On-site treatment of textile yarn dyeing effluents using an integrated biological–chemical oxidation process|
Lotito, A. M.; De Sanctis, M.; Rossetti, S.; Lopez, A. & Di Iaconi, C.
This paper reports the results of the treatment
of a yarn dyeing effluent using an integrated biological–
chemical oxidation process. In particular, the biological
unit was based on a sequencing batch biofilter granular
sludge reactor (SBBGR), while the chemical treatment
consisted of an ozonation step. Biological treatment alone
was first performed as a reference for comparison. While
biological treatment did not produce an effluent for direct
discharge, the integrated process assured good treatment
results, with satisfactory removal of chemical oxygen
demand (up to 89.8 %), total nitrogen (up to 88.2 %),
surfactants (up to 90.7 %) and colour (up to 99 %), with an
ozone dose of 110 mg of ozone per litre of wastewater.
Biomass characterization by fluorescence in situ hybridization
has revealed that filamentous bacteria represented
about 20 % of biomass (coherently with high sludge volume
index values); thanks to its special design, SBBGR
guaranteed, however, stable treatment performances and
low effluent suspended solids concentrations, while conventional
activated sludge systems suffer from sludge
bulking and even treatment failure in such a condition.
Furthermore, biomass characterization has evidenced the
presence of a shortcut nitrification–denitrification process.
Yarn dyeing wastewater; Biological treatment; Ozonation; Integrated treatment; Biomass characterization