Effluent compliance through pigging

Champion International Corporation's mill at Sheldon, Texas produces an average of 1,275 tons of newsprint per day. Effluent flow of 16. 0-18. 0 MG/D from three paper machines (kraft, TMP and groundwood pulping) is treated in an activated sludge treatment plant. The treated effluent is pumped to the Houston Ship Channel with a 700 horsepower pump through a 13 mile long, 42 inches diameter reinforced concrete pipeline. Effluent compliance was difficult in times of high flows. In June of 1986, the pipeline was cleaned by sending a number of poly pigs through the line. This paper deals with the details of inspecting the pipeline and the rationale of making a decision to pig clean the line