Sewage Treatment – Radioactive Wastewater Treatment Technology

Discover advanced radioactive wastewater treatment technologies used in hospital sewage treatment systems. Learn about the sources of radioactive wastewater, design principles of decay tanks, discharge standards, and radiation safety monitoring for compliant and eco-friendly management.

With the rapid development of nuclear medicine and radiation-based diagnostics, hospitals are increasingly using radioisotopes for disease diagnosis, imaging, and targeted radiotherapy.
While these technologies bring tremendous benefits, they also generate radioactive wastewater, which contains unstable isotopes that emit ionizing radiation and pose environmental and health risks.

Therefore, the safe collection, decay, treatment, and discharge of such wastewater is a key requirement for all medical institutions handling radionuclides.

Radioactive wastewater in hospitals mainly originates from the following:

• Patient Excreta:
  Waste from patients who have received radioactive isotopes (through oral intake, injection, or inhalation) for diagnostic or therapeutic purposes.
• Laboratory Cleaning Water:
  Wash water from laboratories handling isotopes, radioactive containers, glassware, syringes, or labeled compounds.
• Equipment Rinse and Packaging Residue:
  Water used to clean isotope packaging materials, storage vessels, or transport containers.

Depending on isotope usage, the concentration of radioactivity in wastewater can range from 3.7 × 10² Bq/L to 3.7 × 10⁵ Bq/L, while water generation volume typically ranges from 100–200 L per bed per day.

Radioactive wastewater discharge must comply with the “Pollutant Discharge Standards for Medical Institutions”.
The regulation defines the allowable limits for radioactive content at the treatment facility outlet as follows:

• Total Alpha Activity: < 1 Bq/L
• Total Beta Activity: < 10 Bq/L

These limits ensure that the treated effluent poses no environmental hazard or risk to public health. All discharges must be monitored regularly and documented according to radiation safety regulations.

To prevent cross-contamination and facilitate targeted treatment, radioactive wastewater must be collected separately from general hospital sewage.

Design principles include:

• Separate pipelines for radioactive domestic sewage and radioactive test/laboratory wastewater.
• Use of corrosion-resistant pipes, such as stainless steel or high-density polyethylene (HDPE).
• Avoidance of shared drainage lines to ensure radiation safety and system integrity.

Process Flow Example:

1. Radioactive wastewater from laboratories and patient wards →
2. Collection pipelines →
3. Decay Tank System →
4. Monitoring and radiation testing →
5. Safe discharge into municipal sewage or treatment plant (after decay).

The decay tank (or decay pond) is the core component of the radioactive wastewater treatment system.
It allows natural radioactive decay to occur over time, reducing radioactivity to safe levels before discharge.

Design Considerations:

• Type of isotope:
  The decay tank size and configuration are based on the isotope’s half-life and radioactivity level.
• Hydraulic retention time:
  Typically calculated for 10 half-lives of the longest-living isotope in use.
• Structure:
  • Intermittent Decay Tanks: Used for batch-type discharge; multiple compartments allow alternate filling and emptying.
  • Continuous Decay Tanks: Designed with diversion walls and a plug-flow pattern to ensure consistent decay and flow.
• Construction materials:
  Tanks must be anti-seepage, anti-corrosive, and radiation-shielded to prevent leakage and contamination.

Effective operation of radioactive wastewater treatment facilities depends on regular monitoring, record-keeping, and safety checks.

Monitoring Requirements:

• Intermittent decay tanks:
  Radiation levels must be measured before each discharge to confirm compliance with alpha and beta limits.
• Continuous decay tanks:
  Radiation monitoring should be conducted at least once per month.
• Septic tanks or radioactive treatment ponds:
  Must be cleaned every six months after confirming radiation levels are below safety thresholds.

Management Practices:

• Keep detailed logs of isotope usage, wastewater volume, decay time, and discharge activity levels.
• Ensure staff involved in radioactive wastewater handling receive radiation protection training.
• Implement emergency containment measures in case of accidental leaks or equipment failure.

Beyond passive decay, some modern systems integrate secondary treatment technologies to enhance safety and environmental performance:

• Ion exchange and adsorption units – to remove remaining radionuclides.
• Evaporation or concentration systems – for reducing waste volume.
• Shielded monitoring rooms – for real-time radiation monitoring.
• Automation and remote control systems – to minimize human exposure.

These advancements align with international standards such as the IAEA (International Atomic Energy Agency) guidelines for radioactive waste management.

The management of radioactive wastewater in hospitals is a highly specialized process that requires precision, safety, and regulatory compliance.

By adopting separate collection systems, scientifically designed decay tanks, and regular radiation monitoring, hospitals can ensure that effluent discharge meets environmental protection standards.

As nuclear medicine continues to expand, integrating smart monitoring, automated decay systems, and advanced treatment technologies will be crucial for sustainable and safe hospital wastewater management.

Radioactive wastewater is liquid waste containing radioactive isotopes, primarily generated during medical diagnosis or treatment involving radioisotopes.

Separate collection prevents contamination of non-radioactive sewage and ensures accurate decay and treatment tailored to isotopic properties.

Typically for 10 half-lives of the longest-lived isotope to ensure the radioactivity decays to safe levels before discharge.

Common materials include stainless steel and HDPE (High-Density Polyethylene), which are corrosion-resistant and radiation-safe.

Facilities must perform alpha and beta activity testing before discharge, following national discharge standards (<1 Bq/L α, <10 Bq/L β).

Xi’an CHIWATEC Water Treatment Technology is a high-tech enterprise specialized in various water processing devices. Aside from these individual products, which cover a number of types and series, we can also help with related comprehensive engineering projects. Thanks to our hard work and dedication upon our founding, we are now one of the fastest-developing water treatment equipment manufacturers in Western China.

Further reading:

• Hospital
• Application of hospital pure water central processing system
• Hospital sewage treatment process
• Hospital Wastewater Treatment System
• Hospital sewage disinfection technology
• Sludge and waste gas treatment technology of hospital sewage treatment system
• Requirements for construction of hospital sewage treatment equipment
• How to deal with the sewage in the ophthalmology hospital?
• Hospital wastewater source
• Analysis of Application Advantages of Hospital Pure Water Central Processing System