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Environmental fate & pathways

Biodegradation in water and sediment: simulation tests

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Description of key information

Read-across subtance C12-C16 ADBAC will biodegrade almost completely in conventional biological waste water treatment plants.

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Additional information

A guideline study was performed to determine the biodegradation of the structurally similar test substance benzyl C12-16 alkyl dimethyl ammonium chloride in continuous activated sludge test. A solution of 7.2 g/L in deionised water was directly added to the test unit using a syringe pump. The flow rate of the syringe pump was approximately 9.6 mL/d giving a calculated concentration of the test substance in the influent of the unit of approximately 49 mg/L. The domestic sewage supply was supplied at a rate of approximately 1.4 L/d to give a hydraulic retention time of 6 h. A volume of 35 mL of sludge was daily removed from the aeration tank to maintain a sludge retention time of 10 d. Samples were withdrawn from the settler at least 2 times a week for the first 8 weeks. After this period at least 5 samples were taken. All samples were analysed for NPOC. Samples of the last week were analysed for the parent compound. The parent compound was also analysed in the influent and activated sludge. From Day 40 to 58 samples were taken to assess a mean of the removal percentage with organic carbon concentrations. All the validity criteria were fulfilled. During the last week of the test the parent compound in the effluent of the test unit was <10 µg/L corresponding with >99.98% removal. Analysis of the test substance present in the activated sludge demonstrated that approximately 99.98% of the test substance was removed by biodegradation.

Benzyl C12-16 alkyl dimethyl ammonium chloride is removed from waste water at very high percentages (approximately 99.98%) in the continuous activated sludge test. Test substance is expected to biodegrade almost completely in conventional biological waste water treatment plants (van Ginkel and Geerts, 2007).