S. T. SCHULTZ and E. D. PEDERSON
[Naval Dental Research Institute, Building 1-H, 2701 Sheridan Road, Great Lakes, Illinois, 60088-5259, USA]
In continuing environmental research, the Naval Dental Research Institute (NDRI) has characterized the physical and chemical properties of dental wastewater. NDRI has also developed methods to remove heavy metal pollutants including mercury from the operatory-waste stream. The aim of this study was to evaluate a method to remove polymer-bound mercury (NALCO) by means of a filter press (NETZSCH). A total of 539 liters of dental wastewater was treated with 3.33 ml/liter of the polymers. Mercury levels were measured in the mixed wastewater before polymer addition and in polymer-treated samples collected during filtration through the filter press. The initial concentration of mercury in the wastewater was 100 mg/liter. Samples were collected at time zero and at 10 minute intervals during the filtration process. Mercury levels in the samples decreased more than 25-fold after 60 minutes of filtration, indicating greater filtering efficiency as the sediments built up in the filter press. This process consistently removed greater than 99% of the total mercury in these wastewater samples. The treatment method is capable of removing the vast majority of mercury contaminants from dental wastewater. Supported by NMRDC, Project Number 0603706N M0095.006-0515. [Journal of Dental Research 77:243 #1103, 1998]
NDRI Dental Mercury Environmental Issues