Background: Hospital wastewater is an important component of urban wastewater and exhibits distinct quality characteristics due to the variety of healthcare services provided. These properties have necessitated the installation of on-site treatment systems in most hospitals. This study aimed to evaluate the performance of such systems in Tehran hospitals with respect to Iranian national standards and to identify factors influencing their efficiency. Methods: Data on the quantity and quality of hospital wastewater were collected from six hospitals in western Tehran in 2024. Parameters including pH, dissolved oxygen (DO), temperature, chemical oxygen demand (COD), biochemical oxygen demand (BOD), total suspended solids (TSS), nitrate, phosphate, and chloride were analyzed in both raw wastewater and treated effluent according to Standard Methods for the Examination of Water and Wastewater. Statistical analyses, including t-tests performed in Microsoft Excel, were used to interpret the results. Results: The average wastewater generation rate among the studied hospitals was 511 liters per bed per day. The highest and lowest pollutant removal efficiencies were recorded for TSS (94.6%) and chloride (26.1%), respectively. Half of the treatment plants achieved effluent quality compliant with national standards for BOD and COD, whereas nitrate concentrations exceeded permissible limits in 75% of facilities discharging effluent into wells. Conclusion: Although most effluent parameters met national standards, enhancing treatment capacity and optimizing operational conditions, through the installation of advanced treatment units and the employment of skilled operators, are essential steps toward improving hospital wastewater quality.
Tashauoei et al. (Sun,) studied this question.