Nitrogen Removal from Ink-Jet Textile Printing Wastewater by Autotrophic Biological Process: First Results at Lab and Pilot Scale

Digital textile printing is a rapidly spreading technology in the textile finishing industry due to the great advantages in making printing much more flexible. On the other hand, wastewater originating from rinsing baths are rich in nitrogen (up to 600 mg/L of ammonium nitrogen) due to the massive use of urea in conditioning the textile before printing. Such high concentration prevents the direct discharge into water bodies or even in public sewers and specific dedicated on-site pre-treatment is necessary. PN/anammox processes can offer an economically feasible alternative to conventional nitrogen removal processes, as these require a COD/N ratio of at least 8. The first results of the EU-LIFE DeNTreat project, consisting in the start-up of PN/anammox lab and pilot scale reactors are promising in spite of the variability of the characteristics of the wastewater originating from rinsing digitally printed textiles.