First demonstration of hydrophobic membrane contactors forremoval of ammonia from condensate wastewater

Hydrophobic membrane contactors represent a promising solution to the problem of recovering ammoniacal nitrogen from wastewater. The process has been shown to work best with wastewater streams that present high ammonia concentrations, low buffering capacities and low total suspended solids. The removal of ammonia from rendering condensate, produced during heat treatment of waste animal tissue, was assessed in this research using a hydrophobic membrane contactor. The main objective was to test the ammonia stripping technology using two types of hydrophobic membrane materials, polypropylene and polytetrafluoroethylene, at pilot scale and carry out process modification for ammonia removal. The results demonstrate that polypropylene membranes are not compatible with the condensate waste as it caused wetting. The polytetrafluoroethylene membranes showed potential and had a longer lifetime than the polypropylene membranes, removing up to 64% of ammonia from the condensate waste. The product formed contained a 30% concentrated ammonium sulphate salt which has a potential application as a fertilizer. This is the first demonstration of hydrophobic membrane contactors for treatment of condensate wastewater.