Methenamine

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

publication

Title:

Biodegradation of formaldehyde and its derivated in industial watewater with methylotrophic yeast Hansenula polymorpha and with the yeast-bioaugmented activated sludge

Author:

Kaszycki, P.; Koloczek, H.

Year:

2002

Bibliographic source:

Biodegradation 13 : 91-99, 2002

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Methenamine

EC Number:

202-905-8

EC Name:

Methenamine

Cas Number:

100-97-0

Molecular formula:

C6H12N4

IUPAC Name:

1,3,5,7-tetraazatricyclo[3.3.1.1³,⁷]decane

Details on test material:

1) Methenamine waste water from industrial plan (pH 7.8, COD = 11309 mg/L, formaldehyd + methenamine c = 2300 mg/L, monomeric formaldehyde C= 582 mg/L, methanol C= 2980 mg/L)
2) Pure methenamine solution (1600 mg/L)

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
1) pH 7.8

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, adapted

Details on inoculum:

The study included several independent activated sludge samples collected at aeration chambers of biological wastewater treatment stations of different chemical plant. As an additional reference in yeast integration experiments, the activated sludge from a typical minicipal household wastewater treatment station was also used. Theactivated sludge was applied in experiments within two weeks of collection. The sludge was stored at 4°C and upon experiment, it was reactivated by placing 50-100 ml suspension in a 250 ml flask ans by aerobically cultivationg in a rotary shaker for 48 h at room temperature. Integration of the activated sludge with H. polymorpha was performed by adding the appropriate number of yeast cells to 20-50 mL of the sludge suspension and by cultivating the mixture under aerobic conditions for 24 h at 25°C.

Duration of test (contact time):

ca. 48 h

Initial test substance concentration

Initial conc.:

ca. 2 300 mg/L

Based on:

other: bound and anbound formaldehyd (mainly methenamine) in wastewater experiments

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

1) Measurement of methenamin in wastewater
2) Measurement of pure methenamine

Reference substance

Reference substance:

other: no data

Results and discussion

Preliminary study:

no data

Test performance:

A good test performance was documented.

% Degradation

% Degradation 1

Parameter:

% degradation (test mat. analysis)

Value:

ca. 9

Sampling time:

48 h

Remarks on result:

other: Wastewater, pH 8.1

% Degradation 2

Parameter:

% degradation (test mat. analysis)

Value:

ca. 74

Sampling time:

48 h

Remarks on result:

other: Wastewater, pH 4.5

Details on results:

1) Wastewater:
Very poor degradation with H. polymorpha at high ph values of 8.1. At lower pH (4.5) a degradation of 74% was observed.
2) Pure methenamine:
In a model system at pH 5.3, H. polymorpha dens culture (at about 10(exp 7) cells/mL) was able to biodegrade methenamineat initial concentrations up to 1600 mg/L to about 44%.

BOD5 / COD results

Results with reference substance:

no reference substance

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Interpretation of results:

readily biodegradable

Conclusions:

Methenamine is biodegradable in wastewater at low pH conditions.

Executive summary:

Methenamine biodegrandation was measured in wastewater containing high amounts of metheamine, formaldehyde and methanol and also in a model system using pure methenamine. The measurement was done at different pH values, by determining the methenamin concentrations colorimentrically after 48 h incubation.

Results:

- Wastewater: Very poor degradation with H. polymorpha at high ph values of 8.1. At lower pH (4.5) a degradation of 74% was observed.

- Pure methenamine: In a model system at pH 5.3, H. polymorpha dens culture (at about 10(exp 7) cells/mL) was able to biodegrade methenamineat initial concentrations up to 1600 mg/L to about 44%.

Thus, methenamine can be regarded biodegradable in wastewater at low pH conditions.