Design and economic aspects of activated carbon adsorption in relation to the effect of dissolved oxygen

Phenol and o-c resol adsorption isotherms and columns were run under anoxic and oxic conditions. Both rests indicated that the adsorptive capacities under oxic conditions were 80%-160% higher than under anoxic conditions with very close agreement between the column and isotherm capacities. Throughput waste volumes processed in oxic columns were 70-169% higher than in anoxic columns. The economics of this oxygen-induced enhancement in sorptive capacities was addressed. Savings of 30% and 50% in operational treatment cost were estimated for o-cresol and phenol for parallel adsorber and serial schemes under oxic conditions while no differences between these two schemes in terms of the economics of this phenomenon were observed. Sensitivity analysis revealed that 15% and 30% loss of savings are included upon increasing the cost of GAC three-fold, for phenol and o-cresol respectively. The overall cost of oxic treatment was insensitive to the cost of oxygenation, exhibiting only a 14% increase for quadrupling the cost of oxygen. Higher oxic sorptive capacities not only results in greater savings of operational treatment costs but also less sensitivity to fluctuations in GAC and oxygenation costs.