Decontamination of drainage pipes is an important element of the project in order to develop more effective and cheaper technologies. The project will work to develop a more effective technology for decontaminating thin, thick and poorly-accessible pipes. New equipment, methods and procedures will be developed to check whether the decontamination method removes all sediments.
Video inspection of pipes
Video inspection equipment will be tested and evaluated as filming is the best tool for getting a clear picture of the inside of the pipes. By carefully examining the films, decontamination methods can be evaluated and improved. Video inspection is carried out both prior to the commencement of decontamination and after completion. For dry systems this means from all dental chairs and downstream. For wet systems, the suction pipe is filmed both from the dental chairs and downstream, as well as from the suction room and upstream.
Video inspection in premises where 142 grams of mercury was collected
Video inspection in premises where 1688 grams of mercury was collected
Testing of mercury-binding chemicals
This sub-project includes testing chemical treatment of pipe systems to reduce mercury leakage from newly-treated surfaces that have been contaminated with metallic mercury. The chemicals bind metallic mercury so that it will not dissolve in water. Mercury content before and after treatment will be evaluated in order to determine the effectiveness of the chemicals. The proposed chemicals have no negative environmental impact. They rapidly degrade into harmless substances so that the original chemicals will not reach the general sewage network.
So far, 18 practices have been decontaminated within the framework of the project and many more are in the pipeline. The collected quantity of elemental mercury varies thus far from 55 to 1,700 grams. So far, a total of 7.9 kilograms of mercury has been collected in the decontaminations carried out (17, results still unavailable for one practice).
Example of pipe before decontamination, autumn 2017.
Water locks that are decontaminated can contain large amounts of amalgam residues, autumn 2017.
What is the procedure for decontamination?
Mercury contaminated drainage pipes, water locks and floor wells are flushed clean. All water from the decontamination process is then collected for post-treatment. Sweden Recycling has mobile flushing devices so that pipes located higher up in a property can be reached. Pipes that have been decontaminated are labelled with the date of decontamination and who performed the work. Decontamination usually takes 3–4 hours.
Treatment of patients can continue immediately after decontamination has been completed.
Disposal of the decontamination waste
The decontamination wastewater and sludge are collected and transported to Sweden Recycling's plant in Växjö for intermediate storage, before further transportation to its sister company Medentex GmbH in Germany for processing.
Sweden Recycling AB and Medentex GmbH have all permits required.