Chemical-biological treatment of table olive manufacturing wastewater

Wastewater generated in the table olive processing industries has been trea ted by means of an integrated wet air oxidation-aerobic biodegradation proc ess. Chemical oxygen demand (COD) conversion in. the range of 30-60% (6 h o f treatment) has been achieved by using relatively mild conditions (443-483 K and 3.0-7.0 MPa of total pressure using air). Use of the homogeneous cat alysts [copper (IT)] or radical promoters (hydrogen peroxide) resulted in a higher efficiency of the process (roughly between 16 and 33% COD removal i mprovement depending on operating conditions). Biodegradability tests, cond ucted after the oxidation pretreatment, showed a negative effect with the a ddition of copper to the reaction media. Promoted experiments resulted in t he highest values of biodegradability (measured as the ratio of biological oxygen demand to GOD). The rate of the COD biodegradation was compared to t he kinetics of the aerobic process without a previous chemical preoxidation . The calculated kinetic parameters showed the positive effect of the pretr eatment (maximum growth rate of 0.03 +/- 0.006 h(-1) and 0.014 +/- 0.00014 h(-1)). Acclimation of microorganisms to oxygenated species formed in a che mical preoxidation step enhanced the efficacy of the biodegradation (maximu m growth rate of 0.04 +/- 0.007 h(-1)).