Pollution Control Activities At Georgia-Pacific

When solid wood wastes cannot be used in making pulp and, paper or sold for hog fuel, a properly designed and operated wigwam burner is an effective and economical alternative. Generally, if the moisture content of the waste is less than 60 percent, a burner with a tight shell, adjustable dampers on the overfire air ports, and adequate forced draft underfire air capacity will operate smoke-free. If the fuel moisture is greater than 60 percent, or if there are wide fluctuations in the feed rate to the burner, it is necessary to use a damper in the top of the burner to control the burning rate and to use forced draft overfire air fans with hot air recirculation in the burner. Use of an auxiliary fuel, such as oil or gas, may also be necessary in this case. Water used for cooling narrow kerf saws and for log deck sprinkling is screened, settled, and recirculated. Hydraulic barker water requires more extensive treatment because it has a high concentration of very fine suspended solids and leached organics from the bark which create a highly visible plume when discharged. Removal of the objectionable material requires a clarifier and addition of chemicals to coagulate the particles. The water is then reused in the hydraulic barker. Air pollution from plywood mills comes from two source’s, sander dust cyclone emissions and veneer dryers. Regulations now being adopted for cyclones cannot be met with the conventional cyclone installation. The only equipment that can comply with the regulations is a bag filter, although a tube-type filter and a high efficiency cyclone have been introduced which are claimed to be successful. Veneer dryer emissions are the second air pollution source from plywood mills. Preliminary studies indicate that these emissions are principally high molecular weight hydrocarbons which condense just above 100?F. If this finding is confirmed, control by condensation may be possible. Plywood glue waste water disposal is the main water pollution problem associated with plywood mills. The first step to solving this problem is to cut water usage to a minimum and to segregate it from uncontaminated water. Waste water containing phenol glue can be recycled by screening and settling. Wash water from urea base glues and protein base glues can also be reused; however, care must be taken to use the water before biological degradation of the glue occurs. Separate recycle systems for urea and protein glues are necessary, since the two glue waters gel if mixed. Fumes originating from the tempering oven of a dry process hardboard plant are an air pollution problem. The fumes were shown to be acrolein. The problem was solved by installing an incinerator on the oven exhaust vents.

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