Degradation of AZO Dye in fixed film Bioreactors: A bench scale study

The inorganic (5 ppm P04-P and 50ppm N03-N) and organic (30MI day] milk whey) nutrients were examined on degradation of Methyl Red (MR) at different hydraulic retention time under aerobic and anaerobic conditions in two different bioreactors; one having only gravel soli matrix while the other having 75% gravel and 25% coarse river sand solid matrix. The physico-chemical properties of the bioreactor outflows were monitored in terms of colour removal and COD load reduction. In toxicity assessment bioassay Lemna was found to be most sensitive candidate. The outflows from aerated bioreactors were found non-toxic to Lemna while, COD load reduction (63–70%) and decolourisation (90–94%) was also reported higher.