Carbon dioxide biodegradability tests

ISO 9439,1999, Water quality - Evaluation of ultimate aerobic biodegradability of organic compounds in an aqueous medium - Carbon dioxide evolution test International Standard ISO 9439 1999(E), International Oiganization for Standardization (ISO),... 

IS09439 1999 Water quality—evaluation of ultimate aerobic biodegradability of organic compounds in aqueous medium—carbon dioxide evolution test... 

ISO 9439 2000(E), Water Quality - Evaluation of Ultimate Aerobic Biodegradability of Organic Compounds in Aqueous Medium - Carbon Dioxide Evolution Test, International Organization for Standardization, Geneve, Switzerland, 2000. 

Most of the test methods used to assess the anaerobic biodegradability of organic chemicals have been screening level tests based upon measuring the increase in gas volume or pressure resulting from the conversion of a test material to carbon dioxide (C02) and methane (CH4), such as the ECETOC-28 test [3,4],... 

Biological. Complete microbial degradation to carbon dioxide was reported under anaerobic conditions by mixed or pure cultures. Under enzymatic conditions formaldehyde was the only product reported (Vogel et al., 1987). In a static-culture-flask screening test, methylene chloride (5 and 10 mg/L) was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum. After 7 d, 100% biodegradation with rapid adaptation was observed (Tabak et al., 1981). 

The biodegradation of Ecoflex film was tested under composting conditions. After 100 days in a composting environment more than 90% of the carbon in the polymer was converted to carbon dioxide. Tests also showed no toxic effects of degradation intermediates. 

The biodegradation of EnPol polymers was tested in a controlled laboratory composting test and showed that within 45 days a carbon dioxide evolution of more than 90% of the carbon present in the co-polyester was detected. 

Biodegradation testing was done in the biometer described in Figure 3. The environments of choice were mixed with the plastic or degradation products and the rate and degree of carbon dioxide evolution measured by capture in the reservoir of caustic soda solution. 

Figure 3. Biometer for Measuring Carbon Dioxide Evolution in Biodegradation Testing.

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