N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine

Biodegradation in water and sediment: simulation tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: sewage treatment simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 17 January 2007 to 21 May 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.10 (Biodegradation: Activated Sludge Simulation Test)

Version / remarks:

Cited as Directive 88/302/EEC, C.10

Deviations:

yes

Remarks:

minor deviations which did not affect the outcome of the study

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

INOCULUM/TEST ORGANISM:
- Type of sludge: Activated sludge from a plant treating predominantly domestic wastewater
- Source: Wastewater treatment plant (WWTP) Nieuwgraaf in Duiven, The Netherlands (17-01-2007)
- Preparation of inoculum: The primary settled sewage was collected weekly and stored in the refrigerator until required.
- Pretreatment: Test units were preconditioned for one week
- Initial cell concentration: 300 mL of secondary activated sludge containing approximately 3 g/L dry weight was used as an inoculum for each CAS unit.

Duration of test (contact time):

58 d

Initial conc.:

50 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

other: Non purgeable organic carbon (NPOC)

Details on study design:

TEST SYSTEM
- Culturing apparatus: The CAS test was performed in a Husmann-type units constructed of glass. The units consisted of an aeration vessel capable of holding 0.35 L from which the liquor was passed continuously to a settler of 0.3 L capacity. The domestic waste water liquor in a vessel cooled with ice was supplied with a pump. The liquor passed through the aeration vessel and settler and treated effluent left the apparatus to be collected in a vessel. Aeration was achieved through a capillary on the bottom of the aeration section at a rate of approximately 9 L/h air. Sludge accumulating around the top of the aeration vessel was returned in the system once a day by brushing.
- Number of culture flasks per concentration: Two (control and test)
- Aeration device: Capillary on the bottom of the reactor
- Measuring equipment: The non purgeable organic carbon (NPOC) in acidified filtered samples were analysed in a TOC apparatus (Shimadzu, s'Hertogenbosch, The Netherlands).
- The chemical oxygen demand (COD) of the influent and effluent was determined by oxidation with an acid-dichromate mixture in which Cr6+ was reduced to Cr3+ (Hach Lange, Duesseldorf, Germany).
- The dissolved oxygen concentrations were determined electrochemically using an oxygen electrode (WTW Trioxmatic EO 200) and meter (WTW OXI 530) (Retsch, Ochten, The Netherlands).
- The pH was measured using a Knick 765 calimatic pH meter (Elektronische Messgerate GmbH, Berlin, Germany).
- The temperature was measured with a Tegam thermometer Model 820 (Applikon, Schiedam, The Netherlands).
- The dry weight (DW) of the inoculum was determined by filtering the activated sludge over a pre weighed 12 µm Schleicher and Schüll filter. This filter was dried for 1.5 h at 104°C and weighed after cooling. DW was calculated by subtracting the weighed filters and by dividing this difference by the filtered volume.
- Closed vessels used: No

INITIAL TEST SUBSTANCE CONCENTRATION: 48-51 mg/L

METHOD OF PREPARATION OF TEST SOLUTION: A solution of the test substance of 7.3 g/L in deionized water was directly added to the test unit using a syringe pump. The flow rate of the syringe pump was ~9.6 mL/day giving a calculated concentration of the test substance in the influent of the unit
of 48-51 mg/L.

DURATION OF THE TEST: 58 d

ANALYTICAL PARAMETER: Non purgeable organic carbon (NPOC)

SAMPLING: From Day 40 to 58 samples were taken to assess a mean of the removal percentage with NPOC contents.

TEST CONDITIONS :
- Composition of medium: Domestic wastewater contain organic compounds
- Additional substrate: No
- Test temperature: 19-21°C
- pH value: 7.0 - 8.0
- Concentration of suspended solids: 2 - 3 g/L

CONTROLS: Unit fed with domestic wastewater

REFERENCE SUBSTANCE: Reference substance is not tested (not required)

Reference substance:

not required

Key result

% Degr.:

99.86

St. dev.:

0.003

Parameter:

test mat. analysis

Sampling time:

58 d

Remarks on result:

other: the percentage degradation is an average of 5 consecutive days (Days 55 - 59)

Remarks:

(Removal of the test substance from the influent through adsorption onto sludge was only 0.11 to 0.14% at Day 57 and 58, respectively, demonstrating that the substance was primarily removed by biodegradation)

Transformation products:

no

Remarks:

Substance is readily biodegradable

Details on transformation products:

No soluble transformation products formed; 99.4% NPOC removal.

Evaporation of parent compound:

no

Volatile metabolites:

no

Residues:

no

Details on results:

- Based on the results of the ready test the test substance was completely metabolized to CO2, H2O and NH4/NO3 (no intermediates formed).

Details on results:
From day 40 to 58 samples were taken to assess a mean of the removal percentage with NPOC contents. According to the Dixon test, there were no outliers during this period. Subsequently, all data were used in a t-statistic.
- The mean difference between the NPOC in the influent and effluent was 0.21 ± 0.86 mg/L (95 per cent confidence interval).
- The mean removal percentage calculated with this mean difference was 99.4 ± 2.4 (95% confidence).
- The t-statistic (n = 15) did not exceed the critical value and the mean difference is therefore not statistically significant.
The results therefore demonstrated that the continuous activated sludge system treating domestic wastewater spiked with the test substance removes the organic carbon of the test substance almost completely or completely from waste-water. The high carbon removal percentages also demonstrate that recalcitrant water-soluble substances are not formed during the biodegradation process.

During the last week of the test the parent compound in the effluent of the test unit was <10 µg/L corresponding with >99.995% removal. Analysis of the test substance present in the activated sludge was measured on Day 57 and 58 and the results of the specific chemical analysis showed that only 0.14% of the nominal influent concentration is removed by sorption and that thus ~99.86% of the test substance was removed by biodegradation.
More details on calculating the fraction biodegraded in an OECD 303A study is described in Geerts et al., 2015 Accurate assessment of the biodegradation of cationic surfactants in activated sludge reactors Ecotoxicology and Environmental Safety 118 (2015)83–89

The performance of the control unit was checked (Day 14 and the last day of the test) by measuring the COD removal (Day 14 and the last day of the test) and the concentrations of ammonium and nitrite in the effluent (Day 14).
- At day 14 the COD in the influent and effluent were 517 and 55 mg/L, respectively.
- At the last day the COD in the influent and effluent were 548 and 47 mg/L, respectively.
- The COD removal percentages were 89 and 91.
- The ammonium and nitrite concentrations in the effluent at Day 14 were <2.5 and <2.0 mg/L.
These results demonstrate that the test is valid.

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the test substance was found to be removed predominantly by biodegradation at very high percentages (99.9% on Day 58) and to a lesser extent by sorption (0.11 - 014 %)

Executive summary:

A study was conducted to determine the biodegradation of the test substance in an activated sludge simulation test according to EU Method C.10, in compliance with GLP. A solution of 7.3 g/L of substance in deionized water was directly added to the test unit using a syringe pump. The flow rate of the pump was ca. 9.6 mL/day giving a calculated concentration of the test substance in the influent of the unit of ca. 50 mg/L. The domestic sewage supply was supplied at a rate of approximately 1.4 L/day to give a hydraulic retention time of 6 h. The CAS tests were operated between 2 and 3 g/L dry weight of sludge. From Day 40 to 58, samples were taken to assess a mean of the removal percentage with non purgeable organic carbon (NPOC) content. During the last week, the parent compound was also analysed in the influent and activated sludge. There were no outliers during this period. Subsequently, all data was used in a T-statistic. The mean difference between the NPOC in the influent and effluent was 0.21 ± 0.86 mg/L (95% confidence interval). The mean removal percentage calculated with this mean difference was 99.4 ± 2.4 (95% confidence interval). The T-statistic (n = 15) did not exceed the critical value and the mean difference is therefore not statistically significant. The results therefore demonstrated that the continuous activated sludge system treating domestic wastewater spiked with the test substance removed the organic carbon of the test substance almost completely or completely from wastewater. The high carbon removal percentages also demonstrated that recalcitrant water-soluble substances were not formed during the biodegradation process. During the last week (Days 55 - 59), the parent compound in the effluent of the test unit was 10 μg/L, corresponding with 99.995% removal. Analysis of the test substance present in the activated sludge on Days 57 and 58 showed that only 0.11 - 0.14 % of the test substance was removed by sorption. The performance of the control unit was checked by measuring COD removal (Day 14 and the last day of the test) and the concentrations of ammonium and nitrite in the effluent (Day 14). On Day 14, the COD in the influent and effluent was 517 and 55 mg/L, respectively. On the last day, the COD in the influent and effluent was 548 and 47 mg/L, respectively. The COD removal was 89 and 91%. The ammonium and nitrite concentrations in the effluent on Day 14 were 2.5 and 2.0 mg/L. These results demonstrated that the test was valid. Under the study conditions, the test substance was found to be removed predominantly by biodegradation at very high percentages (99.9% on Day 58) and to a lesser extent by sorption (0.11 - 014%) (van Ginkel, 2007).

Reference 2

Endpoint:

biodegradation in water: sewage treatment simulation testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Principles of method if other than guideline:

Two 1 gallon jugs, with gas trapping systems, containing 2 litres of either biotic or abiotic activated sludge, were dosed with radiolabelled test substance.
The activated sludge was collected from the Denton Wastewater Treatment Facility, Denton, Maryland and was maintained in a porous pot bioreactor during acclimation. The porous pot bioreactor is designed to simulate the activated sludge sewage treatment process and is a glass vessel that houses a porous polyethylene membrane (pore size approximately 35 μm) that retains the sludge solids but allows liquid to flow through the system. The hydraulic retention time (HRT) was controlled by the feed rate using low-volume pumps and was maintained at approximately 8 h. Sludge retention time (SRT) was controlled by removing sludge solids from the bioreactor and was maintained at approximately 10 d. The bioreactor was continuously dosed at a nominal influent concentration of 150 μg/L. In addition, domestic sewage was continuously added to the bioreactor to provide the necessary nutrients required for bacterial metabolism.

GLP compliance:

yes

Radiolabelling:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Duration of test (contact time):

28 d

Initial conc.:

16 µg/L

Based on:

test mat.

Key result

% Degr.:

73.84

Parameter:

CO2 evolution

Sampling time:

28 d

Key result

Compartment:

entire system

DT50:

ca. 7 d

Type:

(pseudo-)first order (= half-life)

Temp.:

20 °C

Transformation products:

not specified

Validity criteria fulfilled:

not applicable

Conclusions:

Under the study conditions, the test substance biodegraded in aerobic conditions and mineralised up to 70% on day 28 (detection via 14CO2).

Executive summary:

A study was conducted to evaluate the ready biodegradability of the test substance using the porous pot bioreactor simulation system of a non-adapted, activated and domestic sludge sewage treatment process. The reactor was built from a glass vessel that housed a porous polyethylene membrane (pore size approximately 35 μm) and retained sludge solids but allowed liquid to flow through the system. This study was performed in order to evaluate the aerobic elimination and degradation potential of the test substance throughout a 28 d period using a test substance concentration of 16 µg/L. Under the study conditions, the test substance biodegraded in aerobic conditions and mineralised up to 70% on Day 28 (detection via 14CO2) (Schaefer, 2003).

Description of key information

Under the study conditions, the test substance was found to be removed predominantly by biodegradation at very high percentages (99.9% on Day 58) and to a lesser extent by sorption (0.11 - 014 %)

Additional information

Activated sludge simulation test

A study was conducted to determine the biodegradation of the test substance in an activated sludge simulation test according to EU Method C.10, in compliance with GLP. A solution of 7.3 g/L of substance in deionized water was directly added to the test unit using a syringe pump. The flow rate of the pump was ca. 9.6 mL/day giving a calculated concentration of the test substance in the influent of the unit of ca. 50 mg/L. The domestic sewage supply was supplied at a rate of approximately 1.4 L/day to give a hydraulic retention time of 6 h. The CAS tests were operated between 2 and 3 g/L dry weight of sludge. From Day 40 to 58, samples were taken to assess a mean of the removal percentage with non purgeable organic carbon (NPOC) content. During the last week, the parent compound was also analysed in the influent and activated sludge. There were no outliers during this period. Subsequently, all data was used in a T-statistic. The mean difference between the NPOC in the influent and effluent was 0.21 ± 0.86 mg/L (95% confidence interval). The mean removal percentage calculated with this mean difference was 99.4 ± 2.4 (95% confidence interval). The T-statistic (n = 15) did not exceed the critical value and the mean difference is therefore not statistically significant. The results therefore demonstrated that the continuous activated sludge system treating domestic wastewater spiked with the test substance removed the organic carbon of the test substance almost completely or completely from wastewater. The high carbon removal percentages also demonstrated that recalcitrant water-soluble substances were not formed during the biodegradation process. During the last week (Days 55 - 59), the parent compound in the effluent of the test unit was 10 μg/L, corresponding with 99.995% removal. Analysis of the test substance present in the activated sludge on Days 57 and 58 showed that only 0.11 - 0.14 % of the test substance was removed by sorption. The performance of the control unit was checked by measuring COD removal (Day 14 and the last day of the test) and the concentrations of ammonium and nitrite in the effluent (Day 14). On Day 14, the COD in the influent and effluent was 517 and 55 mg/L, respectively. On the last day, the COD in the influent and effluent was 548 and 47 mg/L, respectively. The COD removal was 89 and 91%. The ammonium and nitrite concentrations in the effluent on Day 14 were 2.5 and 2.0 mg/L. These results demonstrated that the test was valid. Under the study conditions, the test substance was found to be removed predominantly by biodegradation at very high percentages (99.9% on Day 58) and to a lesser extent by sorption (0.11 - 014%) (van Ginkel, 2007).

 

Activated sludge porous pot bioreactor simulation system

A study was conducted to evaluate the ready biodegradability of the test substance using the porous pot bioreactor simulation system of a non-adapted, activated and domestic sludge sewage treatment process. The reactor was built from a glass vessel that housed a porous polyethylene membrane (pore size approximately 35 μm) and retained sludge solids but allowed liquid to flow through the system. This study was performed in order to evaluate the aerobic elimination and degradation potential of the test substance throughout a 28 d period using a test substance concentration of 16 µg/L. Under the study conditions, the test substance biodegraded in aerobic conditions and mineralised up to 70% on Day 28 (detection via 14CO2) (Schaefer, 2003).