Paper Making Industrial Wastewater Introduction

Pulp and paper production generally consists of pulping, pulp washing, bleaching and paper making processes. Pulping in the paper industry includes alkaline pulping, chemical-mechanical pulping and mechanical pulping. According to different pulping methods, different raw materials, different pulping yields, different types of paper making, and whether chemicals are recycled, the occurrence and discharge of pollutants are very different, but basically they contain a large number of suspended solids, BOD, COD and some toxic substances, which are still treated by a combination of physicochemical and biological methods.

Papermaking wastewater mainly comes from pulping and papermaking processes in the production of paper industry. Including pulping and cooking waste water, washing waste water, bleaching waste water and paper machine white water. The composition of papermaking wastewater is complex, and its biodegradability is poor. It belongs to industrial wastewater that is difficult to treat.

Source of Papermaking Wastewater

• The waste liquid from cooking wood pulp (or straw pulp) is also called black liquor.
• The waste water discharged from the beater and refiner is called beating waste water.
• Paper machine wastewater, which can be directly used, is called white water.

 Alkaline pulp cooking waste liquor, also known as "black liquor", is the main pollution source of pulp mills.The waste water discharged during pulp washing is dark brown, called black water. The concentration of pollutants in the black water is very high, with BOD as high as 5-40g/L, containing a large amount of fiber, inorganic salt and pigment. The waste water from the bleaching process also contains a lot of acid and alkali substances. The waste water discharged from the paper machine is called white water, which contains a large number of fibers and fillers and adhesives added in the production process.

Characteristics of Papermaking Wastewater

The composition of papermaking wastewater is complex and its biodegradability is poor. It belongs to industrial wastewater that is difficult to be treated. The main pollutants contained in it are as follows:

Suspended solids: including settleable suspended solids and non-sedifiable suspended solids, mainly fibers and fiber fines (i.e. broken fiber fragments and miscellaneous cells).

Biodegradable organics: including hemicellulose, methanol, acetic acid, formic acid, sugar, etc. with low molecular weight.

Refractory organics: mainly from lignin and macromolecular carbohydrates contained in fiber raw materials.

Toxic substances: rosin acid and unsaturated fatty acid contained in black liquor.

Acid-base poison: pH value of alkaline pulping wastewater is 9-10, and that of acid pulping wastewater is 1.2-2.0.

Chromaticity: residual lignin contained in pulping wastewater is highly colored.

Paper Making Industrial Wastewater Treatment

The treatment of paper industry wastewater should focus on improving the rate of circulating water use, reducing water consumption and wastewater discharge, and actively explore various reliable, economic and effective treatment methods that can make full use of useful resources in wastewater.

• The flotation method can recover the fibrous solid substances in white water with a recovery rate of 95%, and the clarified water can be reused.
• The combustion method can recover sodium hydroxide, sodium sulfide, sodium sulfate and other sodium salts combined with organic substances in black water.
• Neutralization method regulates the pH value of wastewater.
• The suspended solids in wastewater can be removed by coagulation sedimentation or flotation.
• Chemical precipitation can decolorize.
• Biological treatment can remove BOD, which is more effective for kraft paper wastewater.
• The wet oxidation process is successful in treating sulfite pulp wastewater. 

Consider Electrocoagulation Dissolved Air Flotation (EC+DAF) System

Our industrial eco fast efficient waste water treatment systems plant adopts electrocoagulation dissolved air flotation (EC+DAF) system, 

Electrocoagulation dissolved air flotation (EC+DAF) is a wastewater treatment system that combines two processes - electrocoagulation and dissolved air flotation - to remove contaminants from wastewater. Here are some advantages of an EC+DAF system:

1. High efficiency: The EC+DAF process can remove suspended solids, turbidity, oils and grease, heavy metals, and other contaminants from wastewater with a high degree of efficiency.

2. Reduced chemical usage: The process uses electrical charges and air flotation to remove contaminants from wastewater, thereby reducing the need for chemical usage.

3. Compact design: EC+DAF systems have a small footprint, making them ideal for small and medium-sized treatment plants where space is limited.

4. Easy maintenance: The system requires minimal maintenance due to its simple design, which reduces operating costs.

5. Environmentally friendly: The EC+DAF process does not generate any hazardous waste or by-products, making it an environmentally friendly option.

6. Versatile: EC+DAF systems can be used for the treatment of various types of wastewater, including industrial wastewater, municipal wastewater, and agricultural wastewater.

7. Low energy consumption: The process uses low electric power and air, making it cost-effective in terms of energy usage.

In short an EC+DAF system is an efficient, cost-effective, and environmentally friendly option for treating wastewater. If you are planning to choose a more efficient way for wastewater treatment, this industrial eco fast efficient waste water treatment systems plant is your best choice.

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