Number

315-EN

Section

General Section

Use

Abstract

Chitosan is a material obtained from biological (non-petroleum) sources and can be used to substitute polyacrylamide and other synthetic polymers flocculants in various applications.

Substituted substances

Alternative Substances

Reliability of information

Internet information: data are from an internet document and only a basic and partial evaluation could be performed

Reason substitution

CMR
neurotoxicant
skin/respiratory sensitizing

Hazard Assessment

Substance to be substituted: Polyacrylamide is not listed in the SUBSPORTplus Database and has no harmonised classification according to Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation). Alternative substance: Chitosan has no harmonised classification according to Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation) and is not listed in the Substance Database according to SUBSPORTplus Screening Criteria (SDSC). It is obtained from biological sources mainly resulted as waste in the processing of shrimps.

Description of Substitution

Chitosan is a polymer obtained from chitin, a natural biopolymers, such as cellulose and starch. Chitin is present in certain crustaceans and insects, as well as in the cell of fungi. Economical quantities are produced from shell material from the processing of crabs, prawns and shrimps. Chitosan is already used internationally in various applications, such as drinking and waste water treatment, separation of oil-water-mix ,heavy metal separation etc. Being a cationic polymer chitosan is suitable for the flocculation of micro-organisms with anionic surface charge, therefore also for municipal sludge, preferable for activated sludge thickening. According to the producer the advantages of chitosan in this application are: •biodegradable, non-toxic (water hazard classification 0 according to German classification) •a good and fast dewatering of sludge •a higher dry matter content and •a highly reduced adhesive effect on filter tissues. •recycling of sludge is possible. The disadvantages are a higher price than for polyacrylamide and a reduced stability of the flock for sludge dewatering in decanters. Work is carried on to improve stability and reduce costs by combining chitosan to other bio copolymers.

Case/substitution evaluation

Polyacrylamide is obtained from petroleum sources and, though it is not toxic in itself, it may decompose in the environment, resulting in the release of its monomer, acryl amide, a known carcinogen. The substitution is easy to implement. The fact that chitosan polymers still cost more than polyacrylamide is a disadvantage. However the treated sludge may be used in agriculture, because of its low toxicity and biodegradability, which is a more economic and environmentally friendly alternative to other methods like sludge incineration.

State of implementation

In use

Date and place of implementation

Germany

Enterprise using the alternative

http://www.biolog-heppe.de

Availability ofAlternative

The alternative is available on the market.

Type of information supplier

Producer / distributor

Contact

http://www.biolog-heppe.de

Further information

Chitosan MSDS from Sigma Aldrich

Publication source: author, company, institute, year

The presentation is based on the description published by the producer on its website http://www.biolog-heppe.de/

Publication source

Type of publication and availability

https://www.biolog-heppe.de/chitosan/gb/6712,,/index.html

Date, reviewed

November 26, 2021