Treatment

Presented at the Twentieth IT3 Conference, May 14-18, 2001, Philadelphia, USA

TREATMENT OF DIFFERENT WASTES BY SUPERCRITICAL WATER OXIDATION
Anders V. Gidner*, Lars B. Stenmark and Kim M. Carlsson
Chematur Engineering AB
Box 430, 691 27 Karlskoga, Sweden e-mail: [e-mail], Fax: [phone]
ABSTRACT
If left to conventional treatment processes, the destruction of toxic organic wastewaters and associated sludge volume reduction clearly becomes an overwhelming problem. Two options, incineration and supercritical water oxidation (SCWO), exist for the complete destruction of toxic wastewaters and organic sludges. Incineration has associated problems such as very high cost and public resentment; on the other hand SCWO has proved to be a very promising method for the treatment of many different wastewaters and sludges.
In early 1998 Chematur Engineering inaugurated its 250 kg/h SCWO demonstration facility and since then several successful treatability tests have been performed. Among these are tests with different complex wastes, from a SCWO process point of view. They have been performed in two different ways: 1.
Making the waste treatable in an “ordinary” SCWO unit, i.e. remove halogens and dissolved salts. 2.
Making the SCWO unit able to handle the difficulties in the waste, e.g. halogens.
Another waste, de-inking sludge, has been treated several times. The appealing results from these tests are that, besides the complete destruction of the organic material, the remaining paper filler has shown to be good enough for reuse. This exemplifies the general possibility to destroy the organic material in the waste by SCWO and leave a “clean” valuable inorganic material in the effluent, which could easily be recovered. The extremely clean inorganic material recovered ought to increase the interest in SCWO treatment. This type of waste may very well be the breakthrough of SCWO.
INTRODUCTION
Oxidation of organic wastes to carbon dioxide,