Effectiveness and Optimization of Chlorine Tablets for Total Coliform Removal in Hospital Wastewater Effluent

Abstract

Background: Hospital wastewater contains diverse pathogens and chemical contaminants that pose serious risks to public health and the environment. In Indonesia, conventional treatment systems often fail to meet microbial quality standards, leading to potential secondary pollution. Chlorination is widely used as a disinfection method; however, its practical application using chlorine tablets in hospital wastewater management remains limited. Objective: This study introduces an innovative, low-cost, and context-specific optimization of chlorine tablet dosage and contact time for hospital wastewater disinfection under tropical Indonesian conditions. Methods: A preliminary survey at a hospital in Surakarta showed total coliform levels of 5,400 MPN/100 mL, exceeding the national limit of 3,000 MPN/100 mL (Regulation No. 68/2016). A pretest–posttest batch experiment was conducted using chlorine tablet dosages of 200 g, 400 g, and 600 g, with contact times of 30, 40, and 50 minutes. Parameters measured included total coliform, pH, and temperature to evaluate disinfection efficiency and stability. Results: Total coliform removal efficiencies were 68% (200 g/50 min), 99.87% (400 g/40 min), and 100% (600 g at all durations). Although higher doses enhanced microbial removal, the 600 g treatment inc9reased pH above 8.0, reducing chlorine stability and increasing residual chemical risk. Conclusion: The optimal condition was 400 g of chlorine with a 40-minute contact time, achieving 99.87% total coliform removal while maintaining safe pH levels. This study presents a novel, efficient, and cost-effective chlorination optimization model for hospital wastewater disinfection, supporting sustainable and regulation-compliant wastewater management in developing countries.