Investigation of pretreatment of procion blue H-EXL dye byadvanced oxidation process and treatmen by mi̇croalgae after pretreatment

Industrial wastewater discharges cause significant environmental problems in worldwide as well as in our country. This also pose major threats to the flora and fauna live in water. Currently, various scientific and industrial studies have been carried out to protect the existing water resources. In this study, advanced oxidation processes such as Fenton, Fenton-like, H2O2/UV, photo- Fenton, and photo-Fenton like were investigated in the pretreatment of color and COD from a synthetically prepared Procion Blue H-EXL dye solution. Following the pretreatment, microalgae were cultivated in the pretreated wastewater to obtain valuable biomass and to implement environmentally friendly advanced treatment methods. The highest color and COD removal efficiency were obtained by Photo-Fenton -like process as 96% and 50%, respectively by using 0.075 g/L Fe(NO3)3, 2,2 mM H2O2 after treated two hours under UVC light. In the Photo-Fenton process, the highest color and COD removal efficiency was obtained using 0,075 g/L FeSO4, 2,2mM H2O2 under the same experimental condition as 95% and 44%, respectively, which is relatively lower than the Photo-Fenton-like process. Microalgal treatment was used in both pretreated solutions separately, with and without adjusting the pH according to the BG11 medium. The specific growth rate of microalgae was determined as 0,33 day-1 in the pretreated wastewater by Photo-Fenton process, whereas no growth was observed in the investigated period when pre-treated with Photo-Fenton-like process. In addition, in our study the specific growth rate of microalgae was cultivated in BG11 medium is obtained 0,24 day-1 which was relatively lower than the one observed in the pretreated water. As a result of the study, it has been shown that the "integrated system" proposed in this study is a viable alternative method for wastewater treatment and production of valuable biomass.