制浆造纸废水的成分很复杂

制浆造纸废水的成分很复杂，其组分不仅取决于纸浆的方法，也取决于所产品种和原料种类等多种因素。造纸工业废水中的悬浮物质主要来自备料工段的树皮、草屑、泥沙以及随水排放的炉灰、矿渣、制浆造纸各工序流失的纤维、填料等；废水中BOD主要来源于制浆蒸煮工序，如纤维素分解生成的糖类、醇类、有机酸等，在化学浆中，蒸煮废液的BOD5发生量占80%以上；废水中的COD和着色物质主要来源于制浆蒸煮工序的木素及其衍生物；废水中的有毒物质主要有蒸煮废液中的粗硫酸盐皂、漂白废水中的有机氯化物（如二氯苯酚、氯邻苯二酚等），还有微量的汞、酚等，但这些有毒物通常含量甚微，其中关于漂白废水中的有机氯化物的毒性和“三致”作用，在发达国家中已引起越来越大的关注。在我国，由于草类纤维原料比重大（约占60%），企业规模小，生产工艺和设备落后，原材料、能源、耗水量大，使我国的制浆造纸工业的污染格外严重，1985年估算，我国造纸工业年排水量为370亿立方米，仅次于化学工业和钢铁工业，居第三位，约占工业废水总排放量的1/10；排放的BOD5负荷每吨产品为210kg，年排放BOD5为173万t，占全国BOD5总排放量的1/4。 The composition of pulp and paper waste water is complex, its composition not only depend on the method of pulp, but also depend on the variety of factors such as the product and the kind of raw material. Suspended material in papermaking wastewater mainly comes from the bark of preparation section, clippings, sediment, and emissions of soot from a furnace with the water, slag, pulp and paper loss in each process of fiber, packing, etc.; BOD in the wastewater from pulp cooking process, such as the production of cellulose decomposition of sugars, alcohols, organic acids, etc., in chemical pulp cooking effluent BOD5 number accounts for more than 80%; The COD and colouring substances in wastewater are derived from the lignin and its derivatives of the cooking process. The toxic substances in waste water mainly include cooking waste liquid of the organic chlorides in crude sulfate soap, bleaching wastewater (such as dichlorophenol and chlorine catechol, etc.), and trace amounts of mercury, phenol, etc., but usually these toxins content with little, of bleaching effluent of the toxicity of organic chloride and "three to" effect, in the developed countries has aroused more and more attention. Fiber raw material in our country, because the grass than big (about 60%), small enterprise scale, production technology and equipment, raw materials, energy and water consumption is big, make China's pulp and paper industry pollution is particularly serious, estimated in 1985, China's paper industry in displacement of 37 billion cubic meters, second only to the chemical industry and steel industry, in the third place, accounts for about 1/10 of the total emissions of industrial waste water. The emission's BOD5 load is 210kg per ton, and the annual emission of BOD5 is 1.73 million t, which accounts for about a quarter of the national total of BOD5.