Reducing chemical oxygen demand from low strength wastewater: A novel application of fuzzy logic based simulation in MATLAB

Wastewater reuse is a significant challenge around the world, especially in arid and semi-arid regions. In order to analyse wastewater reuse applications, chemical oxygen demand (COD) is an essential factor for tertiary treatment processes. The purpose of this study is to design an approach to evaluate COD removal from low-strength wastewater (COD 70 mg/L) for reuse. This algorithm involves two steps: 1) Activated carbon-activated sludge (AC-AS) and activated sludge-algae (AS-Algae) were investigated, and 2) Optimal conditions were determined through statistical analysis of data. Despite its inherent advantages and robustness, fuzzy logic is a well-recognised alternative algorithm in control applications. As a result of the AC-AS process, an 85% COD removal rate was achieved in 8 hours by combining 0.05 g/L AC and 5 mL/L AS. Under optimal experimental conditions (5 mL/L of AS and 7 mL/L of Algae), a 60% COD removal rate in 7 h was achieved for the AS-Algal process. Both the AC-AS and the AS-Algal systems were found to have 85% and 59% removal efficiencies, respectively. Experimental and predicted values of the AC-AS system and the AS-algal system showed excellent correlation, with a determination coefficient of 0.99 (AC-AS system) and 0.93 (AS-algal system).