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EC number: 231-820-9 | CAS number: 7757-82-6
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Toxicity to microorganisms
Administrative data
- Endpoint:
- toxicity to microorganisms
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Literature data
Data source
Reference
- Reference Type:
- publication
- Title:
- The effect of inorganic salts on the activated sludge process performance
- Author:
- Tokuz Yucel R. and Eckenfelder Wesley W. Jr.
- Year:
- 1 978
- Bibliographic source:
- Water Research Vol. 13. pp. 99 to 104. Pergamon Press Ltd 1979. Printed in Great Britain
Materials and methods
- Principles of method if other than guideline:
- 37 days test with increasing concentration. The procedure for the test were the same as described in the Standard Methods (1971).
- GLP compliance:
- not specified
Test material
- Reference substance name:
- Sodium sulphate
- EC Number:
- 231-820-9
- EC Name:
- Sodium sulphate
- Cas Number:
- 7757-82-6
- Molecular formula:
- H2O4S.2Na
- IUPAC Name:
- disodium sulfate
Constituent 1
Test organisms
- Test organisms (species):
- activated sludge of a predominantly domestic sewage
- Details on inoculum:
- - Source: the activated sludges were taken from a local municipal wastewater treatment plant.
- Acclimatation: activated sludge were acclimated to the substrate for a period of over a month.
- Feeding: the food to micro-organism ratio (F/M ratio) was approximately 0.3 mg COD/day/mg Mixed Liquor Volatile Suspended Solids (MLVSS) at the start of the experiments. The hydraulic detention time was about 2 days. Since mixed liquor solids has built up as substrate TDS level increased and since hydraulic detention time was not modified, the food to microorganism ratio decreased to about 0.1 gradually.
Study design
- Test type:
- static
- Water media type:
- freshwater
- Total exposure duration:
- 37 d
Test conditions
- Test temperature:
- Kept at 20.5 ± 2°C
- Dissolved oxygen:
- The dissolved oxygen level in the reactors were maintained at about 8 mg/L and never dropped below 6 mg/L.
- Details on test conditions:
- TEST SYSTEM
- No. of replicate: three continuous flow activated sludge units were used.
- Unit volume: the total volume of each unit was 10 L of which 8 L were aeration chamber and 2 L settling basin.
No attempt was made to maintain the F/M ratio at 0.3 by wasting sludge (only wastage occurred when samples were collected for analysis), because of the problems encountered with 'deflocculating' sludge and resulting solid losses at the initial phases of the experiments. At such instances the sludge was highly dispersed and would not settle, resulting in large decreases in the concentration of sludge under aeration.
OTHER TEST CONDITIONS
Routine analyses on the cliluent included so!uble chemical oxygen demand, total suspended solids (TSS) and volatile suspended solids (VSS) determinations were performed.
Mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids were also determined daily.
Oxygen uptake rate was determined using a membrane electrode (YSI model 54A Oxygen meter, Yellow Springs Instrument Co., Yellow Springs, Ohio, U.S.A.).
- BOD of the substrate: 400 mg/L
- COD of the substrate: 1050 mg/L
Results and discussion
Effect concentrationsopen allclose all
- Duration:
- 37 d
- Dose descriptor:
- other: NOAEL
- Effect conc.:
- ca. 8 g/L
- Basis for effect:
- other: based on stalked ciliatcs
- Duration:
- 37 d
- Dose descriptor:
- other: NOAEL
- Effect conc.:
- ca. 26 g/L
- Basis for effect:
- other: based on motile protozoa
- Details on results:
- The decrease in salinity from 25 g/L sodium chloride to less than 8 g/L improved the effluent quality greatly and subsequent switch to sodium sulphate did not cause any upset on the system even up to 30 g/L sodium sulphate concentration. The effluent remained clear and the COD removal efficiency was the same as the control unit.
Upon examination under a microscope it was observed that high salt concentrations caused filamentous micro-organisms to appear.
In the sodium sulphate system stalked ciliatcs disappeared early but even at 26 g/L sodium sulfate level, motile protozoa were observed.
The abundance of filamentous micro-organisms on the other hand did not affect the floc formation and ettling capacity of the sludge.
Applicant's summary and conclusion
- Conclusions:
- NOAEL at 37 days = 26 g/L based onmotile protozoa
NOAEL at 37 days = 8 g/L based onstalked ciliatcs - Executive summary:
The effect of inorganic salt sodium sulphate on the performanceof the activated sludge process was examined. Test was performed in 37 days, increasing concentration and the procedure for were the same as described in the Standard Methods (1971).
Conclusion
The effect of sodium sulphate on the system was low.
NOAEL at 37 days = 26 g/L based onmotile protozoa
NOAEL at 37 days = 8 g/L based onstalked ciliatcs
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