Ultimate and Primary Biodegradation of a Range of Nonpolymeric and Polymeric Surfactants in Seawater.

Surfactants are chemicals commonly used in a wide range of domestic and industrial products. In the present study, ultimate biodegradation of 18 surfactants representing different classes (including several polymeric alcohol ethoxylates [AEs]) was determined in seawater at 20 °C by a Closed Bottle test method. After 28 days of incubation, 12 surfactants reached 60% biodegradation and were considered to be readily biodegradable in seawater.

Accurate assessment of the biodegradation of cationic surfactants in activated sludge reactors (OECD TG 303A).

The continuous-fed activated sludge test (OECD TG 303A) was used to predict the removal of cationic surfactants from wastewater in activated sludge plants. However, a method to differentiate between adsorption and biodegradation is not provided in these guidelines. Assessment of removal by biodegradation was possible with analysis of the surfactant present in mixed liquid suspended solids in combination with a simple equation.

Microorganisms hydrolyse amide bonds; knowledge enabling read-across of biodegradability of fatty acid amides.

To get insight in the biodegradation and potential read-across of fatty acid amides, N-[3-(dimethylamino)propyl] cocoamide and N-(1-ethylpiperazine) tall oil amide were used as model compounds. Two bacteria, Pseudomonas aeruginosa PK1 and Pseudomonas putida PK2 were isolated with N-[3-(dimethylamino)propyl] cocoamide and its hydrolysis product N,N-dimethyl-1,3-propanediamine, respectively. In mixed culture, both strains accomplished complete mineralization of N-[3-(dimethylamino)propyl] cocoamide.

Effect of long-term cobalt deprivation on methanol degradation in a methanogenic granular sludge bioreactor.

The effect of the trace metal cobalt on the conversion of methanol in an upflow anaerobic sludge bed (UASB) reactor was investigated by studying the effect of cobalt deprivation from the influent on the reactor efficiency and the sludge characteristics. A UASB reactor (30 degrees C; pH 7) was operated for 261 days at a 12-h hydraulic retention time (HRT). The loading rate was increased stepwise from 2.