Title: Using Central Composite Face Design (CCFD) and Response Surface Methodology (RSM) systems to develop and optimize a sewage wastewater treatment program

Abstract

The increasing demand for fresh water due to the ever-increasing world population has compelled scientist to find ways to recycle wastewater to increase the supply of fresh water. The presence of organic matters and solids which have adverse effects on the wastewater have necessitated that a simpler and more efficient purification method is developed for faster response to the demand. The coagulation-flocculation process is one of the most efficient and simple chemical treatment processes for wastewater. Its mechanism involves the aggregation of suspended solid particles into settleable flocs by charge neutralization of colloids which had kept the particles apart. Iron and aluminium salts are mostly used to neutralize the colloids to form larger flocs which can be separated from the liquid phase by sedimentation or filtration. In developing and optimizing a wastewater treatment program for the treatment of sewage wastewater, Central Composite Face Design (CCFD) and Response Surface Methodology (RSM) were utilized to develop the experimental design, establish the relationship between the independent variables - the coagulant and flocculant dosages, and the responses - the turbidity and the total dissolved solids removal. The optimal dosages for the coagulant (120.9 ppm of U6750) and the flocculant (125 ppm of Floc887) yielded optimal removal efficiencies of 93.3% and 23.2% for turbidity and TDS, respectively. This shows that the developed treatment using the coagulant, U6750, and the flocculant, Floc887, improved the physical characteristics of the wastewater.