Photo Activated Sludge

IHE Delft is working with IIT Delhi to pilot a photo activated sludge system to remove nutrients from the drain water of the Barapullah Drain. In Pavitra Ganga it will be tested in combination with cleaning blocks.

Working principles

 The key principle is to grow a mixed biomass of algae (and phototrophic cyanobacteria) and selected bacteria. The latter could be ordinary heterotrophs, nitrifiers or in special cases anammox bacteria. PAS technology is different from regular pond systems, in that it optimises the mixed culture and the observed volumetric removal rates are much higher, because of higher biomass concentration and gentle mixing.

scheme photoactivated sludge

Main Goals

  • Natural system with better effluent quality
  • Significantly less complicated than activated sludge
  • Under tropical conditions <0.5 m² per population equivalent
  • Net energy producer, no mechanical aeration, algae biomass production and anaerobic biomass digestion
  • Nutrient recovery (P)
  • Good disinfection

PAS system

Involved partners