Raw Waste Loading Characteristics and Effluent
Quality in the Wet Process Hardboard
Manufacturing Industry
JOHN A. ROTH, Director
W. WESLEY ECKENFELDER, Executive Director
Center for Environmental Quality Management
Vanderbilt University
Nashville, Tennessee 37235
JAN A. OLESZKIEWICZ
Poland
INTRODUCTION
The hardboard manufacturing is one segment of the timber product processing
industry, which also includes veneer and plywood and wood preserving segments.
Hardboard or fibreboard is a generic term for a panel manufactured from inter-felted ligno-
cellulosic fibers consolidated under heat and pressure to a density of at least 0.5 g/cm3.
Other materials are added to improve or obtain such properties as stiffness, hardness,
finishing properties, resistance to abrasion and moisture, strength, durability, etc. (1).
There are two major categories in hardboard manufacturing based upon the manner in
which the fibers are carried and formed into the mat, and subsequently board. One is the wet
process where the water is used as the carrying medium. Another one is the dry process
where air serves the same function. This paper is concerned with the wet hardboard
processing industry. Of the 27 hardboard manufacturers in the United States, 10 are using
the wet process.
There are two major considerations in establishing effluent guidelines. These are
defining the raw waste load (RWL), i.e., amount of pollutant discharged per unit of
production per day, and determining the best practicable control technology (BPT).
The raw waste load can be affected by a number of factors, which may include the size
of the industrial plant, the age of the facility, variations in raw materials, variations in
process technology and equipment, and product specifications. Water reuse practice and
housekeeping will also have an effect on the RWL.
Insufficient data are available to determine if a relationship between the size of the
plant and the RWL exists. The raw waste load may increase with the length of time the chips
are in storage (3). Some breakdown occurs in the raw material with time, resulting in an
increased loss to the RWL. Age of wood is also one of the significant parameters affecting
the RWL. This age, long recognized as a variable in characterizing the pulp prepared for
further processing, has not been quantified from the standpoint of effects on the RWL.
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