(159c) The Potential Use of Solar Photocatalytic Oxidation for Removal of  Emerging Pharmaceuticals from Effluent of Wastewater Treatment Plant:  a Pilot Plant  Study

Incident presence of what is called emerging contaminates(ECs) such as pharmaceuticals, pesticide in drinking water and wastewater have raised a lot of concern regarding the performance of the used conventional treatment processes. It was reported that the main reason for the presence of these ECs is related to the continual release of these contaminates into this eco-system from different point sources. ECs are considered non-biodegradable, and consequently it is expected that their concentration in the environment will continue to increase unless it is effectively treated and eliminated. Reasonable concentration of these contaminates have been detected in secondary treatment effluents of wastewater treatment plants (WWTPs). Contamination of groundwater with ECs was reported from different sources. Thus, there is a big need for an effective and cheap post-treatment to remove ECs from wastewater before discharge to the environment.

ECs can be effectively removed from water solution using different treatment processes such as activated carbon, nano-filtration and reverse osmosis. However, the cost associated with these treatment alternatives limits their applicability. Advanced oxidation processes (AOPs), on other hand, can be employed as an effective and promising technology for the removal of any traces of ECs from water and wastewater.. AOPs which based on the production of highly oxidative radicals are considered as destructive processes. These processes have the capacity to mineralize different contaminates from wastewater in a short period of time. The high cost associated with the use of AOTs (reagent and UV-light) limit their applicability and use in different treatment processes.

Most recently, solar advanced oxidation processes were successful applied for the treatment of different recalcitrant present in water and wastewater. The use of solar irradiation as photons source reduces the cost of AOPs and makes them a suitable treatment options. In the present study the solar oxidation of four groups of pharmaceuticals (antibiotics, estrogens, acidic, and neutral), commonly detected as emerging contaminants, were treated by different solar-driven photochemical processes including solar -photolysis, solar-photocatalytic oxidation using Fe(III) or TiO₂, solar based photo-Fenton reaction, and solar-photocatalytic reaction combined with ozonations. Results showed that Solar-photolysis solar-photocatalytic oxidation using Fe (III) are not effective for the complete removal of the selected contaminants, on other hand solar-photocatalytic oxidation using TiO₂, solar based photo-Fenton reaction showed significant removal efficiencies, high mineralization rate and produced final solution with lower toxicity if compared with original solution. Solar-photocatalytic reaction combined with ozonations considerably enhanced the pharmaceuticals removal efficiencies and decrease the acute toxicity of the treated solution