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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Read across substance C12-C16 ADBAC biodegraded almost completely in conventional biological waste water treatment plant based a study that showed more than 99.998% removal was observed for C12-16 ADBAC in a waste water treatment simulation test and and 0.016 to 0.023 % via adsorption to sludge. The same can be expected of C12-C18 TMAC since both substance have structural similarities,  similar physical-chemical properties and similar environmental fate properties.  

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A guideline study was performed to determine the biodegradation of the read-across substance C12-C16 ADBAC in a continuous activated sludge test (CAS). The micoorganisms were maintained by addition of domestic wastewater, were exposed to a nominal concentration of 49 mg/L (36 mg/L carbon) of the test substance for an exposure period of 58 days. A control fed with domestic wastewater only was was included in the test. Using

non purgeable organic carbon (NPOC) contents in the control and test units, a strong increase of NPOC concentration was noted on Day 2. The high NPOC concentration was likely caused by toxic effects of the test substance. The activated sludge acclimatised to the test substance within a few days resulting in a decrease of the NPOC concentrations. After 3 weeks very high carbon removal percentages were achieved. The mean removal percentage of test substance -carbon calculated over 15 measurements obtained during the last three weeks (Day 48 to Day 58) of the test was 99.8%. This indicates that the test substance is ultimately biodegraded. Specific analyses were performed to assess the removal of the parent compound. The mean removal percentage in the test unit assessed with a HLPC-MS/MS method was 99.998%. This analysis demonstrated that the primary biodegradation of the test substance was almost complete or complete. Removal of the test substance from the influent through adsorption onto sludge was only 0.016 to 0.023% at Day 57 and Day 58 respectively, demonstrating that the test substance was removed almost completely biodegraded(van Ginkel CG and Geerts R, 2007).