Solar photo-Fenton Process Research Articles

Decolorization of methylene blue using Fe(III)-citrate complex in a solar photo-Fenton process: impact of solar variability on process optimization.

This study investigates the solar photo-Fenton based decolorization of a cationic dye methylene blue (MB) at circumneutral pH conditions. Water-soluble Fe(III)-citrate complex was used as a source of Fe(II) during the reaction by ligand-to-metal charge transfer under solar irradiation, and consequently, for the production of hydroxyl radicals. Solar decolorization of methylene blue was studied in sunny as well as cloudy weather, and further optimized using response surface methodology and Box-Behnken statistical experimental design. In this model, Fe(III) dose, citrate ion dose, and initial pH of the solution were used as independent parameters, and percentage decolorization of MB was used as a response. Better decolorization of MB was observed in sunny weather as compared to cloudy weather. A particular combination of parameters, i.e. pH of 7, Fe(III) of 0.5 mM, and citrate ion concentration of 10 mM, was found to achieve 89.19% and 51.22% decolorization in sunny and in cloudy weather respectively, which were the optimum/near-optimum performances for these weather conditions. Hence the process initiated with these parameters may potentially achieve better performance than any other parameter combination in all weathers, although the absolute removal would still depend on incident solar irradiation.

Use of sawdust as pretreatment of photo-Fenton process in the depuration of landfill leachate

A research of the depuration of landfill leachate using sawdust as activated carbon material to be applied in adsorption process as pretreatment of solar photo-Fenton and solar photo-Fenton + O3, was carried out. The activated sawdust shows very irregular shapes and pores, and a high capacity to remove ammonium (87.0%), iron (70.2%) and copper (61.1%). As well, it has the capacity to remove humic acid (18.3%), COD (33.7%) and colour (19.5%). Also, a removal of organic matter was obtained in terms of COD (76.4%), colour (74.9%), nitrate (50.0%), ammonium (12.8%) and humic acid (73.3%) due to the joint action of ozone and solar photo-Fenton process. The overall treatment (filtration, adsorption, photo-Fenton and photo-Fenton + ozone) carried out showed a very high removal of pollutants, with a reduction of COD, colour, ammonium and humic acid of 95.1%, 95.0%, 94.5% and 97.9%, respectively. With this enhancement in the landfill leachate (LL) quality, there is a reduction of toxicity, obtaining with the LL 50% diluted, a germination index for Lactuca sativa of 20% GI. This shows that the incorporation of sawdust is a useful pretreatment of photo-Fenton in the treatment of landfill leachate.

Degradation of xanthate in waters by hydrogen peroxide, fenton and simulated solar photo-fenton processes

This work reports the findings of a preliminary study of oxidative degradation of ethyl xanthate (EX) in aqueous solutions comparing hydrogen peroxide, the Fenton process, and photo-Fenton process driven by simulated solar radiation. Kinetic runs were carried out following a factorial design using a synthetic effluent with initial [EX]=100mg/L. H2O2 was dosed at the stoichiometric amount required for complete mineralization of EX. The variables studied were: initial pH: 5 and 9; [Fe2+]:[H2O2] molar ratio: 0:0 and 1:40; and irradiance: 0 and 30mW/cm2. An initial fast step breaks down more than 90% of the xanthate, forming intermediates that still contain unoxidized carbon and sulphur. Additional steps occur in which organic carbon and reduced sulphur from the intermediates may ultimately be converted into bicarbonate and sulphate. The progress of the reaction is indicated by reduction in TOC, gain in sulphate (SO4), and H2O2 consumption. Overall the optimum conditions for the breakdown of EX were those using the photo-Fenton process: initial pH=5; [Fe2+]:[H2O2] molar ratio=1:40; and irradiance=30mW/cm2. After 2h the best results were: xanthate breakdown=98.6%; TOC reduction=39.2%; SO4 generation=43.1%. The experiments were conducted batchwise and this led to partial mineralization of the xanthate's organic and sulphur contents. The statistical design using simulated solar radiation enabled us to conclude that tailings ponds could be used as treatment reactors, where their efficiency is enhanced by sunlight.

Advanced evaluation of landfill leachate treatments by low and high-resolution mass spectrometry focusing on microcontaminant removal

Conventional wastewater treatments are not usually effective in the remediation of specific landfill leachates due to their high content in toxic and recalcitrant compounds. Advanced and intensive treatments are needed for the decontamination and possible recycling of these effluents. Here, the combination of advanced oxidation processes (solar photo-Fenton) and an aerobic biological reactor have been applied to treat urban landfill leachates. The effectiveness of the proposed treatment line was also evaluated considering the removal of organic microcontaminants (OMCs) identified in the different phases, which is an innovative practice. The analytical strategy included: (i) a target approach (115 analytes) by liquid chromatography-mass spectrometry (LC–MS/MS); and two suspect approaches using (ii) LC-high-resolution MS (database with >1300 compounds) and (iii) gas-chromatography-MS (database with >900 compounds). OMCs on the treated landfill leachate was reduced up to 94% of the initial concentration. 8 target compounds (mainly pharmaceuticals) out of 115 target analytes represented 85% of the OMC concentration in the raw leachate: cotinine, diclofenac, gabapentin, ketoprofen, lidocaine, mecoprop, nicotine and trigonelline. 3 non-previously reported OMCs were confirmed: di-n-nonyl phthalate, o-phenylphenol and tonalide. Leachate partially oxidized by solar photo-Fenton process can be successfully incorporated to biological systems to complete the treatment by means of specifically adapted biomass.

Effect of liquid depth on microcontaminant removal by solar photo-Fenton with Fe(III):EDDS at neutral pH in high salinity wastewater.

In arid Mediterranean countries, such as Tunisia, wastewater often has high salinity, being an obstacle to the elimination of microcontaminants for the reuse of water in agriculture. In this paper, the photo-Fenton process in raceway pond reactors (RPRs) has been successfully applied to a simulated secondary effluent from a Tunisian urban wastewater treatment plant (WWTP), with high chloride load. A mixture of three contaminants of emerging concern (CECs) was used as model pollutants at 50 μg/L each (one antibiotic, sulfamethoxazole and two pesticides, pyrimicarb and imidacloprid). All the assays were conducted at neutral pH with 0.1 mM Fe(III):EDDS at 1:1 molar ratio. The effect of hydrogen peroxide initial concentration (20, 30, and 90 mg/L) on microcontaminant removal was studied. Different liquid depths (5 and 15 cm) were selected to assess the relationship between the microcontaminant removal and the volumetric rate of photon absorption (VRPA). Although the reaction rate was initially photo-limited, after a short reaction time of 15 min, the final yield (≈ 80% of CEC removal) was limited by the photo-degradation of the Fe(III):EDDS complex and excess H2O2 was found at all concentrations used. Therefore, treatment times below 15 min should be used. The treatment capacity was three times higher when the liquid depth was increased from 5 to 15 cm. For the first time, these results show that the operation of a 15 cm-deep RPR in continuous flow mode would be suitable for large-scale implementation of the solar photo-Fenton process.

Environmental impacts of an advanced oxidation process as tertiary treatment in a wastewater treatment plant

Due to global water scarcity, the use of reclaimed wastewater for crop irrigation is required; however, if the wastewater treatment is inadequate, it can be a source of environmental pollution. In order to improve wastewater reclamation, advanced oxidation processes (AOPs) have been tested. At full scale, ozonation is one such process that effectively removes micropollutants, despite its high-energy consumption. At pilot scale, other technologies such as the solar photo-Fenton process are being developed. This process is under consideration as a sustainable technology because it uses sunlight as a source of radiation. However, there is little information available on its environmental performance. In this work, we perform a comparative analysis between the ozonation and the photo-Fenton process as tertiary wastewater treatment processes used to reclaim wastewater for agricultural irrigation. We apply the Life Cycle Assessment (LCA) methodology for quantifying environmental impacts with ReCiPe and USEtox as life cycle impact assessment (LCIA) methods. The results show that both tertiary treatment options reduce water stress locally. Ozonation has a better overall environmental performance compared to the photo-Fenton process because the environmental impact of the required ozone is smaller than of the reactants involved in the solar photo-Fenton. Moreover, the first can be operated both day and night, and therefore needs no additional storage for collecting the nightly secondary effluent, and thus has lower infrastructure related impacts. Additionally, when the solar photo-Fenton process operates at an acidic pH, there are environmental drawbacks related to the pH adjustment, which consumes a large amount of acid thus liberating CO2. Finally, the environmental impacts associated with the discharge of micropollutants to soil through the use of reclaimed water are very small compared to the other impacts generated by the treatment. However, due to the current LCIA method limitations of micropollutant impact assessment, these are subject to major uncertainty.

Efficiency of Combined Processes Coagulation/Solar Photo Fenton in the Treatment of Landfill Leachate

The combined coagulation-solar photo Fenton treatment of leachate from the sanitary landfill located in Atlantico-Colombia was investigated. Firstly, the efficiency of two alternative combined treatments for the reduction of chemical oxygen demand in leachate was assessed, coagulation with poly-aluminum chloride followed by solar photo-Fenton process (Treatment 1) and coagulation with FeCl3·6H2O followed by ferrioxalate-induced solar photo-Fenton process (Treatment 2). Afterwards, treatments 1 and 2 were compared with the treatment currently used in the sanitary landfill (only coagulation with poly-aluminum chloride), in terms of efficiency and costs. An optimization study of alternative treatments was performed combining central-composite experimental design and response surface methodology. The optimum conditions resulted in a chemical oxygen demand reduction of 73 % and 80 % for Treatment 1 and 2, respectively. Both alternative treatments for the leachate are more efficient than the treatment currently used in the sanitary landfill (chemical oxygen demand reduction of 20 %). In terms of costs, treatment 1 would be the most competitive to implement in the sanitary landfill, since this would have an increase of 13.3 % in the total unitary cost compared to an increase of 39.5 % of treatment 2.

Total dissolved iron and hydrogen peroxide determination using the PhotoMetrixPRO application: A portable colorimetric analysis tool for controlling important conditions in the solar photo-Fenton process.

The use of the solar photo-Fenton process for water treatment requires monitoring of the main conditions, especially the total dissolved iron concentration and the consumption of hydrogen peroxide. In this study, a new methodology using the PhotoMetrixPRO application was validated for rapid monitoring of total dissolved iron and hydrogen peroxide concentrations, and was tested in the solar photo-Fenton process. A comparison was made between the results obtained using a reference spectrophotometric method and the PhotoMetrixPRO application employing a portable device. Both methods were validated in terms of linearity, sensitivity, precision, robustness, and matrix effects. The degree of dispersion between the series of measurements obtained using UV-vis and portable device tool was low and was in compliance with the established Brazilian and ICH validation criteria. Additionally, PhotoMetrixPRO enabled the use of a smaller sample volume. The total volume generated of each sample is 1 mL, reducing 6 and 10 times the wastes produced in different validated methods. These results evidencing that the miniaturization can provide positive advantages in terms of simplicity, cost effectiveness, and less environmental impact. PhotoMetrixPRO offers significant advantages including rapid analysis, smaller sample volumes, and greater portability and accessibility.

Effect of solar photo-Fenton process in raceway pond reactors at neutral pH on antibiotic resistance determinants in secondary treated urban wastewater.

Solar photo-Fenton process in raceway pond reactors was investigated at neutral pH as a sustainable tertiary treatment of real urban wastewater. In particular, the effect on antibiotic resistance determinants was evaluated. An effective inactivation of different wild bacterial populations was achieved considering total and cefotaxime resistant bacteria. The detection limit (1 CFU mL-1) was achieved in the range 80-100 min (5.4-6.7 kJ L-1 of cumulative solar energy required) for Total Coliforms (TC) (40-60 min for resistant TC, 4.3-5.2 kJ L-1), 60-80 min (4.5-5.4 kJ L-1) for Escherichia coli (E. coli) (40 min for resistant E. coli, 4.1-4.7 kJ L-1) and 40-60 min (3.9-4.5 kJ L-1) for Enterococcus sp. (Entero) (30-40 min for resistant Entero, 3.2-3.8 kJ L-1) with 20 mg L-1 Fe2+ and 50 mg L-1 H2O2. Under these mild oxidation conditions, 7 out of the 10 detected antibiotics were effectively removed (60-100%). As the removal of antibiotic resistance genes (ARGs) is of concern, no conclusive results were obtained, as sulfonamide resistance gene was reduced to some extent (relative abundance <1), meanwhile class 1 integron intI1 and ß-lactam resistance genes were not affected. Accordingly, more research and likely more intensive oxidative conditions are needed for an efficient ARGs removal.

On the design and operation of solar photo-Fenton open reactors for the removal of contaminants of emerging concern from WWTP effluents at neutral pH

This work presents for the first time a tool for the design of continuous raceway pond reactors to remove contaminants of emerging concern (CECs) from WWTP secondary effluents by solar photo-Fenton process at neutral pH. The effects of the hydraulic residence time (HRT) and the liquid depth on the treatment capacity were studied, the availability of solar UV radiation being the main environmental variable. Treatment capacities as high as 1800 and 9000 L m−2 d-1 were estimated for 70% CEC removal in winter and summer, respectively. To this aim, the performance of a kinetic model of the photo-Fenton process developed with Fe3+-EDDS was updated to predict CEC removal in effluents collected from different WWTPs. To reach a goal of CEC elimination, the treatment capacity can be maximized as a function of HRT and liquid depth, and consequently the reactor surface area is calculated to treat a given flow rate.

Photochemical Degradation of Micropollutants in Aqueous Media

Natural sunlight was employed to enhance degradation of micropollutants in a Fenton-like oxidative system involving persulfate as the oxidant and ferrous iron (Fe(II)) as the catalyst Fe2+/S2O82−/Solar. Experiments were carried out in a bench-scale compound parabolic collector (CPC) and a batch photoreactor. The micropollutants tested were p-chlorophenol, atrazine, and triclosan. The reaction rates and degree of micropollutant degradation increased in the order: {Solar} < {S2O82−/Solar} < {Fe2+/S2O82−} << {Fe2+/S2O82−/Solar}. It was proven that photocatalytic oxidation activated by solar radiation leads not only to complete degradation of micropollutants, but also to substantial drops in levels of total organic carbon in the solution (i.e. leads to mineralization). Based on the results, a method of deep degradation of toxic organic pollutants based on the solar photo-Fenton process Fe2+/S2O82−/Solar was suggested.

Kinetic assessment of antibiotic resistant bacteria inactivation by solar photo-Fenton in batch and continuous flow mode for wastewater reuse

The presence of antibiotic resistant bacteria in municipal wastewater treatment plants represents a real risk to human health. For the first time, this paper shows that the inactivation rate of cefotaxime resistant bacteria is the same as total bacteria when secondary effluents are treated by the solar photo-Fenton process. To obtain this result, an exhaustive and comparative kinetic study on the inactivation of both total and cefotaxime resistant bacteria (Total coliform, Escherichia coli and Enterococcus sp) was carried out, taking into account the effects of the main operation conditions, such as solar irradiance and iron concentration, and operation mode (batch and continuous). In all the operation conditions studied, no significant differences were found between the first order inactivation rate constants, ki, of total and cefotaxime resistant bacteria. Additionally, ki increased with solar irradiance and iron concentration. As for the effect of the operation mode, the main finding of this work is much quicker inactivation in continuous flow mode than in batch mode, pointing out its potential application at large scale. The best continuous operation condition to inactivate the bacteria to the detection limit (1 CFU mL−1), was at 22.4 min of hydraulic residence time with 5 mg Fe2+ L−1 and 30 mg H2O2·L−1. This treatment time is approximately a third of that reported in batch mode. The efficiency, in terms of figure of merits, of the continuous flow operation was 2.7 m2 of solar collector area to reduce one log of E. coli concentration per m3 of treated water and per hour, in comparison with 2137 m2 calculated for batch operation under the same solar UVA irradiance, 30 W m−2. This paper encourages research into continuous solar disinfection processes due to its enhanced efficiency with regard to the commonly used batch wise operation and shows that efficient removal of total bacteria ensures the removal of antibiotic resistant bacteria.

Combining Chemical and Photo-Fenton Solar Coagulation Processes in the Treatment of Real Wastewater from Paint Industry

In this work are presented and discussed the results related to the obtaining of the best conditions for the treatment of a real paint wastewater by combining the chemical coagulation methods and solar photo-Fenton process. The best conditions for the coagulation-flocculation process involved the use of 8 mL of chemical coagulant (ferric chloride) for every 1.0 L of wastewater. At this condition, total removal of turbidity and color (visual inspection) of the wastewater were achieved. For the solar photo-Fenton process, the concentration of Fe 2+ and H 2 O 2 at 105 mg L -1 and 2.0 g L -1 , respectively, resulted in the complete removal of organic matter and odor (olfactory perception). Therefore, the combined use of these techniques in the treatment of the real paint wastewater presented quite relevant results from the environmental standpoint, as evidenced by the reduction/elimination of important environmental parameters, with the real possibility of disposal and/or reuse proposals of treated water. DOI: http://dx.doi.org/10.17807/orbital.v11i2.1365

Feasibility analysis of homogenizer coupled solar photo Fenton process for waste activated sludge reduction

In this study, an attempt has been made to reduce the sludge using novel homogenizer coupled solar photo Fenton (HPF) process. At an optimum pH of 3 and Fe2+ to H2O2 dosage of 1:6, PF process yielded 63.7% solids reduction at a time interval of 45 min. Coupling of homogenizers with photo Fenton (PF) process effectively enhanced treatment efficiency. When homogenizer (specific energy - 1150.694 kJ/kg TS) was coupled with PF, a sharp increase in solid reduction 73.5% and decrease in reaction time (20 min) were observed. Cost benefit analysis revealed the efficiency of HPF process and achieved a net cost of 15.59 USD whereas PF achieved a negative net cost of −82.69 USD. Based on the above study it can be concluded that coupling of homogenizers with PF not only increased its efficiency but also make it field applicable.

Assessment of solar raceway pond reactors for removal of contaminants of emerging concern by photo-Fenton at circumneutral pH from very different municipal wastewater effluents

This paper presents for the first time the treatment of contaminants of emerging concern (CECs) in a systematic study in different municipal wastewater treatment plants (MWWTPs) of the Mediterranean area, more than 1000 km away. Solar photo-Fenton process at neutral pH with Fe3+-EDDS has been demonstrated to be very efficient under controlled conditions and must be validated in realistic and variable conditions such as real MWWTP effluents of different composition. To this end, CEC removal was studied in effluents from 5 treatment plants in the Mediterranean area of Spain, the inorganic and organic composition varying in the range 161–641 mg L−1 (sulfate), 133–538 mg L−1 (chloride) and 10–20 mg L−1 (dissolved organic carbon). More than 45 CECs were quantified in MWW and results showed that the effect on CEC elimination of the concentration of anions and organic matter was interfered by the nature of the organic matter. However, origin and composition of MWW was not critic for attaining >80% degradation of CECs after 15 min of reaction. Moreover, conventional anions (sulfate, chloride) had a positive effect on CEC degradation rate. This paper demonstrates the consistency and predictability of the solar photo-Fenton process at circumneutral pH for treating CECs in simple and cheap photoreactors.

Continuous flow disinfection of WWTP secondary effluents by solar photo-Fenton at neutral pH in raceway pond reactors at pilot plant scale

The feasibility of low cost reactors such as raceway pond reactors (RPRs) for micropollutant removal as well as pathogen inactivation has recently been reported. This study presents, for the first time, the inactivation of Total Coliforms, Escherichia coli and Enterococcus sp. in WWTP secondary effluents by the solar photo-Fenton process in continuous flow at neutral pH in open reactors. Firstly, indoor assays were carried out with three hydraulic residence times (HRTs), 15, 30 and 60 min under simulated solar radiation of 30 W m−2, 5 cm liquid depth, 20 mg Fe2+ L−1 and 50 mg H2O2 L−1. At 60 and 30 min of HRT, wastewater disinfection below 1 CFU mL−1 was achieved at steady state for the three microbial groups selected. Nevertheless, at 15 min of HRT only 1-log inactivation was obtained. Taking into account the results obtained at laboratory scale, the best HRTs (60 and 30 min) were tested outdoors in 5 cm-deep RPRs in both summer and winter. The start-up began with a batch operation for 120 min with 20 mg Fe2+ L−1 and 50 mg H2O2 L−1, followed by continuous operation over three consecutive days with 20 mg Fe2+ L−1 and 30 mg H2O2 L−1 to avoid large excess of hydrogen peroxide in steady state. Bacterial inactivation results showed 30 min of HRT to be the most efficient operation condition capable of producing 305 m3 m−2 year−1 of disinfected water while complying with the Spanish Law (RD 1620/2007) for water reuse. Additionally, a reduction in iron supply ranging from 10 to 2.5 mg L−1 in continuous mode with 30 mg H2O2 L−1 was evaluated. Efficient microorganism inactivation was reached for 10 and 5 mg Fe2+ L−1, thus reducing the iron consumption at steady state four-fold. This research opens up a new line of research on the optimisation of wastewater disinfection by large-scale solar photo-Fenton.

Degradation of pharmaceuticals in different water matrices by a solar homo/heterogeneous photo-Fenton process over modified alginate spheres.

A solar homo/heterogeneous photo-Fenton process using five materials (Fe(II), Fe(III), mining waste, Fe(II)/mining waste, and Fe(III)/mining waste) supported on sodium alginate was used as a strategy to iron dosage for the degradation of eight pharmaceuticals in three different water matrices (distilled water, simulated wastewater, and hospital wastewater). Experiments were carried out in a photoreactor with a capacity of 1L, using 3g of iron-alginate spheres and an initial hydrogen peroxide concentration of 25mgL-1, at pH 5.0. All the materials prepared were characterized by different techniques. The Fe(III)-alginate spheres presented the best pharmaceutical degradation after a treatment time of 116min. Nineteen transformation products generated during the solar photo-Fenton process were identified by liquid chromatography coupled to quadrupole time-of-flight mass spectrometry, using a purpose-built database developed for detecting these transformation products. Finally, the transformation products identified were classified according to their toxicity and predicted biodegradability.

Degradation of amoxicillin by Fenton and Fenton-integrated hybrid oxidation processes

The present study aims to investigate the degradation of amoxicillin (AMX) using the Fenton process and hybrid Fenton-like processes such as photo-Fenton, solar photo-Fenton, sono-Fenton, and sono-photo-Fenton. The effect of ferrous ions (Fe2+), hydrogen peroxide (H2O2), and pH was evaluated. Complete degradation was achieved within 12 min of reaction time under the optimized conditions of Fe2+- 30 mg/l, H2O2 – 375 mg/l, and pH – 3.0 during Fenton’s process. Efficiency towards degradation of AMX was enhanced when the Fenton’s process was coupled with UV- light illumination, solar light illumination, and UV light-Ultrasound treatment. Complete degradation was observed within 3.5 min and 9 min during the photo-Fenton and solar photo-Fenton process, respectively. The sono-Fenton process takes a longer time to degrade AMX than other processes while sono-photo-Fenton process degrades AMX within 6 min. The reason for a reduced rate of degradation of AMX in the sono-Fenton process may be attributed to the competition of ultrasound and Fenton for H2O2, which ultimately decreases Fenton reagent in the process. The study concluded that the Fenton process coupled with other UV/solar light is more efficient than the stand-alone Fenton process towards degradation of AMX.

Multi-response optimisation of the solar photo-Fenton process for landfill leachate post-treatment

Multi-response optimisation of the solar photo-Fenton process for landfill leachate post-treatment

Solar photo-Fenton oxidation followed by adsorption on activated carbon for the minimisation of antibiotic resistance determinants and toxicity present in urban wastewater

This work evaluated the removal of a mixture of antibiotics from urban wastewater, by a combined process consisting of solar photo-Fenton (SPF) followed by granular activated carbon (GAC). The effects of the SPF process were investigated at a toxicological, microbiological and genomic level, using species of plants and aquatic organisms, bacteria, antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). The results demonstrated that SPF could completely degrade antibiotics present in two types of effluent deriving from a conventional activated sludge system (CAS) and a membrane bioreactor (MBR), operated at the optimum oxidant dose ([H2O2]CAS = 100 mg/L; [H2O2]MBR = 50 mg/L) and illumination time (tCAS = 115 min; tMBR = 111 min) at acidic pH (2.8–2.9). Moreover, total disinfection was achieved by the SPF process, as cultivable bacteria, including ARB, were inactivated after 60 min of treatment, disabling also the bacterial regrowth after 24 h of storage of the treated effluent. Furthermore, SPF was shown to be effective in degrading the cellular DNA of the effluent, which was reduced to the detection limit after 60 min of treatment in both effluents. The abundance of 16S rRNA was found to be preferentially decreased by the SPF in the MBR-treated effluent (8 folds) compared to the CAS-treated effluent (7.4 folds). The abundance of blaOXA, blaCTX-M, qnrS, sul1, and tetM genes was decreased to the limit of quantification after 60 min of SPF treatment in both effluents. However, the SPF treated flow resulted in increased toxicity, probably due to the oxidation of the dissolved effluent organic matter of the wastewater leading to the formation of toxic products. Therefore, SPF-treated samples collected at different time intervals (30, 60, 90, 120, and 180 min) were subjected to adsorption onto GAC (500 mg/L), and the removal of both the toxicity and the residual antibiotics remaining after SPF, was explored. The combined processes (30 min SPF; 15 min GAC) provided almost complete removal of toxicity and elimination of antibiotics, ensuring wastewater decontamination.