29    SUPPLEMENTED KRAFT CONDENSATE TREATMENT IN
HIGH RATE ANAEROBIC PROCESSES
H. M. Poggi, Graduate Student
Department of Civil Engineering
University of Manitoba
Winnipeg, Manitoba
Canada R3T 2N2
R. Hernandez, Research Associate
N. Rinderknecht, Research Associate
Biotechnology Department
Center for Higher Studies and Research, Anvestav
Mexico City, Mexico
J. F. Calzada, Head
Industrial Research Division
Central American Institute for Industrial Research
Guatemala City, Guatemala
INTRODUCTION
In Mexico, four big industrial activities account for nearly 90% of the industrial wastewater
discharges, as shown in Table I. They are the sugar industry, the pulp and paper manufacture in
second place, the steel industry and the oil production and refining.'
The Mexican pulp and paper industry generates about 12% of the volume of the industrial wastewaters, and it is known that many of the substances contained in these wastewaters are toxic or at least
refractory to biological degradation.2,3
Almost 75% of the Mexican pulp is manufactured using the Kraft process with pine wood as
feedstock. The Kraft process involves the digestion of wood chips with an alkaline-sulfidized liquor,
and the subsequent bleaching of the raw pulp with chlorine and other oxidant compounds. The spent
liquor is further concentrated by evaporation in multi-effect evaporator trains, and burned for
chemicals recovery and reuse. This concentration stage is the source of the so named Kraft condensate
(KC).
At present, the Mexican pulp and paper industry is facing strong pressures dealing with new
discharge permits and limits, according to new regulations issued by the Mexican Ministry of Environment and Urban Development. In this context, a research project was started, aimed at assessing the
Table I.    Industrial Wastewater Discharges in Mexico
Discharges
Industry M rnVyear
Sugar
620
Pulp and Paper
100
Steel
38
Oil
31
Chemical
21
Textile
21
Tannery
12
Food
11
Coffee
5
44th Purdue Industrial Waste Conference Proceedings, © 1990 Lewis Publishers, Inc., Chelsea, Michigan 48118.
Printed in U.S.A.
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