Papermaking industrial wastewater refers to the wastewater generated in the pulp and paper production process. The characteristics of the paper industry wastewater are large wastewater discharge, high BOD, and many fiber suspensions in the wastewater, and the industrial wastewater containing divalent sulfur and colored paper refers to the wastewater generated in the pulp and paper production process.

Production in the paper industry is divided into two main process stages, namely pulping and papermaking. Pulp making is to separate the fibers from plant raw materials to make pulp, which is then bleached; paper making is to dilute, shape, press, and dry the pulp to make paper. Both processes consume a lot of water, most of which is discharged as wastewater.

The characteristics of papermaking industrial wastewater are large wastewater discharge, high BOD, many fiber suspensions in the wastewater, and it contains divalent sulfur and color, and has a bad odor of mercaptans.

The composition of pulp 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 type of product and the type of raw materials. Suspended substances in the wastewater of the paper industry mainly come from bark, grass clippings, sand and sand, ash, slag, fibers and fillers lost in each process of pulp and paper making in the preparation section; BOD in wastewater mainly comes from pulping Cooking process, such as sugars, alcohols, organic acids, etc. generated by cellulose decomposition, in chemical pulp, the amount of BOD5 in cooking waste liquid accounts for more than 80%; COD and coloring substances in wastewater mainly come from the pulping cooking process The lignin and its derivatives; the toxic substances in wastewater are mainly crude sulfate soap in cooking waste liquid, organic chloride in bleaching wastewater (such as dichlorophenol, chlorocatechol, etc.), as well as trace amounts Mercury, phenol, etc., but these toxic substances are usually in very small amounts. Among them, the toxicity and “three effects” of organic chloride in bleaching wastewater have attracted more and more attention in developed countries.

In China, due to the large proportion of grass fiber raw materials (about 60%), the scale of the enterprise is small, the production technology and equipment are backward, and the raw materials, energy, and water consumption are large, which makes the pollution of the pulp and paper industry in China particularly serious. It is estimated in 1985 , China ’s paper industry has an annual displacement of 37 billion cubic meters, second only to the chemical industry and the steel industry, ranking third, accounting for about 1/10 of the total industrial wastewater discharge; the BOD5 load discharged is 210 kg per ton of product, and the annual discharge BOD5 is 1.73 million tons, accounting for 1/4 of the country's total BOD5 emissions.

Pulp and paper wastewater can be roughly divided into: pulp cooking liquor, washing wastewater, bleaching wastewater and paper machine white water. Alkaline pulp cooking waste liquid, also known as "black liquor", is the main source of pollution in pulp mills.

Physical Chemistry Method

In the advanced treatment of papermaking wastewater? Physical and chemical method has the advantages of fast treatment and good treatment effect. The commonly used methods include advanced oxidation method, flocculation precipitation method, membrane separation method adsorption method, etc.

Advanced Oxidation Process Advanced Oxidation Processes (AOPs for short), also known as deep oxidation technology, is a new technology developed in the 1980s for the treatment of refractory organic pollutants. Under the action of oxidant, electricity, sound, light irradiation, catalyst, etc., it produces extremely strong oxidizing ability (its potential is 2.80V? Second only to fluorine 2.87V) ˙OH? Then through the addition between OH and organic compounds, The functions of substitution, electron transfer, bond breaking, ring opening, etc. make the refractory macromolecular organic matter in the wastewater oxidatively degrade into low-toxic or non-toxic small molecular substances, and even directly decompose into CO: and H: O to achieve harmlessness the goal of. The technology has the advantages of fast reaction speed, high processing efficiency, complete destruction of toxic pollutants, no secondary pollution, wide application range, easy operation, etc., and is widely used in toxic and difficult to degrade industrial wastewater such as pharmaceuticals, fine chemicals, printing and dyeing, etc. In the treatment of organic wastewater, it has gradually become a hotspot in the research of refractory wastewater treatment. According to the way of generating free radicals and the reaction conditions, it can be divided into Fenton oxidation method, supercritical water oxidation method, photocatalytic oxidation method, ultrasonic oxidation method, electrocatalytic oxidation method, ozone oxidation method and wet oxidation method, etc. .

Flocculation and sedimentation method Flocculation and sedimentation method is a polymerization product formed by flocculant, through a series of actions, to remove suspended, colloidal macromolecular mass pollutants in water. For the three-stage treatment of pulp and paper wastewater, this method has been widely used. Under optimal operating conditions, flocculation-electric flotation is used to continuously treat papermaking wastewater. The CODcr of wastewater can be reduced from 1416mg / L to 48.9mg / L.

Membrane separation method Membrane separation method uses a special semi-permeable membrane to separate the solute and the solvent, so that a certain solute in one side of the solution penetrates through the membrane or solvent, so as to achieve the purpose of separating the solvent. Guan Yuntao et al. Used a traditional two-phase anaerobic process (BS) combined with membrane separation technology (MBS) to treat papermaking black liquor configuration wastewater. The results show that the system COD removal rate can reach 73.1, higher than the BS system (48.6 %), And is superior to the BS system in terms of anaerobic sludge activity and operational stability; when the COD load is 6kg˙ (m3˙d) -1, the MBS acidification rate is 20.1%, and the acidification level is 7.5%, slightly better than BS system (7.0% and 5.0% respectively).

Seat Cushion

This seat cushion is very popular and widely used in home, coffee shop and restaurant, you could match our Dining Chair and Living Room Chair together.

We use environmental material and provide the perfect items.

This seat chair is available in a selection of colours .


We also have many Home Accessories to decorate your home.


If you need more information, just feel free to contact me, I will send you more details pictures and information.

Comfort Office Chair Seat Cushion,Chair Seat Cushion,Comfort Chair Pads,Living Room Chair Seat Cushion

Ningbo Realever Enterprise Limited , https://www.realeverfurnishing.com