From universal agreements to wild contradictions: the different approaches to chemical phosphorus removal across the UK wastewater industry: PAPER & PRESENTATION
Hernandez-Ramirez, O. and Thompson, A.
Atkins SNC Lavalin, United Kingdom
(free)
Water companies in the UK are currently facing unprecedented tightening of phosphorus consents, which will only become tighter in the upcoming AMPs.
Historically, the most widely applied method of phosphorus removal has been chemical precipitation through the addition of iron or aluminium salts. Although more sustainable options, such as biological processes, are already being implemented at key sites, data shows that chemical removal is likely to remain an integral part of wastewater treatment – whether as the main method in small or problematic
works, or as a trim for meeting consents below 1mg/L, not achievable through biological removal alone.
All water companies have developed asset standards and internal guidelines for chemical precipitation at existing works. However, the approach has not been consistent throughout the sector, with wide variations of criteria, brackets and rules of thumb.
This paper collates and compares these approaches, looking at asset standards and guidelines from most of the water companies in the United Kingdom. The methods stated in these standards have been applied for the sizing of chemical phosphorus removal on four simulated sites, to meet theoretical consents based upon the future discharge requirements set by the Environment Agency under the WINEP programme.
Keywords
Asset standard, Chemical dosing, Design, Ferric, Phosphorus.
