Granular activated carbon promoted ozonation of a food-processing secondary effluent.
This paper reports on the application of a simultaneous combination of ozone and a granular activated carbon (O(3)/GAC) as a tertiary treatment of a wastewater generated from the activity of various food-processing industries. Prior to the O(3)/GAC treatment, the wastewater was subjected to conventional primary and secondary treatments in a full-scale wastewater treatment plant (WWTP). The effluent from the WWTP presented high organic load (COD>500 mg/l and TOC>150 mg/l), which could be much reduced by the O(3)/GAC treatment. Results from the O(3)/GAC experiments were compared with those obtained in single ozonation, single adsorption onto GAC and sequential O(3)-GAC adsorption experiments. While single processes and the sequential one showed limited capacity to remove organic matter for the food-processing effluent (COD removal <40%), the simultaneous O(3)/GAC process led to decreases of COD up to 82% at the conditions here applied. The combined process also improved the ozone consumption, which decreased from about 19 g O(3)/g TOC (single ozonation process) to 8.2-10.7 g O(3)/g TOC (O(3)/GAC process). The reusability of the GAC throughout a series of consecutive O(3)/GAC experiments was studied with no apparent loss of activity for a neutral GAC (PZC = 6.7) but for a basic GAC (PZC = 9.1).
Alvarez
Pedro M
PM
Departamento de Ingeniería Química y Química Física, Universidad de Extremadura, 06071 Badajoz, Spain. pmalvare@unex.es
Pocostales
J Pablo
JP
Beltrán
Fernando J
FJ
D000327:Adsorption; D002244:Carbon / Q000737:chemistry*; D019649:Food Industry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D007700:Kinetics; D010126:Ozone / Q000737:chemistry*; D010316:Particle Size
D007220:Industrial Waste; D010126:Ozone; D002244:Carbon