Biodegradation of chlorophenolic compounds in wastes from wood-processing industry

In Finland million metric tons of pulp were produced in 1982, Of which 3.0 million tons were bleached (3), involving the use of 0.18 million metric tons of chlorine. Approximately of this chlorine reacts with organic compounds and is released from the mill in the effluent water (8, 47; M. S. Salkinoja-Salonen, R. Hakulinen, R, Valo, and J. Apajalahti, Water Sci. Technol., in press). The annual pollution load of chloroor-ganic compounds from the Finnish chemical wood processing industry can be estimated from production figures by using data for the pollution load of bleach plant emuents (27, 32, 36, 47), which is 100,000 tons of chlorolignin, 1,000 tons of chlorinated phenolic compounds, 1,000 to 2,000 tons of chloroform, and an as yet unknown amount of chlorinated resin acids, steroids, and Other wood extractives. During the manufacture Of timber and lumber, wood-preserving chemicals are used, chlorophenols being the
most widely applied in Finland. Their estimated usage is 1,500 tons per year in Finland.
Chloroorganic chemicals are known for their biological recalcitranée (16), and as a result their biodegradation has been widely studied (for recent reviews, see, for example, 31, 35). However, the chemicals that have been investigated are mostly pesticides or other industrial products. In 1978, when we started to study the environmental fate of chloroorganic chemicals that arise from the wood-processing industry, this field was little studied. In this paper we describe some of our recent results on the environmental behavior of chloroorganic compounds from the wood-processing industry and the possibilities of using biological treatment for reducing the pollution load from this branch of industry.