Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 215-686-9 | CAS number: 1344-08-7
Biodegradation in water and sediment: simulation tests
Administrative data
Link to relevant study record(s)
Description of key information
The degradation rate for polysulfides in water and sediment is estimated using the default value according to the TGD.
Articles published in peer reviewed journals are used to show that the removal of sulfide in biological treatment systems is also representative for thepolysulfide removal. Exampels of sulfide removal in different reactor types / treatment systems are given.
Key value for chemical safety assessment
Additional information
Half life in water and sediment
Experimental data on the biodegradation in water and sediment of polysulfides are not available. The degradation rate is therefore estimated using the default value according to the TGD, assuming that no degradation takes place in the bound phase.Microorganisms are capable of growth on polysulfides in the presence (aerobic) and absence (anaerobic conditions) of oxygen. Therefore the same degradation rate is used for the aerobic sediment layer and the anaerobic bulk sediment.
The partitioning of polysulfides in sediment was calculated using the default Koc for Non-hydrophobics. Based on this Koc a partitioning coefficients for sediment Kp sed = 1.7 L/kg was calculated (EUSES 2.1.1; Kolck 2010). The suggested half-life for a readily degradable substance with a Kpsed in the range ≤100 l/kg is 30 days for the aerobic sediment layer and the anaerobic bulk sediment.
Biological wastewater treatment.
Biological treatment of hydrogen sulfide is widely used due to efficient conversion. In these treatment systems, sulfide is oxidized by microorganisms to for instance elemental sulfur or sulfate. The biodegradation kinetics of polysulfide and sulfide are comparable because both substances are metabolized by chemolithoheterotrophic and chemolithoautotrophic bacteria at acidic, neutral and alkaline conditions. The chemical oxidation of polysulfide is high compared to sulfide oxidation at slightly alkaline conditions. The removal of sulfide in biological treatment systems is therefore also representative for polysulfides.
Removal of sulfide with oxygen as oxidizing agent has been investigated in three reactor types i.e. a continuously stirred tank reactor with polyurethane particles as carrier material, a biorotor with polyurethane particles and an fixed film submerged up-flow reactor also with polyurethane particles. The fixed film submerged up-flow reactor and biorotor performed best. At hydraulic retention times of < = 1 h removal percentages of > 90% were achieved (Buisman et al, 1989). Sublette (1987) cultured Thiobaccillus denitrificans aerobically in a continuous flow reactor and found 100% removal of sulfide. Biological treatment of sulfide in a reverse fluidized loop reactor allowed 90 to 100% of sulfide removal from wastewater. This reactor was operated aerobically with an hydraulic retention time of only 90 minutes (Krishnakumar et al, 2005).
In a pilot-scale plant sulfide-containing wastewater from petrochemical industries was treated using autotrophic denitrifying bacteria. Denitrification is nowadays also widely used in publicly owned wastewater treatment plants. The hydraulic retention time in the reactor was only 0.5 days. A removal of >99% of the sulfide was found in the reactor fed with influent containing sulfide concentrations of up to 110 mg/L (Vaiopoulou et al, 2005).
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
