Enhancement of olive mill wastewater biodegradation by homogeneous and heterogeneous photocatalytic oxidation.

Olive mills wastewater (OMW) is characterized by its high organic content and refractory compounds. In this study, an advanced technology for the treatment of the recalcitrant contaminants of OMW has been investigated. The technique used was either photo-Fenton as homogeneous photocatalytic oxidation or UV/semi-conductor catalyst (such as TiO(2), ZrO(2) and FAZA) as heterogeneous photocatalytic oxidation for treatment of OMW. For both the processes, the effect of irradiation time, amounts of photocatalysts and semi-conductors, and initial concentration of hydrogen peroxide has been studied. At the optimum conditions, photo-Fenton process achieved COD, TOC, lignin (total phenolic compounds) and total suspended solids (TSSs) removal values of 87%, 84%, 97.44% and 98.31%, respectively. The corresponding values for UV/TiO(2) were 68.8%, 67.3%, 40.19% and 48.9%, respectively, after 80 min irradiation time. The biodegradability expressed by BOD(5)/COD ratio for treated wastewater was ranged from 0.66 to 0.8 compared to 0.19 for raw wastewater indicating enhancement of biodegradation.

Integrated treatment of olive mill wastewater (OMW) by the combination of Fenton's reaction and anaerobic treatment.

The use of an integrated treatment scheme consisting of wet hydrogen peroxide catalytic oxidation (WHPCO) followed by two-stage upflow anaerobic sludge blanket (UASB) reactor (10l each) for the treatment of olive mill wastewater was the subject of this study. The diluted wastewater (1:1) was pre-treated using Fenton's reaction. Optimum operating conditions namely, pH, H(2)O(2) dose, Fe(+2), COD:H(2)O(2) ratio and Fe(+2):H(2)O(2) ratio were determined. The UASB reactor was fed continuously with the pre-treated wastewater. The hydraulic retention time was kept constant at 48h (24h for each stage). The conventional parameters such as COD, BOD, TOC, TKN, TP, TSS, oil and grease, and total phenols were determined. The concentrations of polyphenolic compounds in raw wastewater and effluents of each treatment step were measured using HPLC. The results indicated a good quality final effluent. Residual concentrations of individual organic compounds ranged from 0.432 mg l(-1) for rho-hydroxy-benzaldhyde to 3.273 mg l(-1) for cinnamic acid.

Fenton's peroxidation and coagulation processes for the treatment of combined industrial and domestic wastewater.

As a consequence of the population growth, major efforts have been made by the Egyptian government to construct new industrial areas. Tenth of Ramadan City is one of the most important industrial cities in Egypt. The wastewater generated from various industrial activities was highly contaminated with organic matters as indicated by COD (1750-3323 mg/L), TSS (900-3000 mg/L) and oil and grease (13.2-95.5 mg/L). All overall appraisals of the analytical data from the industrial wastewater indicate that pretreatment is required for all industrial sectors to achieve compliance with the Egyptian Environmental law which requires effective pretreatment of industrial wastewater prior to its discharge into public sewers. Treatability studies via conventional and Fenton processes have been investigated. The efficiency of conventional treatment methods led to 63% COD and 44% color removal by using FeCl(3) as coagulant. Various coagulant aids and powdered activated carbon (PAC) were added to 400mg/L FeCl(3) in order to enhance the removal of color. It was found that polyacrylamide polymer, bentonite and PAC increased the efficiency of the treatments where the color removal increased to 79%, by cationic polymer, 73% by anionic polymer, 84.5% by bentonite and 95% for 0.4 g/L PAC. Fenton process was investigated which under the operating conditions (pH 3.0+/-0.2, Fe(2+) dose=400 mg/L and H(2)O(2)=550 mg/L), color removal up to 100% and more than 90% of COD removal were achieved.