Data of "Aquatic worms (Tubificidae) facilitate productivity of macrophyte Azolla filiculoides in a wastewater biocascade system"

This was investigated by developing a biocascade with monocultures of plants and aquatic worms that was fed on activated sludge. Tubificidae had an average relative growth rate of 0.02 g g-1 DW d-1 whereby sludge predation resulted in 45% sludge reduction.

When Tubificidae were present in the biocascade, A. filiculoides biomass production significantly increased to a relative growth rate of 0.15 g g-1 DW d-1. The activity of Tubificidae mostly affected total suspended solids, chemical oxygen demand and ammonium concentration in the first compartment of the biocascade. Additionally, nitrification rates increased and the water acidified, leading to increased carbon dioxide concentrations and dissolved phosphorus-binding metals (zinc, iron, aluminium and manganese) that stimulated A. filiculoides growth.