With one of the largest geographic catchments of all UK water companies, Anglian Water recently considered the efficient regulation of its treatment processes, reduction of energy consumption and the cost of treatment.
An area where a substantial amount of energy could be reduced was through the efficient control of the nitrification process treatment, which is used to reduce ammoniacal-nitrogen concentrations in wastewater. Traditionally, biological treatment was controlled by installing dissolved oxygen monitors, however this led to over aeration and energy waste, and could also affect the treatment.
As energy costs increased alternative control methods were implemented. The use of continuous ammonia measurement within the aeration ditch to provide real-time control based on ammonia concentrations was implemented.
WTW ammolytplus technology was installed at Charlton WwTW for feed forward control, and then at Leighton Linslade WwTW to accommodate feed forward and feed back control using a common transmitter. The aeration process was maintained to achieve a target concentration of 2.0mg/L as N and the feedback sensor location was installed for this purpose. A further installation at Chantry WwTW provided feed back control to the nitrification process.
Many systems have also been installed for final effluent monitoring to identify that the treatement process is correctly removing ammonia from treated effluent.