Bis(2-chloroethyl) ether

Biodegradation in water and sediment: simulation tests

Administrative data

Endpoint:

biodegradation in water: sewage treatment simulation testing

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Justification for type of information:

Study conducted according to sound scientific principles. However, while the study has been peer-reviewed, it provides insufficient data to assess the reliability of the results.

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

1986

Reference 2

Reference Type:

publication

Title:

Unnamed

Year:

1988

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Alternative water treatment processes were compared to conventional activated sludge system in order to evaluate their relative efficiency to remove 21 listed organic priority pollutants (including Bis(2-chloroethyl)ether). The selected alternative processes were: single-stage high-rate trickling filter, primary treatment with chemical addition, direct filtration of primary effluent, aerated lagoons, and single-stage facultative lagoons. Influent wastewater was spiked with the 21 listed priority pollutants dissolved in toluene. Samples of feed, effluents, and sludges were analyzed for both conventional and priority pollutants.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Bis(2-chloroethyl) ether

EC Number:

203-870-1

EC Name:

Bis(2-chloroethyl) ether

Cas Number:

111-44-4

Molecular formula:

C4H8Cl2O

IUPAC Name:

1-chloro-2-(2-chloroethoxy)ethane

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: no data
- Expiration date of the lot/batch: no data
- Purity test date: no data


STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL: no data

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing:
- Preliminary purification step (if any):
- Final dilution of a dissolved solid, stock liquid or gel:
- Final preparation of a solid:

FORM AS APPLIED IN THE TEST (if different from that of starting material)

OTHER SPECIFICS:

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, adapted

Details on inoculum:

- Source of activated sludge : Raw wastewater from the Mill Creek Wastewater Treatment Plant located in the vicinity of the Water Engineering Research Laboratory at the Test and Evaluation (T&E) Facility, Cincinnati, Ohio.
- Biomass concentration of raw wastewater: BOD = 279 mg/L; TSS = 487 mg/L
- Pretreatment: Raw wastewater was diluted (1:1) with Mill Creek secondary effluent. Before mixing, the secondary effluent was passed throuh a bed of garnular activated carbon. The objective was to prepapre an inoculum more typical of domestic U.S. wastewater. Two steel columns 74 cm inside diameter (ID) and 3.7 m high, each containing 1.5 m depth of 8 X 30 mesh granular activated carbon were used to treat the Mill Creek secondary effluent. One column normally operated with the other in back wash or standby mode. The carbon was not regenerated during the 8-month study. An equal volume of coarse-screened raw wastewater was then mixed with the carbon column effluent.
- Spiking: the spiking solution containing the 21 priority organic pollutants dissolvec in toluenen was added to the preatreated inoculum in order to reach a concentration of 100 µg/L of each pollutant. The spiked wastewater contained 70 mg/L toluene.
- Equilibration: The spiked wastewater was passed through a static mixer into three closed detention tanks arranged in series to provide time for the priority pollutants to equilibrate with solids in the wastewater. Detention times ranged between 1.2 and 5.6 hours depending on the number of pilot systems in operation. To prevent solids from depositing in the detention tanks at low flows, effluent from the third tank was pumped through a recirculation line back to the first tank. The spiked equilibrated wastewater was pumped from the recirculation line to feed all systems.
- Acclimation: The four biological treatment systems were operated on spiked wastewater for 30 days before the first samples were collected in order to acclimate the biomass to the selected organic pollutants. The primary with chemical addition system and the high-flow direct filtration of primary effluent system were operated only during scheduled sampling periods to reduce the cost of spiking chemicals and associated labor in spike concentrate preparation.
- Biomass concentration (mg/L) used in test: no specified but said to be typical of domestic U.S. wastewater

Duration of test (contact time):

ca. 8 mo

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

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I. CONVENTIONAL ACTIVATED SLUDGE SYSTEM (= Control):
I.1. Test conditions
- Water flow: 8.2 m3/d (1.5 gpm).
- Return activated sludge (RAS): 2.7 m3/d (= 1/3 of the influent flow).
- Suspended solids concentration: The suspended solids concentra tions in the mixed liquor and RAS were approximately 2000 mg/L and 7000 mg/L, respectively.
- Nominal solid retention time: 7 days.
- Food-to-microorgansim ratio: 0.5 kg chemical oxygen demand (COD) per day per kilogram of mixed liquor suspended solids (MLSS).
I.2. Test System:
Primary clarifier:
- Circular stainless steel tank with a 45° conical bottom (inside diameter = 0.91 m; sidewater depth = 1.5 m).
- Inlet well: diamater = 0.3 m.
- Sludge collector speed = 5 rph.
- Clarifier overflow rate = 12.4 m3/m2/d.
- Hydraulic detention time = 3.2 h.
Aeration basin:
- Five-pass rectangular, stainless steel tank (length = 3.05 m; width = 0.61 m; sidewater depth = 1.37 m).
- Residence time = 7.5 h.
Final clarifier:
- Identical to the Primary Clarifier.
I.3. Test system efficiency (on average):
TSS: 93%; Total COD: 82%; Dissolved COD: 69%; Ammonia: 86%; Total Kjeldahl nitrogen (TKN): 80%; Total phosphorus: 58%.

II. HIGH RATE TRICKLING FILTER SYSTEM:
II.1. Test conditions
- Water flow: 8.2 m3/d (1.5 gpm).
- Return flow: 8.2 m3/d (i.e., 100% of the design wastewater flow).
- Surface application rate to the filter: 12.4 m3/m2/d.
- Application rate for the volume of media: 6.6 m3/m3/d.
II.2. Test System:
Primary clarifier: identical to that of the conventional activated sludge system.
Trickling filter system:
- Circular stainless steel tank (height= 2.4 m; Inner diameter = 0.91 m).
- Content: 1.9 m of 3.8 to 7.6 cm crushed slag media.
- Primary effluent and return flow from the bottom of the trickling filter are applied to the media from a motor-driven rotating distributor arm.
Final clarifier: identical to that of the conventional activated sludge system.
II.3. Test system efficiency (on average):
TSS: 76%; Total COD: 47%; Dissolved COD: 26%; Total Kjeldahl nitrogen (TKN): 14%; Total phosphorus: 39%.

III. PRIMARY TREATMENT WITH CHEMICAL ADDITION:
III.1. Test conditions:
- Water flow: 10.9 m3/d (2 gpm).
III.2. Test System:
- Rapid-mix tank (Stainless steel; Inner diameter: 29.5 cm; Liquid depth: 8.9 cm; Detention time: 48 s) equipped with a propeler mixer where alum solution (19 g/L) is flash-mixed with the wastewater (250 mg alum /L of wastewater.
- Rectangular flocculation tank (Width: 0.6 m; Length: 1.6 m; Water depth: 0.4 m; Detention time: 53 min) equipped with two paddle stirrers where gentle agitation produces a settleable floc.
- Final clarifier tank (Inner diameter: 0.95 m; sidewater depth: 1.45 m; Overflow rate: 15.2 m3/d) where the solids are separated from the wastewater.
III.3. Test system efficiency (on average):
TSS: 89%; Total COD: 49%; Dissolved COD: 2%; Total Kjeldahl nitrogen (TKN): 12%.

IV. DIRECT FILTRATION OF PRIMARY EFFLUENT:
IV.1. Test conditions:
- No data
IV.2. Test system:
- Production of primary effluent: spiked wastewater is passed through a circular steel tank (Inner diameter = 2.3 m ID; sidewater depth: 2.7 m; detention
time = 3.9 hours; overflow rate = 17.0 m3/m2 d; wastewater flow = 69.8 m3/d (12.8 gpm)).
- Filtration: commercial pulsed-bed pilot unit (filter: 0.25 m bed of 0.35 mm sand as media; surface loading: 54.5 m3/d; flow: 147 m3/m2/day).
IV.3. Test system efficiency (on average):
TSS: 86%; Total COD: 40%; Total Kjeldahl nitrogen (TKN): 15%; Total phosphorus: 44%.

V. LAGOON SYSTEMS:
V.1. Test conditions:
- Light: 5000°K fluorescent lamps suspended 1.8 m above the water surface (light intensity not specified).
- Light cycle: 14L/8D.
- Feeding of lagoons: facultative lagoon = 0.19 m3 wastewater/d; aerated laggon: 4 x 0.19 m3 wastewater/d.
- Hydraulic detention time: facultative lagoon = 25.6 d; aerated laggon: 6.4 d.
- Dissolved oxygen concentrations: 0.1 to 0.2 mg/L
V.2. Test system:
- Aerated and facultative lagoons: sections of concrete pipe (Inner diameter = 2.3 m; sidewater depth = 1.2 m; surface area: 4.1 m2; wasterwater volume: 4.8 m3 each).
V.3. Test system efficiency (on average):
- Facultative lagoon: TSS: 84%; Total COD: 65%; Dissolved COD: 42%; Total Kjeldahl nitrogen (TKN): 11%; Total phosphorus: 31%.
- Aerated lagoon: TSS: 85%; Total COD: 60%; Diossolved COD: 42%; Total Kjeldahl nitrogen (TKN): 2%; Total phosphorus: 19%.

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SAMPLING:
- Priority pollutants samples: Samples were collected for 2 or 3 consecutive days at approximately 6-week intervals; Grab samples for volatile analysis were collected three times per day in screw-cap glass vials with an inert fluorocarbon polymer-lined septum; Samples were mixed to obtain a daily composite sample. Samples were collected six times per day and composited into one daily sample for semivolatile organics.
- Conventional pollutants samples: 24 hour composite samples were obtained from grab samples collected six times per day; frequency: every other day.
- pH and lakalinity: 3 times per day.
- TSS: daily.
- Samples storage: refrigerated at 4°C until analyzed (addition of preservatives if applicable).

Results and discussion

% Degradation

% Degr.:

>= 64 - <= 80

Parameter:

test mat. analysis

Remarks on result:

other: Activated sludge system

Transformation products:

not measured

Evaporation of parent compound:

not measured

Volatile metabolites:

not measured

Residues:

not measured

Any other information on results incl. tables

Table 1. Concentrations of BCEE in waste water feed and effluents and removal by different processes (results from Hannah et al. 1986).

	Concentration in BCEE (µg/L)		% removal
	Mean	Standard dev.	Mean	Standard dev.
Wastewater feed	143	51	-	-
Activated sludge*	30	48	80	31
Primary clarification*	122	37	6	27
Primary plus filtration*	120	26	20	28
Chemical clarification*	114	53	17	40
Trickling filter*	132	37	-1	16
Aerated lagoon*	201	41	23	31
Facultative lagoon*	78	28	43	14

* secondary effluent

Table 2. BCEE removal by different processes (results from Hannah et al. 1988).

	Concentration in BCEE (µg/L)		% removal
	Mean	Standard dev.	Mean	Standard dev.
Wastewater feed	ns	ns	-	-
Activated sludge*	74	82	64	38
Trickling filter*	148	65	ns	ns

ns: not specified

* secondary effluent

Applicant's summary and conclusion

Validity criteria

Validity criteria fulfilled:

not applicable

Conclusions:

Based on a conventional activated sludge treatment, the removal efficiency of Bis(2-chloroethyl) ether was found to vary between 64 +/-38% and 80 +/- 31%.

Executive summary:

In this peer-reviewed publication (Hannah et al. 1986), the removal of various priority organic pollutants was assessed using different water treatment setups (conventional activated sludge, sand filtration, chemical clarification, trickling filter and aerated or facultative lagoons). The activated sewage sludges were acclimated for 30 days to the priority organic pollutants. Samples were collected daily for 2-3 days at 6 week intervals for c.a. 8 months. The conventional activated sludge treatment, showed the highest efficiency Bis(2-chloroethyl) ether, which achieved 80 +/- 31%. In a sister study (Hannah et al. 1988), the same experimental setup only achieved a removal efficiency of 64 +/- 38% despite the best efforts to hold experimental conditions at a steady state.