Medical wastewater discharged from hospitals and healthcare institutions is known to contain high loads of pathogens, viruses, and other hazardous substances. Classification of such wastewater may be based on hospital type—primarily into infectious disease hospital wastewater and general hospital wastewater—or by water quality composition, including pharmaceutical waste wastewater, heavy metal-containing wastewater, and radioactive medical wastewater. The comprehensive treatment of medical wastewater encompasses both disinfection and monitoring processes. This paper aims to provide an overview of the Monitoring for Medical Wastewater programs disinfection efficacy.
1.Overview of Disinfection Processes
Multiple disinfection methods are employed for medical wastewater, including chlorination, ultraviolet (UV) disinfection, and ozonation. Chlorination is the most widely used approach, which can be further categorized into liquid chlorine disinfection, sodium hypochlorite dosing, and chlorine dioxide disinfection. The core objective of disinfection is to eliminate pathogens in wastewater and ensure compliance with discharge standards for water quality indicators.
Hospital wastewater exhibits complex characteristics, with pollutant concentrations typically increasing with water volume. The equalization tank plays a critical role in the treatment process: it not only regulates water volume but also stabilizes water quality, thereby preventing fluctuations in influent conditions from compromising treatment efficiency. In summary, medical wastewater must meet regulatory disinfection standards prior to discharge.
2.Assessment of Disinfection Efficacy via Monitoring
Disinfection efficacy is evaluated through wastewater monitoring, which verifies whether all indicators meet specified standards and harmful substances are reduced to safe levels. Key monitoring parameters are divided into two categories:
2.1 Parameters for Health Supervision Inspections
– Salmonella: monitored quarterly
– Shigella: monitored semi-annually
– Fecal coliforms: monitored monthly
2.2 Parameters Aligned with Discharge Standards by Environmental Protection and Water Authorities
– Routine indicators: ammonia nitrogen, chemical oxygen demand (COD), total phosphorus, etc.
– Special parameters: animal and vegetable oils, etc.
– Coliform bacteria (for assessing bacterial load; measurable via the WECT-900 Online Coliform Analyzer)
– Total residual chlorine (monitored only when chlorine-based disinfectants are used; measurable via the RCl900 Online Total Residual Chlorine Analyzer)
– Anionic surfactants
