pass Forward Flow (PFF) Compliance. In AMP7 all WwTWs with a permitted DWF > 50 m3/d and PFF controlled by a storm overflow will be assigned a U_MON3 (Event Duration Monitor on storm overflow weir) and U_MON4 driver (MCERTS flow measurement device immediately downstream of the overflow). In order to reduce the potential expenditure of relocating MCERTS flow meters a recent UKWIR project studied using outlet flow meters for assessing PFF compliance, and the EA has created another driver (U_INV2) which enables this option to be investigated.
This presentation will give an overview of the AMP7 flow compliance drivers, outputs from the UKWIR project (author on the steering committee) along with practical examples of the technical and financial challenges faced whilst working on the AMP6 Flow4 programme, which was a precursor to the AMP7 flow drivers.