Raceway Pond Reactor Research Articles

Innovative waste activated sludge pre-treatment using a raceway pond Reactor: Integration of Low-Temperature and solar radiation

A novel pre-treatment, using a raceway pond reactor (RPR), combining the use of thermal and solar effects, was applied to enhance anaerobic digestion (AD) of waste activated sludge (WAS) from an urban wastewater treatment plant. Thermal pre-treatment at 25, 50, 60 and 70 °C was carried out for 5 h with (under distinct values of UV radiant power) and without solar radiation and varying WAS depth in the RPR (5 or 7 cm). Higher temperatures (60 and 70 °C) and longer treatment times (3 to 5 h) resulted in increased disintegration of bacterial cells. The WAS pre-treatment significantly (p-value ≤ 0.001) boosted soluble chemical oxygen demand (SCOD) levels, achieving a disintegration degree of 19.7 % at 70 °C with solar radiation (7.2 kJUV L-1WAS), which corresponds to a 15-fold increase of SCOD, compared to the baseline at 25 °C without radiation. Moreover, at the highest temperature (70 °C), there was a significant SCOD increase (p-value ≤ 0.05) of approximately 400 mgO2 L-1 in the presence of solar radiation. This synergetic effect between temperature and solar radiation caused cell damage, membrane rupture, and release of cellular content, shifting extracellular polymeric substances from tightly bound to loosely bound and soluble fractions, consequently improving methane production. Methane production increased by 131 % compared to the control (25 °C) under 70 °C and after 7.2 kJUV L-1WAS, indicating a positive impact on WAS hydrolysis. The technology adopted in this work fosters methane production predominantly using renewable solar energy without chemical residues. This is the first report on RPR for WAS pre-treatment, combining mild temperature and solar radiation.

Kinetic model implementation in raceway pond reactors with hydrodynamic and radiation fields

Vertical mixing plays a critical role in solar-driven processes using raceway pond reactors (RPRs). However, incorporating the time history of radiation for each fluid element is still an open issue. This work aims to develop an effective methodology using Computational Fluid Dynamics (CFD) tools that couples hydrodynamics and radiation fields into kinetic models of biomass growth or cell lysis enhanced from radiation. First, three methodologies to assess vertical mixing were investigated. It was found that, under typical RPR flow conditions, the velocity in the direction of solar light incidence can maintain particles in constant motion and a near-homogenous particle distribution. In addition, two RPR applications were studied regarding radiation influence analysis: the production of microalgae and an innovative approach for waste activated sludge (WAS) pre-treatment, fostering biogas production. Regarding microalgae production, coupling the biokinetic models with CFD data enables the development of a cost-effective computational methodology to describe the growth of microalgae cultures accounting for hydrodynamics and radiation fields. This work was successful in introducing hydrodynamics and radiation conditions in models to design and optimise RPRs. Reduced geometries based in 2D and Periodic Boundary Conditions were used for CFD simulations to make it feasible for RPRs design purposes.

Assessment of the Raceway Pond Reactor for Degradation of Methylene Blue Dye in Different Types of Water: A Systematic Kinetics Study under Natural Solar Light

Assessment of the Raceway Pond Reactor for Degradation of Methylene Blue Dye in Different Types of Water: A Systematic Kinetics Study under Natural Solar Light

Enhancing immobilized Chlorella vulgaris growth with novel buoyant barium alginate bubble beads

Microalgae immobilization in alginate beads shows promise for biomass production and water pollution control. However, carrier instability and mass transfer limitations are challenges. This study introduces buoyant barium alginate bubble beads (BABB), which offer exceptional stability and enhance Chlorella vulgaris growth. In just 12 days, compared to traditional calcium alginate beads, BABB achieved a 20 % biomass increase while minimizing cell leakage and simplifying harvesting. BABB optimization involved co-immobilization with BG-11 medium, enrichment of CO2 in internal bubbles, and the integration of Fe nanoparticles (FeNPs). In the open raceway pond reactor, these optimizations resulted in a 39 % increase in biomass over 7 days compared to the unoptimized setup in closed flasks. Furthermore, enhancements in pigment and organic matter production were observed, along with improved removal of ammonia nitrogen and phosphate. These results highlight the overall advantages of BABB for microalgae immobilization, offering a scientific foundation for their effective utilization.

Micropollutant elimination by sustainable technologies: Coupling activated carbon with solar photo-Fenton as pre-oxydation step

This study evaluates the effectiveness of coupling solar photo-Fenton (SPF) with granular activated carbon (GAC) filtration to remove three selected micropollutants (benzotriazole, carbamazepine and diclofenac) from municipal wastewater treatment plant (WWTP) effluent. SPF was first studied stand-alone at natural pH with simulated and real irradiation in raceway pond reactors (RPR) in different water matrices. The scenario with the poorest removal was the use of real WWTP effluent as water matrix; the removal achieved was 25 % of benzotriazole, 57 % of carbamazepine and up to 80 % of diclofenac (6 mg L−1 of iron, 40 mg L−1 of H2O2, 15 cm depth, 0.49 kJ L−1). In the second phase, fresh and regenerated GAC were studied in different water matrices, showing that the complex matrices had a higher influence on the regenerated GAC. Thus, the breakthrough of regenerated GAC was achieved quicker than fresh GAC. The aim of the work was to extend the GAC lifetime by a pre-oxidation process; thus, SPF was applied for 5 minutes (0.05–0.08 kJ L−1) as a first step. GAC lifetime was extended between 2 and 12 times thanks to the pre-treatment by SPF, equaling the lifetime of the regenerated GAC to the fresh one in the more complex matrix.

Comprehensive evaluation of a novel pilot-scale UVA-LED photoreactor for water treatment applications: Characterization, catalytic efficiency, energy performance and economic viability

A comprehensive assessment was conducted on a novel pilot plant employing a tubular photo-reactor configuration integrated with UVA-LED technology for advanced municipal wastewater treatment applications. The plant consists of eight UVA-LED strips (150 LEDs/strip, 348–400 nm with peak emission at 370 nm) achieving a maximum irradiance of 28.1 W/m2 at 100 % power of the LED, symmetrically distributed across two borosilicate tubes. The iron concentration (0.025–0.100 mM) and UVA-LED irradiance (1.4–28.1 W/m2) combined effect on the photo-Fenton process efficiency was thoroughly examined in synthetic tap water and synthetic municipal wastewater treatment plant (MWWTP) secondary effluent using sulfamethoxazole as model microcontaminant. In general, an LED intensity threshold from which process efficiency reaches a plateau maximum value was found. The determination of the electrical energy per order (EEO) showed higher energy efficiencies as LED intensity decreases, iron concentration increases, and the water matrix is simpler. The lowest EEO obtained was 0.009 kWh/m3·order for 0.10 mM iron concentration in synthetic MWWTP secondary effluent at 5 % LED intensity. The economic study revealed that the weight of operating costs is more significant than the weight of investment costs, regardless of the selected operating conditions. Working with an iron concentration of 0.10 mM helps reduce the total costs, while operating either under excess LED intensity or insufficient LED intensity negatively impacts the total treatment cost. The lowest treatment cost (0.19 €/m3) was obtained with 0.10 mM iron concentration at only 10 % LED intensity. A comparison with the same process driven by natural solar radiation in a raceway pond reactor demonstrated the feasibility of the novel photo-reactor design in terms of treatment cost.

Experimental study of wastewater micropollutant removal by solar photo‐Fenton using a virtual lab

AbstractNew technologies are providing opportunities for the design of novel educational methodologies. Virtual laboratories can simulate real conditions, thus reducing the workload of teachers and students, and removing the costs associated with laboratory or pilot plant tests. The present work describes the creation of a virtual and interactive lab using the Easy JavaScript Simulation (EJsS) 6.0 tool. The solar photo‐Fenton process for the degradation of the Acetamiprid pesticide (ACTM) as a micropollutant model in wastewater was implemented in discontinuous mode in a stirred tank reactor (STR) and in continuous mode in a raceway pond reactor (RPR). The objective was to achieve a virtual tool that would allow easy, intuitive connection to different devices (laptops, tablets, and smartphones), simplifying the difficulties related to teaching technology. This contribution details the design and implementation process of the model for its use as support material for theoretical classes. The virtual tool presented in this article is an example of how the EJsS platform can be used to teach dynamics systems in chemical engineering.

Exploring the scalability of solar-activated persulfate with iron-EDDS in raceway pond reactors for advanced wastewater treatment

In this study, the removal of microcontaminants (MCs) by the activation of persulfate (PS) with Fe(III)-EDDS under natural solar radiation in a low-cost raceway pond reactor (RPR) was investigated. The primary focus was to evaluate the effect of the Fe(III)-EDDS molar ratio, initial iron concentration, PS concentration, and initial pH on process performance while using sulfamethoxazole (SMX) and carbamazepine (CBZ) as model MCs. The investigation encompassed three different water matrices: natural water, synthetic municipal wastewater treatment plant (MWWTP) secondary effluent, and actual MWWTP secondary effluent. During experiments in natural water, it was found that 0.1 mM Fe(III) at a 1:2 molar ratio and 0.2 mM Fe(III) at a 1:1 molar ratio resulted in the most adequate operational conditions. Further experiments revealed a general decrease in process efficiency due to water matrix effects; however, this could be compensated by increasing the initial PS concentration and decreasing the initial operation pH. For example, the use of 0.2 mM Fe(III) at a 1:1 Fe(III):EDDS molar ratio, with 2 mM PS at pH 6, allowed for an 80% removal of the MCs sum in approximately 20 min, along with a significant decrease in chronic toxicity (Selenatrum Capricornutum) when working with actual waters. Nonetheless, the final experiment, focused on simultaneous MCs removal and wild bacteria inactivation in actual MWWTP secondary effluent, showed only a 1.6–1.8 log reduction of Escherichia coli, total coliforms, and Enterococcus faecalis. As such, further studies about the solar/Fe(III)-EDDS/PS process are needed to explore new strategies that improve its disinfection efficiency.

Simultaneous degradation of contaminants of emerging concern and disinfection by solar photoelectro-Fenton process at circumneutral pH in a solar electrochemical raceway pond reactor

Simultaneous contaminants of emerging concern (CECs) removal and wild microorganisms’ inactivation was evaluated by applying solar photoelectro-Fenton (SPEF) process in actual secondary effluent collected from a real municipal wastewater treatment plant (MWWTP). 20 L of a mixture of four CECs was used as model pollutants (200 μg/L of acetaminophen, caffeine, sulfamethazine, and sulfamethoxazole each one). The SPEF process was carried out on fully sunny days, at circumneutral pH using the complex Fe3+-EDDS, in a solar electrochemical – raceway pond reactor (SEC-RPR). Initially, the optimal conditions for CECs degradation were determined using a response surface model based on current density, iron complex concentration and Fe3+-EDDS addition time (to allow previous accumulation of H2O2) as model inputs. A current density of 24.6 mA/cm2, a Fe3+-EDDS complex concentration of 0.089 mM and 3.8 min of previous H2O2 accumulation were the resulting optimum conditions that were afterwards applied for the simultaneous degradation of the CECs synthetic mixture and wild microorganisms inactivation in actual secondary effluent. About 85% CECs removal and complete E. coli inactivation were achieved in 30 min, approximately, while E. faecalis and total coliforms could be inactivated under detection limit in 60 min and 75 min, respectively.

Continuous flow operation of solar photo-Fenton fused with NaOCl as a novel tertiary treatment

A novel strategy based on solar photo-Fenton mediated by ferric nitrilotriacetate (Fe3+-NTA) combined with NaOCl in continuous flow mode for wastewater reclamation has been studied. Escherichia coli (E. coli) inactivation attained ≥ 5 log10-units, meeting the most restrictive EU 2020/741 target (10 CFU/100 mL), and 75% of organic microcontaminant total load was removed. As a remarkable finding, trihalomethanes (THMs) concentration was insignificant, complying by far with the Italian legislation limit. To attain these results, first the effect of liquid depth on E. coli inactivation and imidacloprid (IMD) removal from spiked municipal effluents was evaluated in continuous flow pilot-scale raceway pond reactors at 60-min hydraulic residence time with low reagent concentrations (0.10 mM Fe3+-NTA, 0.73 mM H2O2 and 0.13 mM NaOCl). Disinfection was due to the bactericidal effect of chlorine. In contrast, liquid depth notably influenced microcontaminant removal, highlighting that operation at 10-cm liquid depth allows achieving treatment capacities higher than at 5 cm (16.50 vs 28.20 mg IMD/m2∙day). Next, the monitoring of THMs was carried out to evaluate the generation and degradation of disinfection by-products, along with the removal of actual microcontaminants. These promising results draw attention to the treatment potential and open the way for its commercial application.

Continuous solar photo-Fenton for wastewater reclamation in operational environment at demonstration scale

For the first time, a continuous flow solar photo-Fenton demonstration plant has been assessed for wastewater reclamation according to the EU 2020/741 regulation. The treated water qualities achieved under two operating strategies (acidic and neutral pH) in a 100-m2 raceway pond reactor were explored in terms of liquid depth, iron source, reagent concentrations, and hydraulic residence time over three consecutive days of operation. The results obtained at acidic pH showed removal percentages of contaminants of emerging concern (CECs) > 75% and water quality classes B, C and D according to EU regulation at both assessed operating conditions, with treatment capacities up to 1.92 m3 m-2 d-1. At neutral pH with ferric nitrilotriacetate (Fe3+-NTA), 50% of CEC removal and only water quality class D were achieved with the most oxidizing condition assessed, giving a treatment capacity of 0.80 m3 m-2 d-1. The treatment capacities obtained in this work, which have never been achieved with solar water treatments, demonstrate the potential of this technology for commercial-scale application.

FentonSims®: A novel interactive simulation tool for computational kinetics of microcontaminant removal by the solar photo-Fenton process

This work presents, for the first time, a simulation app for the mechanistic understanding of the solar photo-Fenton process applied to the removal of microcontaminants contained in wastewater treatment plant secondary effluents. FentonSims® incorporates three mechanistic kinetic models previously developed for the process at acidic and neutral pH with different iron chelators (nitrilotriacetic acid and ethylenediamine-N,N’-disuccinic acid). The end-user can simulate the operation of perfect mixing raceway pond reactors in batch and continuous mode as a function of environmental (UVA radiation and water liquid temperature) and operating conditions (hydraulic residence time, liquid depth and reagent concentrations). Furthermore, this tool allows the assessment of different levels of water contamination, and estimations for reagent conversion, microcontaminant removal yield and water treatment capacity are shown in the graphical user interface. Simulations are conducted in an intuitive and easy-to-use app, so no programming skills are required, and all data are saved, allowing the user to analyse a wide range of operating scenarios. Therefore, FentonSims® is a valuable didactic tool for graduate students and water treatment professionals interested in the applicability of the solar photo-Fenton process and its phenomenological understanding.

Ozonation Vs sequential solar driven processes as simultaneous tertiary and quaternary treatments of urban wastewater: A life cycle assessment comparison

Solar driven advanced oxidation processes (S-AOPs) have been successfully investigated in the last years as tertiary and quaternary treatment of urban wastewater for simultaneous inactivation of microorganisms and removal of contaminants of emerging concern (CECs), respectively. However, the lack of data about the comparison with consolidated technologies, including also the evaluation of their impact on the environment, has contributed to humper their application at full scale so far. In this study, the environmental impact of a new S-AOP, namely sequential treatment (ST) with sunlight/H2O2 and solar photo-Fenton (SPF) at neutral pH (using Ethylenediamine-N, N′-disuccinic acid (EDDS) as chelating agent) operated at pilot scale in a raceway pond reactor, was compared to a pilot scale ozonation (O3) treatment unit in terms of simultaneous bacteria inactivation and CECs removal, through a Life Cycle Assessment (LCA). Different urban wastewater treatment plant (UWWTP) sizes and scenarios (namely effluent disposal and reuse) were evaluated. While the reuse scenario resulted in a higher impact compared to the disposal scenario in the construction/deconstruction phase, due to the more stringent limits that resulted in longer treatment time and a higher consumption of raw materials, the positive impact on water resources saving compared to disposal makes the reuse scenario a more sustainable solution. Despite O3 disinfection by-products were taken into account, ST resulted in a higher toxicity to human health (0.27·10−9 DALYs Vs 2.11 10−9 DALYs, respectively) due to the higher residual concentration of the target CECs. However, it is noteworthy that both values are significantly lower than the acceptable DALYs value (≤10−6). Chemicals, energy, groundwater consumption and residual CECs can affect resources 1125 and 1874 times more for O3 treatment than for the ST, for disposal and reuse scenarios, respectively. The total impact of O3 on the human health was 13 and 19 times higher compared to ST, for disposal and reuse scenarios, respectively, due to the higher energy and chemical consumption. According to the LCA results, ST resulted in a better overall environmental performance compared to O3 and it is a more sustainable and attractive solution in particular for small UWWTPs.

Landfill leachate treatment by a combination of a multiple plant hybrid constructed wetland system with a solar photoFenton process in a raceway pond reactor

The sustainable and green treatment of landfill leachate (LL), produced by municipal solid waste, represents one of the most relevant challenges in the integrated waste management systems. Accordingly, in this work a green solution was investigated by coupling an innovative hybrid constructed wetland (HCW) to a solar photo-Fenton (SPF) process. A multiple layers HCW pilot plant including different medium substrates (sand, solid compost and carriers) and plant species (Phragmites australis, Arundo donax and A. plinii) was designed. The HCW was functionalised with compost tea solution to simultaneously provide high nutrient content for plants and increase the microorganism biodiversity. Process efficiency was investigated using different real LLs (young and mature) in terms of chemical oxygen demand (COD), nitrogen compounds, chlorides and metals. Removals in the range 75–95% were observed for all the parameters after ten days of leachate recirculation in the pilot plant. Subsequently, the SPF process was carried out in a raceway pond reactor (RPR) as polishing step, significantly improving COD removal (further 49%). HCW combined with SPF in RPR would allow to meet the corresponding limits according to the final use/fate of the effluent by modulating the main parameters of the process.

A novel control system approach to enhance the efficiency of solar photo-Fenton microcontaminant removal in continuous flow raceway pond reactors

This work presents a control approach for the continuous flow operation of the solar photo-Fenton process in raceway pond reactors designed for micropollutant (MP) removal from urban wastewater treatment plant secondary effluents. The control system was designed using the mechanistic and semiempirical kinetic model of the photo-Fenton process at acidic pH developed and validated in previous work. Afterwards, a simulation study to demonstrate the viability of the control system was conducted under different operating conditions (hydraulic residence time and liquid depth) for solar irradiance and water temperature variation over the year. Two liquid depths (10 and 20 cm) and two hydraulic residence times (15 and 30 min) were selected as operating conditions to study the system performance for different MP removal control setpoints (70 % and 90 %). For 90 % MP removal setpoint, cost efficiency reductions of up to 21 % were reached, which denotes that the process efficiency is significantly influenced by the control setpoint. This is because highly demanding MP removal setpoints are achieved through high non-linear reagent consumption, resulting in low operating cost efficiencies of the process. On the other hand, cost efficiency improvements from 45 to 50 % were achieved when an 70 % MP removal setpoint was adopted, when comparing the manual operation of the process with the automatic mode. The presented results demonstrate not only the feasibility of implementing an automatic approach for the solar photo-Fenton process, but also the need for an optimised, efficient and controlled operation to upgrade its competitiveness versus conventional technologies.

Microcontaminant removal in solar pilot scale photoreactors with commercial iron nanoparticles obtained from olive mill wastewater

This study assessed removal of microcontaminants (MCs) from natural water (NW) using iron nanoparticles extracted from olive mill wastewater (ZVI-OMW), an agro-industrial waste product, combined with oxidants under natural solar radiation. The specific effects of corrosion, adsorption and solar photolysis, and of H2O2, S2O82-, carbonates and ZVI-OMW concentrations on treatment efficiency were also evaluated. Lab tests demonstrated that the combination of 1 mM S2O82- with NW and 1 mM ZVI-OMW was the best treatment option. Process performance was evaluated under these operating conditions in pilot-scale raceway pond reactors (RPR) at three liquid depths (5, 10 and 15 cm), as well as in a compound parabolic collector (CPC) photo-reactor. The time required to achieve 50% removal of a MC mixture (atrazine, carbendazim, imidacloprid and thiamethoxam, at 100 µg/L each) increased with liquid depth, resulting in 164, 224, and 250 min for 5, 10, and 15 cm, respectively. MC mass removal rate increased with liquid depth, achieving 50% MC removal in the CPC (1 mM ZVI-OMW) in 120 min. Doubling ZVI-OMW concentration was detrimental to process efficiency in both photoreactors due to light obstruction. Partial sedimentation of ZVI-OMW in the RPR suggests that the use of this type of reactor for heterogeneous photocatalysis could present problems for large-size operation.

Removal of contaminants of emerging concern by solar photo electro-Fenton process in a solar electrochemical raceway pond reactor

This work proposes the degradation of different contaminants of emerging concern (CECs) present in a secondary effluent from a municipal wastewater treatment plant in a solar electrochemical raceway pond reactor (SEC-RPR), applying the solar photo electro-Fenton (SPFE) process. Tap water and a secondary effluent were enriched with 100 µg L−1 of 7 CECs to study the degradation of these compounds by the SPEF process in a SEC-RPR. Among the results obtained, an elimination over 96% and 90% of 5 CECs (progesterone, estradiol, ibuprofen, diclofenac and estrone) was achieved, while sulfamethazine and carbamazepine were eliminated by 73, 37% and 80, 66% after 1 h of treatment, respectively. In turn, a secondary effluent that already achieved the minimum organic load standards established by Chilean regulations was treated in a SEC-RPR by applying different electrochemical advanced oxidation processes (EAOPs). However, regardless of the applied treatment (SPEF, electro-Fenton and electro-oxidation/H2O2), it was possible to further reduce the organic content and even mineralize it. These experiments were performed at pH 3, with Na2SO4 0.05 mM, Fe2+ 0.05 mM and applying a current density of 20 mA cm−2. The SPEF process implemented in a SEC-RPR is presented as an excellent alternative for the treatment of municipal wastewater, due to the large contact area between the effluent and UV radiation, in addition to the continuous and homogeneous generation of H2O2, which allows for the production of hydroxyl radicals in solution, favoring the degradation and mineralization of pollutants.

Neutral (Fe3+-NTA) and acidic (Fe2+) pH solar photo-Fenton Vs chlorination: Effective urban wastewater disinfection does not mean control of antibiotic resistance

Solar photo-Fenton (SPF) process in raceway pond reactors was investigated at neutral pH by Fe3+-NTA complex and at acidic pH by Fe2+and compared with chlorination process in E. coli inactivation, antibiotic Trimethoprim (TMP) and antibiotic resistance genes (ARGs) removal from secondary treated urban wastewater. E. coli inactivation below the detection limit (DL) was achieved in less than 15 min under acidic pH. At neutral pH, the DL was reached in 60 min treatment with 0.2 mM of Fe3+-NTA and 4.41 mM of H2O2. In contrast, the removal of TMP (50 µg/L) by SPF was higher at neutral pH (95%) compared to the acidic pH condition (80%). Although chlorination (10 mg/L chlorine dose) inactivated E. coli below the DL between 2.5 and 5 min, no degradation of TMP was observed. Target ARGs (quinolone, sulphonamides, β-lactams, cephalosporins and tetracycline classes), class 1 integron integrase (intI1) and the 16 S rRNA gene, were only slightly removed under realistic conditions (32% and 23% as max removals of intl1 by chlorination and SPF at acidic pH, respectively) and may not effectively control the potential of antibiotic resistant spread under the mild oxidation conditions investigated in this study.

Large-scale raceway pond reactor for CEC removal from municipal WWTP effluents by solar photo-Fenton

Continuous flow solar photo-Fenton process has been carried out at demonstration scale at flow rates up to 18 m3 h−1 as an advanced treatment for the removal of contaminants of emerging concern, CECs. A 100-m2 raceway pond reactor, RPR, has been built in the WWTP of Almeria city, Spain. The fluid dynamics study showed plug-flow in the reactor channels and perfect mixing in the bends and paddlewheel sections, giving rise to long mixing times. Consequently, for CEC removal the RPR was operated in continuous flow mode at 1 h of hydraulic residence time and acidic pH, with 0.1 mM FeSO4 and 1.47 mM H2O2. Liquid depth was set at 10 cm in winter and 18 cm in summer, achieving > 85% of CEC removal in both cases. For the first time, CEC removal by solar photo-Fenton has been demonstrated under real operational conditions paving the way for its commercial application.

Mechanistic modeling of solar photo-Fenton with Fe3+-NTA for microcontaminant removal

This work presents, for the first time, a mechanistic model of the solar photo-Fenton process with ferric nitrilotriacetate (Fe3+-NTA), the most cost-effective iron source for microcontaminant removal at neutral pH. The model was developed in three stages, considering the thermal decomposition of Fe3+-NTA, the contribution of temperature on Fenton-like reactions and the effect of the photon absorption of Fe3+-NTA on photochemical reactions. To determine the kinetic parameters, the imidacloprid degradation data (100 µg L−1) obtained at lab scale with 1.47 mM of H2O2 and 0.1 mM of Fe3+-NTA at different temperatures, UVA irradiances and liquid depths were used. The model was successfully validated in raceway pond reactors, changing the scale from 0.84 L to 80 L. According to model predictions, more than 90% of microcontaminant removal could be attained in 30 min operating the photoreactor with liquid depths of 15 cm and 60 cm in winter and summer, respectively.