News
Walnut pilot site aims to recover nitrogen from reject water
Operations have started in Spain at the Ourense’s wastewater treatment plant
Overview
Responsible partner: CETAQUA
Type of feedstock: Reject water
Nutrients recovered: Nitrogen as ammonium nitrate
Process technologies: Filtration unit; Ion exchange; Hollow Fibre Membrane Contactors
Description
The aim of this pilot plant is to recover nitrogen from reject water. It consists in three main units: a filtration pre-treatment process to remove the suspended solids presented in reject water; an ion exchange column loaded with 0.5-1 mm zeolites for nitrogen concentration; and two membrane contactors with an unitary surface of 1.4 m2 (3M™ Liqui-Cel™ EXF-2.5×8). These membranes allow the ammonia transport from the feed solution and to the acid one, in this case, nitric acid, producing ammonium nitrate which is free of PTEs and organic micropollutants (OMPs) because the selected membrane is gas permeable and none of these compounds should pass through.
