Design and evaluation of a filter-based chairside amalgam separation system

Area of Science:

• Environmental Science
• Occupational Health
• Materials Science

Background:

• Dental procedures, particularly those involving amalgam, release mercury (Hg) into wastewater.
• Effective removal of mercury from dental wastewater is crucial for environmental protection and regulatory compliance.

Purpose of the Study:

• To evaluate the efficacy of a chairside filtration system in removing particulate mercury from dental-unit wastewater.
• To compare the performance of different filter pore sizes (50, 15, 1, and 0.5 micrometers) in mercury removal.

Main Methods:

• A chairside filtration system with disposable filter elements was tested in five dental operatories.
• Wastewater samples were collected daily for ten days and analyzed for mercury concentration using cold vapor atomic absorption spectrometry.
• Filter configurations were systematically rotated, and amalgam placement/removal surfaces were recorded as covariates.

Main Results:

• The chairside filtration system significantly reduced mercury levels in dental wastewater.
• Removal efficiencies ranged from 92.7% (50 microm) to 99.6% (0.5 microm).
• The 0.5 micrometer filter exhibited the highest mercury removal efficiency and passed the ISO 11143 protocol at 96.8%.

Conclusions:

• Chairside filtration systems are highly effective in removing particulate mercury from dental wastewater.
• The 0.5 micrometer filter element is the most efficient option for mercury removal in this system.
• This technology offers a practical solution for reducing mercury discharge from dental practices.