Waste Water Treatment Methods in the
Wood Preserving Industry
R. H. JONES, Vice President
W. R. FRANK, Environmental Engineer
Environmental Engineering, Inc.
Gainesville, Florida
C. I. HARDING, Senior Vice President
Reynolds, Smith and Hills
Architects-Engineers-Planners, Incorporated
Jacksonville, Florida
INTRODUCTION
The wood preserving industry, like most industries, is having to face the fact
that it can no longer discharge its wastewater untreated. This industry is unique in
that its purpose is to treat wood to prevent decomposition by plants, insects, bacteria
and fungus, therefore its wastewaters are toxic to biological waste treatment processes. Wastewater from the wood preserving industry contains not only concentrations of
various toxic chemicals but organic matter having a high BOD which must be decomposed.
The necessity of treating these toxic chemicals, along the removal of BOD,
produces an engineering challenge. Environmental Engineering, Inc. is actively engaged in the design of waste treatment systems for the wood preserving industry at
the present time. The following discussion of wastewater treatment in the wood
preserving industry results from laboratory analyses as well as from full scale plant
operation.
WOOD PRESERVING PROCESSES AND CHEMICALS
Wood products to be treated are usually conditioned by air seasoning, kiln
drying, steaming, or by heating in the preservative, either at atmospheric pressure or
under a vacuum. Following conditioning, the wood is then treated by a standard
process such as the Lowry or the Rueping process. Detailed information on wood
preserving processes may be found in many references (1,2,3,4).
Preservatives may be divided into four general categories: creosote and creosote
solution, oil borne preservatives, water borne preservatives and fire retardants. A list
of individual preservatives in each category is as follows:
1. Creosote and Creosote solutions
a. Creosote
b. Creosote - coal tar solutions
c. Creosote - petroleum solution
d. Creosote - pentachlorophenol solution
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