Design of a crystalliser Urine treatment for phosphoruous recovery via potassium struvite precipitation

Optimising te flow patterns of the crystals while preventing wash out

We designed a crystalliser for treatment of human urine. Phosphorous was recovered in the form of potassium magnesium phosphate (K-struvite). Urine and xxx entered the reactor in the middle near the impeller. Different baffle configurations and impeller speeds were tested in order to find the optimal flow pattern (recirculation of crystals and no local crystal holdup or wash out).

Major findings

  • Some designs led to local recirculation zones at the top of the reactor, capturing crystals and preventing them from recirculating
  • The height of the middle shaft was critical (could give rise to crystal wash out)
  • An optimal impeller speed existed: optimal mixing of chemicals and creating an optimal upward velocity in the shaft

Improving mixing in large WWTP

CFD Activated Sludge WWTP

Improving aeration in a WWTP

CFD Activated Sludge WWTP

Secondary settler optimisation

Secondary Settler CFD-PBM

Quantifying N2O emission in WWTP

CFD N2O WWTP Activated sludge

Ion exchange optimisation

Ion Exchange CFD Optimisation

Improving mixing in a water reservoir

Drinking Water Reservoir Flow Pattern