Application of Response Surface Methodology to Electrocoagulation Treatment of Hospital Wastewater

Abstract

This study investigates the treatments of hospital wastewater by electrocoagulation using Fe, Al, and stainless steel (SS) electrodes in a batch electrochemical reactor. Parameters that affected the removal of total organic carbon (TOC) of the wastewater with a pH from 5 to 8 and a current density (CD) ranging from 2.03-4.87 mA/cm 2 were examined. The optimum conditions were determined using response surface methodology. In accordance with the suggested mathematical models, maximum TOC removal efficiency was calculated as 99.11% (pH 7.56, CD 4.87 mA/cm 2 ), 99.91% (pH 5.45, CD 4.46 mA/cm 2 ), and 99.89% (pH 7.80, CD 2.68 mA/cm 2 ) for the Fe, Al, and SS electrodes, respectively. The experimental results were also in reasonable agreement with the used model. For all electrodes, the removal efficiencies were high. After analysis of variance (ANOVA), the determination coefficients of the models were R 2 Al 99.87%, R 2 Fe 96.02%, and R 2 SS 94.15% showing that the quadratic models were a good fit and of high significance. The model predictions were confirmed to be appropriate to the experimental data with a deviation of <2.5%. In addition, the SS electrode is better than the Fe and Al electrodes according to energy consumption cost.

Techno‐economical optimization using Box–Behnken (BB) design for chemical oxygen demand and chloride reduction from hospital wastewater by electro‐coagulation

“…The F ‐test has been used to understand the significance of the model. The prerequisite for decent significance of model term is that the F ‐value must be higher and p ‐value must be lower (Veli et al., 2016). The higher model F ‐value of 107.60 and 436.37 for COD and chloride removal respectively showed strong significance.…”

“…HWWs contain a variety of hazardous substances such as heavy metals, pharmaceutical active compounds (PhACs), disinfectants and solvents and various other detergents generated from laboratories, research activities, and clinics (Dehghani, Seresht, & Hashemi, 2014; Yusuf, Lubis, & Adisalamun, 2019). Such toxic effluents and micro‐pollutants without prior treatment are usually discharged to sewage network of urban wastewater from where it is carried to the local municipal wastewater treatment plant (Veli, Arslan, & Bingöl, 2016; Verlicchi, Galletti, Petrovic, & Barceló, 2010). Recently, effluents from hospitals have been given more attention toward treatment as these wastewaters can cause adverse effects on humans as well as on flora and fauna.…”

“…Recently, effluents from hospitals have been given more attention toward treatment as these wastewaters can cause adverse effects on humans as well as on flora and fauna. The HWWs are toxic in nature and requires pre‐treatment or on‐site treatment before disposal to local sewage network so that the urban wastewater collection system and environment does not get much contaminated (Veli et al., 2016).…”

“…In this method, current passes through the electrodes (mostly iron (Fe) and aluminum (Al)) and generates coagulating agent and gas bubbles when the current is applied across electrodes which can remove color, suspended, and dissolved particles in wastewater (Sahu, Mazumdar, & Chaudhari, 2014). Following equations, that is, 1, 2, 3, and 4 takes place at anode and cathode and in the solution during the process (Veli et al., 2016):…”

Optimisation of biological wastewater treatment for yeast processing effluent using cultured bacteria: Application of response surface methodology

“…Using the Design Expert Software 7, the responses from the data were analysed. To evaluate the goodness-of-fit of the mathematical models, analysis of variance (ANOVA) was used in a confidence interval of 95% (Veli et al, 2016). The ANOVA results for all responses were summarized.…”