Enricher-reactor bioaugmentation of activated sludge for degradation of hazardous wastewaters

A novel process scheme for biological treatment of hazardous wastewaters was developed a validated through bench-scale activated sludge (AS) experiments and model simulations. Hazardous tastes are difficult to degrade with conventional AS systems because of toxicity, unsteady composition, and discontinuities which make it difficult or impossible to maintain a continuously acclimated culture.; A continuously acclimated culture can be maintained using bioaugmentation, thereby enrichment cultures (ECs) are used to supplement the indigenous culture. An EC was developed to degrade 1-Naphthylamine (1NA) a regulated carcinogen and known biological inhibitor, degradation of which had not been extensively studied previously. The kinetics of 1NA degradation were quantified. Losses due to abiotic mechanisms (volatilization and adsorption) were quantified. The culture was shown to mineralize 1NA to CO{dollar}sb2{dollar}, as a sole source of carbon and energy.; The 1NA-degrading EC, maintained on high concentrations of 1NA, was used to inoculate several continuous-flow reactors (CFSTRs) daily with different quantities of cells. Bioaugmentation was quantified as "bioaugmentation level" (mass of inocula added per day/mass of cells present in the CFSTR at steady-state). Bioaugmented and control CFSTRs were subjected to a step-increase loading, shock loading, and disacclimation followed by reacclimation. Reactors which received higher bioaugmentation levels outperformed those which received lower levels (decreased 1NA effluent breakthrough). All bioaugmented reactors outperformed acclimated and unacclimated controls.; Sub-cultures of the original EC which were maintained on inducer compounds (structurally similar but less hazardous than 1NA) and not exposed to 1NA, were shown to retain the ability to degrade 1NA. These cultures were then used to bioaugment several CFSTRs and their performance relative to the original EC was examined during several dynamic loading conditions. Several of the induced cultures were shown to be nearly as effective as the original EC.; The effects of bioaugmentation on the observed steady-state biomass concentration was examined in relation to that predicted by mass-balance considerations. A dynamic kinetic model was developed to simulate the proposed process and aid in scale-up design.