造纸工业生产分为两个主要工艺阶段，即制浆和抄纸。制浆是把植物原料中的纤维分离出来，制成浆料，再经漂白；抄纸则是把浆料稀释、成型、压榨、烘干制成纸张。这两项工艺都要耗用大量的水，其中大部分作为废水排出。

The production of paper industry is divided into two main process stages, that is, pulping and papermaking. Pulping is the separation of fiber from plant material to make slurry and then bleach. Paper is used to dilute, form, press and dry pulp to make paper. Both of these two processes use a large amount of water, most of which are discharged as waste water.

造纸工业废水的特点是废水排放量大，BOD高，废水中纤维悬浮物多，而且含二价硫和带色，并有硫醇类恶臭气味。

The wastewater of papermaking industry is characterized by large amount of wastewater discharge, high BOD, high fiber suspended matter in wastewater, and containing two valence sulfur and color, and thiols odor.

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。

The composition of pulping and papermaking wastewater is very complex, and its composition depends not only on the method of pulp, but also on various factors such as the variety and the type of raw material. Papermaking wastewater by suspended substances are mainly derived from the preparing process of bark, grass clippings, sediment and water discharge with ashes, slag, pulping and papermaking process, the loss of fiber filler; BOD in wastewater mainly comes from pulping processes, such as cellulose decomposition of sugars, alcohols, organic acids, in chemical pulp in the waste liquor of BOD5 accounted for more than 80%; lignin and its derivatives in wastewater COD and coloring materials are mainly derived from the pulp cooking process; toxic substances in wastewater are the main cooking waste in crude sulfate soap, organic chloride bleaching waste water (such as phenol, catechol and two chlorine chloride), and trace mercury, phenol and other toxic substances, but these usually content is little, the organic chloride in bleaching wastewater on the toxicity and the role of the "three letter", in the developed countries More and more attention has been paid.