INTERNATIONAL CLEANER PRODUCTION INFORMATION CLEARINGHOUSE

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.