Process & contact
HAIX ion exchange (LayneRTTM)
Contact: Cranfield University UK, Ana Soares
Input materials
Secondary treated sewage (discharge after biological treatment)
Output products
Orthophosphate solution from which calcium phosphate is precipitated by adding lime
Process description
Selective ion exchange using HAIX (hybrid ion exchange) of hydrated ferric nanoparticles in a strong base anion (quaternary ammonium) resin, using a LayneRT resin base (this is a commercially available arsenic removal resin).
Sodium hydroxide is used to release P from the HAIX iron sites, so generating orthophosphate solution, plus water washing to regenerate the resin.
Operating status
10 m3/day (58 litres, 1.6m high column) demonstration plant operated continuously for 2 ½ years (60 regeneration cycles), with automated bed regeneration, using real WWTP secondary effluent, Cranfield, UK, 2019 -2021.
Inflow 0.7 mgPtotal/l was reduced to below 0.1 mgPPO4+/l.