To achieve the safe discharge of medical wastewater, it is imperative to first identify the hazardous substances contained in hospital effluent and clarify the parameter standards during treatment, thereby enabling targeted pollution control. This article provides a concise overview of the discharge indicators and standards for hospital wastewater.
Explanation of Medical Wastewater Discharge Indicators
Routine monitoring of conventional pollutants is mandatory for all wastewater types, including parameters such as pH, total phosphorus (TP), total nitrogen (TN), ammonia nitrogen (NH₃-N), chemical oxygen demand (COD), and suspended solids (SS). For medical institutions, however, regulatory authorities require real-time online monitoring of two key indicators—coliform bacteria and total residual chlorine—to ensure the safety of discharged wastewater, in addition to the aforementioned conventional parameters.
1.Coliform Bacteria
Coliform bacteria are a group of intestinal bacteria naturally occurring in the digestive tracts of warm-blooded animals and humans, which are excreted via feces. The WECT-900 Online Coliform Analyzer is typically used to monitor their concentration, as this indicator serves as a proxy for assessing the overall level of pathogenic bacterial contamination in wastewater.
2.Total Residual Chlorine
Chlorination is a widely adopted disinfection method for medical wastewater. However, strict control of residual chlorine levels is critical: excessive residual chlorine in water can cause irritation to the eyes and nasal mucosa, and in severe cases, lead to pulmonary edema or respiratory center paralysis due to neurotoxic effects. Therefore, staff must not only avoid direct contact with disinfectant solutions but also implement continuous online monitoring of total residual chlorine. Notably, this requirement does not apply if alternative disinfectants are used.
Discharge Standards for Medical Institution Wastewater
The national standard governing medical wastewater discharge in China is GB 18466-2005 Discharge Standard of Water Pollutants for Medical Institutions. This standard specifies control items, emission limits, and control requirements for pollutants in wastewater, exhaust gases, and sludge generated from medical wastewater treatment. It also outlines technical specifications for disinfection processes, sampling protocols, and monitoring methods, serving as a regulatory framework to ensure compliance and environmental safety.
