Sequencing batch reactor technology for the purification of concentrated dyehouse liquors

A sequencing batch reactor (SBR) technology for the purification of concentrated reactive ate-dye containing residual dyehouse liquors from a padding process was developed and investigated. Within the treatment cycle, the anoxic dye cleavage, the aerobic mineralization of organic compounds, in combination with the biodegradability-achieving partial oxidation with ozone, are carried out sequentially. Anoxic decolourization of the residual liquor without addition of an auxiliary substrate was observed, and a 90% biological degradation of the dyehouse liquor's recalcitrant organic compounds was achieved. COD decreased by 95% and AOX (adsorbable organohalogenic compounds) by 90%. Within the whole process, the colour of the concentrated wastewater decreased by 98%.