Complete treatment of olive mill wastewaters by a wet air oxidation process coupled with a biological step

The non-catalytic wet air oxidation (WAO) of olive mill wastewaters was investigated. The effect of operating conditions, such as initial organic loading (1,000 and 4,500 mg/L COD), reaction temperature (140 and 180°C), treatment time (1 and 4 h), initial pH (4.8 and 7) and the use of 500 mg/L H2O2 as an additional oxidant, on treatment efficiency was assessed implementing a factorial experimental design. Of the five parameters tested, the first two had a considerable effect on COD removal, while treatment time was of no significance implying that all oxidation reactions occur during the first hour of treatment. Although the level of mineralization was generally moderate, this was accompanied by nearly complete total phenols and color removal. The analysis was repeated at more intense conditions, i.e. initial COD up to 8,000 mg/L and reaction temperature up to 200°C; at this level, none of the studied effects were important. However, at optimal experimental conditions (i.e. 180°C, 1 h treatment and initial COD of 8,100 mg/L) WAO yielded 34, 94 and 74% removal of COD, total phenols and color respectively. Moreover, ecotoxicity to V. fischeri was slightly reduced after 2 h of treatment at the above conditions.

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Model identification of wet-air oxidation process thermal decomposition

Water Research ◽

10.1016/0043-1354(70)90019-9 ◽

1970 ◽

Vol 4 (1) ◽

pp. 33-59 ◽

Cited By ~ 12

Author(s):

Takeichiro Takamatsu ◽

Iori Hashimoto ◽

Suteaki Sioya

Keyword(s):

Thermal Decomposition ◽

Oxidation Process ◽

Model Identification ◽

Air Oxidation ◽

Wet Air Oxidation

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Wastewater treatment by catalytic wet air oxidation process over Al-Fe pillared clays synthesized using microwave irradiation

Frontiers of Environmental Science & Engineering ◽

10.1007/s11783-017-0971-1 ◽

2017 ◽

Vol 12 (1) ◽

Cited By ~ 17

Author(s):

Halima Sassi ◽

Gwendoline Lafaye ◽

Hédi Ben Amor ◽

Abdelaziz Gannouni ◽

Mohamed Razak Jeday ◽

...

Keyword(s):

Wastewater Treatment ◽

Microwave Irradiation ◽

Oxidation Process ◽

Pillared Clays ◽

Catalytic Wet Air Oxidation ◽

Air Oxidation ◽

Wet Air Oxidation

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Removal of Phenol in Wastewater by Wet Air Oxidation

Water Quality Research Journal ◽

10.2166/wqrj.1973.011 ◽

1973 ◽

Vol 8 (1) ◽

pp. 148-167 ◽

Cited By ~ 1

Author(s):

B.B. Pruden ◽

D.R. Ferguson

Keyword(s):

Suspended Solids ◽

Oxidation Process ◽

Residence Times ◽

Waste Waters ◽

Pulp Mills ◽

Air Oxidation ◽

Wet Air Oxidation ◽

Feed Concentration ◽

Oxidation Of Phenol ◽

Made In

Abstract The Wet Air Oxidation process was developed by F.J. Zimmermann for removing suspended solids from waste waters, notably waste water from pulp mills. The basic idea behind the process is to combine the waste stream and air under suitable conditions so that liquid water is present. In theory waste organic is oxidized to CO2 and water, and thus removed by conversion to a harmless gas. In practice there are problems with incomplete combustion and tar formation especially in the oxidation of phenol. This project was undertaken to try and resolve these problems. Furthermore, specifications in the literature are for mixed reactors, which have financial disadvantages due to mixer sealing problems. This study is part 1 of a two part study to investigate unmixed reactors for the job of Wet Air Oxidation. The study was made in an unmixed reactor at temperatures of 200 and 250°C Pressure was varied from 800 to 2200 psi, and residence times from 0.25 to 2 hours. Phenol feed concentration was either 1400 or 3000 mg/L for all runs. Conversions of over 99% were achieved for conditions at the highest pressure and either temperature.

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