ENVIRONMENTAL LOADS FROM WATER-SPRINKLED SOFTWOOD TIMBER: 2. INFLUENCE OF TREE SPECIES AND WATER CHARACTERISTICS ON WASTEWATER DISCHARGES

摘要

The concentration patterns of a number of compounds in the inlet water and wastewater from sprinkling of timber from Scotch pine and Norway spruce have been studied. The timber was separated with respect to species and sprinkled with water from a eutrophic or an oligotrophic receiving water for 18 weeks. Organic and inorganic compounds including dissolved organic carbon (DOC), distillable phenols, resin acids, bacterial phospholipid fatty acids, organic and inorganic phosphorus, nitrogen and sulphur, and a number of metal ions were monitored in the inlet water and wastewater. The toxicity of the wastewater was estimated during the first 2 weeks using a Microtox~® test and appeared to decline in parallel with DOC. Most compounds showed both an environmental net load and an absorption by the timber, the loads being smaller and the absorption larger when using eutrophic water. At both sites the loads were generally largest during the first 2 weeks and larger in magnitude at the oligotrophic site and in the spruce wastewater. The initial growth of the bacterial biomass in the pile system was slower at the oligotrophic site, and the results indicated that a rapid growth of the bacterial biomass reduces the initial environmental loads and that this process is associated with the nutrient status of the receiving water.