Case Study #274
1. Headline: Internal recycling at a French dye and enamel
manufacturer reduces waste water problems.
2. Background: The firm CERDEC uses metal oxides to
manufacture dyes and enamels. They wish to recover cadmium
and selenium from the factory's waste water. This case
study was carried out in 1993.
3. Cleaner Production Principle: Internal recycling
4. Description of Cleaner Production Application:
Information about the process and wastes
Upon request of CERDEC, trials were carried out in order
to reuse effluents, with selective recovery of selenium
and cadmium, and then final treatment of the effluent in
the existing treatment plant.
In the manufacturing process, pigments are subject to
pickling in a hydrochloric medium, followed by washing and
filtration on a belt filter. The concentrated effluents
produced are stored in 2 tanks of 25 m3, where they are
neutralized with sodium carbonate before conveyance to a
treatment centre.
Laboratory experiments showed the feasibility of a
removal/recovery of cadmium in the form of hydroxide
precipitate and of selenium by reduction/precipitation.
It is now a question of assessing the process from an
industrial and economical point of view, and showing that
it is possible to respect the discharge standards : 0.2
mg/l for selenium and cadmium.
A study of the different possibilities for recycling the
precipitates will follow.
5. Economics: Cost of study : 90 000 FF (1993)
6. Advantages: No information provided.
7. Constraints: Chlorides content in the water discharged
after the treatment plant. Respect of selenium discharge
standard.
8. Contacts:
Agence de l'eau Loire-Bretagne
M. R. BERTHEZENE
TEL: 33 38.51.73.73
M. AndrÆ BONNET
CERDEC FRANCE S.A.
2, avenue du PrÆsident Kennedy
87011 LIMOGES CEDEX - France
TEL: 33 55.30.44.44
FAX: 33 55.06.05.63
M. Maton
M. Chatenet
Office International de l'Eau
Direction de la Formation et des Etudes
rue Edouard Chamberland
87065 Limoges Cedex, France
TEL: 33 55114770
FAX: 33 55777115
9. Keywords: France, dye and enamel, recycling, heavy metal,
pickling, chlorine, ISIC 3521, cadmium, selenium
10. This case study was submitted to UNEP IE in 1994 by the
French Office International de l'Eau. It has not undergone
a formal technical review.