The Application of Response Surface Methodology in the Study of Photodegraded Industrial Dairy Effluents by the Photo-Fenton Process: Optimization and Economic Viability

Abstract

This study presents results from an application of Photo-Fenton process for organic-load reduction in dairy effluents. Process efficiency was evaluated in terms of percentage dissolved organic carbon, chemical oxygen demand, and biochemical oxygen demand (DOC, COD, and BOD, resp.), whose initial values were 1658 ± 145 mg O 2 L −1 , 9500 ± 500 mg O 2 L −1 , and 2400 ± 100 mg O 2 L −1 , respectively. We applied a statistical design represented by Box-Behnken factorial design inclusive of Fenton's reagent, the power of applied radiation (W), and pH factors. The set temperature value was 30 ∘ C with a reaction time of 60 min. The maximum efficiency obtained was at pH = 3.5, Fenton reagent in the proportion of 35 g H 2 O 2 + 3.6 g Fe 2+ , and ultraviolet radiation potency of 28 W. The results obtained for DOC, COD, and BOD were 81%, 90.7%, and 78.8%, respectively. Regarding the cost/benefit evaluation, the variables and their levels should be the following: pH 3.5, 35.0 g H 2 O 2 /Fe 2+ 3.6 g, and 28 W UV, obtaining a reduction in concentration of 79.5% DOC.

Tratamento híbrido de soro de queijo bruto pela combinação dos processos de biocoagulação, oxidação avançada e reator anaeróbio

“…Apresentou propriedades ácidas, com a faixa de pH entre 3,5 e 4,5, e salinas, com condutividade elétrica de 2,052 μS cm -1 , características comumente encontradas em efluentes de SQ. Além disso, verificou-se que o grau de matéria orgânica recalcitrante presente no SQ na razão DBO 5 /DQO, de 0,38, dificultaria o tratamento biológico convencional de forma direta (LOURES et al, 2014)…”

Optimization of Anaerobic Treatment of Cassava Processing Wastewater

“…As the COD/BOD ratio is 4.2, the wastewater can be considered biodegradable only if the factors influencing the process are suitable for microbial metabolism. If the ratio is 5.0 > COD/BOD > 2.5, a proper biological process should be chosen in order to reach a desirable reduction of organic matter (LOURES et al, 2014).…”

Comparative Study of Data Analysis Techniques for Photo-Fenton Degradation of Landfill Leachate

“…Analysis of this dual behavior is important, given that changes in reaction conditions, such as reagent feed flow rates, may influence the process, possibly precluding radical oxidant consumption or resulting in low oxidation of carbonaceous compounds. 30 This study is aimed to compare the empirical model proposed by Siqueira and collaborators with two approaches for the investigation of leachate degradation. 28,29 The first approach is a kinetic model developed by Izaŕio Filho et al 26 and applied by Izaŕio Filho et al 27 It is based on the main kinetic equations found in the literature for AOPs and was successfully applied in the study of photo-Fenton degradation of undiluted industrial wastewater.…”

“…In studies on leachate treatment by AOPs, it was found that stochastic modeling allowed using all experimental data, contributing to a broader understanding of the degradation process and favoring optimization. − Two distinct phases of the oxidation process were identified, a first phase occurring very rapidly and a second phase occurring at a slower rate. Analysis of this dual behavior is important, given that changes in reaction conditions, such as reagent feed flow rates, may influence the process, possibly precluding radical oxidant consumption or resulting in low oxidation of carbonaceous compounds …”