An insight on achieving low phosphorus and low iron on a trickling filter works: PRESENTATION ONLY
Mariana Pinheiro, Process Design Engineer, Southern Water, UK
(Free)
The brief
Upgrade the works as required to meet the new Total Phosphorus (TP) permit of 0.25 mg/l as a rolling 12 months mean whilst maintaining compliance with the other permit determinands.
In reality TP permit will drive the TSS limit to ~ 3 mg/l
The Old Works
– Conventional trickling filter (TF) works with single point ferric dosing
– Ferric mixing achieved by running the recirculation constantly to the PST distribution chamber
– Ferric and recirculation both inhibited in storm conditions
– Pyramidal PSTs with adequate capacity- Adequate biological capacity for permit
– Pyramidal HSTs marginally short of capacity at peak flows