Abstract
The increasing demand for pharmaceutical products has led to a rise in pharmaceutical wastewater, which poses serious environmental and health threats due to the presence of complex contaminants including high chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solids (TSS), heavy metals, and residual pharmaceutical compounds. Traditional treatment systems struggle to meet regulatory standards, especially in countries like Malaysia where stringent discharge limits are enforced under the Environmental Quality Act 1974 - Environmental Quality (Industrial Effluent) Regulations 2009. In the present study, a proposed methodology applies a stagewise treatment structure, from preliminary to advanced treatment, integrating various physical, chemical, and biological technologies for the effective reduction of key water quality parameters. A graph-theoretic method known as P-graph structure generation algorithms was further implemented to study multiple feasible treatment pathways. Each configuration was assessed based on pollutant removal efficiency of COD, BOD, TSS and economic viability. A case study was solved to simulate the application of this framework, demonstrating its capability to identify optimal treatment networks that comply with the Environment Quality Regulations 2009 while minimizing operational costs. This research highlights the potential of P-graph modelling as a practical decision-support tool for pharmaceutical wastewater. It helps design pharmaceutical wastewater treatment systems that are both affordable and meet environmental regulations.
