Aquatic Biodegradability

At CEN level, EN14987 was published in 2006 Plastics - Evaluation of disposability in wastewater treatment plants - Test scheme for final acceptance and specifications. The pass level for biodegradation is 90%, which must be reached within a maximum of 56 days. Aquatic biodegradation tests must be used, with sludge as the only inoculum 

A greater need for additional specifications on water degradability can be expected when more biodegradable flushable products are developed and put onto the market. 

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Ingerslev, F., A. Baun, and N. Nyholm. 1998. Aquatic biodegradation behavior of pentachlorophenol assessed through a battery of shake flask die-away tests. Environ. Toxicol. Chem. 17 1712-1719. 

The experimental determination of COD for most organic compounds agrees well with the theoretically predicted value (TOD) but the BOD is almost always lower. This is to be expected, because complete oxidation does not take place in the aquatic environment. The COD BOD ratio can therefore be regarded as a measure of aquatic biodegradability. The closer this value is to 1 the greater the aquatic biodegradability of the compound. In industrial nutrient discharges it is usually the case that the effluent contains a mixture of nutrients of uncertain composition. It is therefore not possible to... 

Zee, M.E. van der, Stoutjesdijk, J.H., Fell, H. and Feijen, J. (1998b). Relevance of aquatic biodegradation tests for predicting degradation of polymeric materials during biological waste treatment. Chemosphere, 36(3), 461 73. 

Pfaender FK, Bartholomew GW. 1982a. Measurement of aquatic biodegradation rates by determining heterotrophic uptake of radiolabeled pollutants. Appl Environ Microbiol 44 159-164. 

Pfaender, F.K., Bartholomew, G.W. (1982) Measurements of aquatic biodegradation rates by determining heterotropic uptake of radiolabelled pollutants. Appl. Environ. Microbiol. 44, 159-164. 

Polyaspartates, as exemplified by the parent polymer, polyaspartic add, offer an attractive biodegradable alternative to polyacrylates [21]. In addition to thdr activity as scale inhibitors and dispersants, polyaspartates have also been shown to have corrosion inhibition activity, particularly for the corrosion environments frequently found in oil-field applications. Polyaspartates have very high biodegradability as indicated by OECD guidelines for aquatic biodegradability. 

Already there are certain restrictions for certain non-biodegradable plastic packaging materials (the US Plastics Pollution Research and Control Act of 1987, Public Law 100-220 and the Annex of the MARPOL (marine pollution) Convention - the International Convention for the Prevention of Pollution from Ships which prohibit the disposal of plastics at sea, which allowed the US Navy promote the development of aquatic biodegradable plastics at sea. 

Mueller, W.-R. and Joerg, J., 1999, Report of a ring test about aquatic biodegradability for plastics under strict anaerobic conditions based on ISO 11734 and ISO DIS14853, Draft Version, University of Stuttgart, Germany... 

As for aquatic biodegradation, the first standards for soil biodegradation were developed for simple and pure chemical substances, and published as OECD 304 and ISO 11266. For complex samples such as biodegradable polymers, modifications were needed and first introduced by ASTM D5988-96. In 2003, an ISO Norm was also published ISO 17556 - Plastics - Determination of the ultimate aerobic biodegradability in soil by measuring the oxygen demand in a respirometer or the amount of carbon dioxide evolved. 

In the first years of the existence of biodegradable plastics, it became clear that the aerobic, aquatic biodegradation tests were not appropriate to evaluate the biodegradation of these polymers in composting. The environmental conditions are of course very different high temperatures up to 60-65 °C in composting as opposed to ambient temperature in water, different moisture content, etc. An important difference is also the activity... 

ASTM D5864-00, Standard Test Method for Determining Aerobic Aquatic Biodegradation of Lubricants or Their Components, 2000. 

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