Optimizing upflow velocity and calcium precipitation in denitrifying granular systems

- Study of the granulation of denitrifying biomass in USB reactors.
- Upflow velocity and calcium concentration optimization to speed up granulation.
- Minimum values for stable granules formation: vup = 0.19 m h−1 and [Ca+2] = 60 mg L−1.
- Low required values of vup and calcium concentrations diminished operational costs.
- High treated nitrogen loads (2.0-3.5 g N L−1 d−1) at high removal efficiency (>98%).