1.Introduction
When individuals fall ill, some opt for over-the-counter medications from pharmacies, while others seek hospital care—particularly for severe conditions that cannot be managed with self-administered treatments. Hospitals, as complex multi-departmental institutions, generate medical wastewater, defined as the effluent discharged by hospitals into natural environments or municipal sewer systems. Beyond domestic sewage components, medical wastewater contains hazardous substances such as chemicals and pathogens.
A core principle governing medical wastewater management is that it must undergo treatment prior to discharge, with strict prohibitions on the direct release of wastewater contaminated by infectious diseases (e.g., hepatitis). To ensure compliance with discharge standards, wastewater must first be disinfected and sterilized, followed by rigorous monitoring to verify that all (indicators) meet regulatory requirements.
2.Key Monitoring Indicators for Medical Wastewater
2.1 Conventional Water Quality Indicators
These indicators are universally monitored across water-related industries and form the foundation of wastewater assessment:
a.pH Value
The pH value quantifies the ratio of hydrogen ion concentration to total substance concentration in a solution. Extreme pH levels (high alkalinity or low acidity) disrupt water stability and degrade water quality.
b.Suspended Solids (SS)
SS refers to solid particles suspended in water, including organic matter, inorganic debris, and microorganisms. It is a critical indicator for evaluating water pollution severity.
c.Chemical Oxygen Demand (COD)
COD is a quantitative method to measure the concentration of reducible substances in water that require oxidation, reflecting the organic pollution load of the wastewater.
d.Ammonia Nitrogen
Ammonia nitrogen primarily exists in water as free ammonia (NH₃) and ammonium ions (NH₄⁺). Nitrogen-containing organic matter in human and animal feces is unstable and readily decomposes into ammonia, making this indicator relevant to organic contamination from biological waste.
e.Total Phosphorus (TP)
TP measures all forms of phosphorus converted to organophosphate via digestion, expressed in milligrams of phosphorus per liter of water sample (mg/L). It is a key indicator for assessing nutrient pollution.
2.2 Specialized Indicators for Medical Wastewater
Two indicators are uniquely critical for medical wastewater due to its pathogen and disinfection-related risks:
a.Cruciform Bacteria
Cruciform bacteria inhabit the intestines of humans and warm-blooded animals and are excreted in feces, accounting for approximately one-third of fecal dry weight (termed fecal lifeforms). Real-time monitoring of this indicator can be performed using the Hangzhou Modi WECT-900 Online Cruciform Analyzer.
b.Total Residual Chlorine
Residual chlorine is the remaining effective chlorine in water after chlorination disinfection. Excessive residual chlorine may cause organ irritation in humans and, in severe cases, paralyze the respiratory center. Thus, chlorine dosage must be strictly controlled within limits specified by Chinese regulatory standards. The RCl900 Online Total Residual Chlorine Analyzer is commonly used for continuous monitoring.
3.Conclusion
The monitoring of medical wastewater involves both conventional water quality indicators (pH, SS, COD, ammonia nitrogen, TP) and specialized indicators (cruciform bacteria, total residual chlorine). Rigorous monitoring ensures that treated medical wastewater meets discharge standards, mitigating environmental and public health risks.
Note: Technical terms (e.g., COD, SS, residual chlorine) are retained in their standard abbreviated forms for academic consistency. Brand names of monitoring equipment are preserved as specified.
