Volume 8, Issue 10 (November 2011)
A New Way to Determine the Biodegradability of Lubricants by a Biokinetic Model
With advanced lubrication technology, natural resources have been turned into lubricants which are no longer recognizable by microorganisms and enzymes that convert natural substances into their basic building blocks. To make more environmentally friendly products, significant efforts are on-going to develop biodegradable materials and technologies which are fully compatible with the environment. One concern in these efforts is the evaluation of their biodegradability in laboratory environments within a short period. Currently, several ASTM and Organization for Economic Co-Operation and Development (OECD) biodegradation test methods are available for determining this environmental property, but these take a long time (28 days) and special biological knowledge is required. Because of these disadvantages, it is very difficult to use in lubrication laboratories for assessing the biodegradability of lubricants. To resolve this problem, a biokinetic model has been developed based on the composition of lubricants. The advantage of this biokinetic model is that it can predict the biodegradability of lubricants within a day without the use of microorganisms. In addition, this new technology resulted in an excellent correlation with the existing laboratory biodegradation tests. Currently, this technology is used in the ASTM D7373 test method. This report presents how to develop a biokinetic model and the results are discussed in a comparison with the Aerobic Closed Respirometer test (ASTM D 6731).