Name
Balancing nitrate and phosphorus removal in denitrifying sand filters
Speakers
Connor Sandalls
Authors
Imran Baloch, Connor Sandalls and Shirly Lang, Southern Water, UK
Description
Southern Water has 12 No. operational WwTWs with Total Nitrogen (TN) permits of 15 mg/l or tighter. These works treat about 22% of Southern Water total PE. Type of treatment for TN removal varies from denitrifying sand filters on trickling filter works to MLE or 4-stage Bardenpho for activated sludge processes.
Bishops Walthan WwTW is a trickling filter works treating 15,000 PE with a FFT of 107 l/s. Site TN permit of 15 mg/l is achieved by dosing methanol in denitrifying sand filters. AMP7 driver imposes a low Total Phosphorus (TP) permit which challenges the operation of the site to achieve TN and TP limits simultaneously. Achieving low TP limit with tertiary denitrifying sand filters is limited by the need to have sufficient phosphorus available as a nutrient for denitrifiers to meet TN limit.
Southern Water wastewater process engineering team performed an extensive trial on site and outcome of the trials were used for scoping the solution for achieving TN and TP permit.
The presentation would provide insight on the performance, optimisation measures, operational experience and lessons learnt of the full-scale installation.
This presentation would cover following areas:
• Insight on decision making process to provide dedicated ferric dosing points (second point ferric dosing) for each humus tank to provide flexibility to optimise the amount of phosphorus to be removed.
• Concentrations of phosphorus required for denitrification process.
• Benefits of installing online monitoring on the feed to the denitrifying sand filters for controlling TP and TN concentrations in the final effluent.
• Providing intelligent ferric dosing control to ensure there is sufficient phosphorus available as a nutrient for denitrifying sand filters.
Time
11:10 AM - 11:35 AM
Location Name
Room 1
Track
09:00 - 15:45 Phosphorus