Packed-Column of Granular Activated Carbons for Removal of Chemical Oxygen Demand from Industrial Wastewater

摘要

In the present study, chemical oxygen demand (COD) removal by packed-columns of activated carbon (AC) derived from two different materials (coal activated carbon, CAC and wood activated carbon, WAC) is reported as part of an on-site wastewater treatment system for handling small volumes of wastewater generated at wood-floor industries for which there are no proper on-site treatment options available in the market. The performance of the sorbents, the effect of bed depth (0.19 and 0.57 m) and volumetric load (0.10 and 0.24 m h−1) on the breakthrough curve of sorption systems were studied. The results indicated the feasibility of using both ACs to treat these wastewaters. At the bed depth (0.57 m), volumetric load (0.24 m h−1), and 30% breakthrough, CAC and WAC showed treatment capacity of 40.5 L kg−1 in 250 h and 23.8 L kg−1 in 63 h, respectively. This indicated that CAC requires longer retention times to reach a performance similar to WAC. The experimental data was fit into the bed depth-service time model showing that under the same conditions, CAC had higher maximum sorption capacity (N0) than WAC. Moreover, thermal regeneration at 500°C temperature could be a cost-effective procedure since the reuse of spent AC through such regeneration process for further treatment could still achieve 90% of the initial sorption capacity, reducing then costs for the use of new sorbents and also the need for waste disposal.