Response Surface Analysis and Statistical Modeling of Sulfide Generation from Municipal Wastewater

Abstract

In this study, the interactive effects of four independent variables (initial chemical oxygen demand (COD) concentration, rotational velocity, temperature, and retention time) on the sulfide generation process in municipal wastewater were investigated. The process was modeled and analyzed with the variables in a series batch experiments. Experiments were conducted based on a central composite face-centered design and analyzed using response surface methodology. The region of exploration for the process was taken as the area enclosed by COD (250 and 650 mg/L), rotational velocity (40 and 200 rpm), temperature (16 and 288C), and retention time (2 and 40 h) boundaries. Eleven dependent parameters were either directly measured or calculated as response. The most influential variable on H 2 S (g) production was found to be retention time. The results showed that simultaneous increase in temperature and rotational velocity caused an increasing trend in the amount of H 2 S (g) emitted. Total sulfide was decreased by increasing rotational velocity due to more H 2 S (g) secretion resulting from increased mixing rate. The present study provides valuable information about interrelations of quality and process parameters at different values of the studied variables.

Optimization of Lead and Nickel Biosorption by Cystoseira trinodis (Brown Algae) Using Response Surface Methodology

“…This shows that >97% of the experimental data is compatible with the data predicted by the model (Table 3) and only <5% of the total variation is not explained by the proposed equation. Simultaneously, low values of the coefficient of variation (CV; 0.88-5.29) indicate good precision and [37] and Amini and Younesi [24]. The predicted versus actual plot for the two responses is shown in Fig.…”