In the paper industry, the main materials used are wood, reeds, straw, etc., which are non cellulose black liquids discharged after processing.

The wastewater in the papermaking industry is a relatively difficult type of industrial wastewater treatment. The reason is that papermaking wastewater contains many pollutants, suspended solids, colors, and harmful substances, as well as some difficult to degrade cellulose, organic matter, and toxic substances. Therefore, the treatment of this wastewater is more difficult and toxic.

What are the methods for treating industrial wastewater in the papermaking industry, and how should it be treated the best way?

1. Physical Law:

Physical methods are generally divided into precipitation method, filtration method, centrifugal separation method, etc., mainly used to remove solid suspended solids in industrial wastewater;

Precipitation method: By utilizing the weight difference between some particles in wastewater and water, under the action of gravity, heavier pollutants will settle at the bottom and be separated from the wastewater;

Filtration method: Separation of suspended solids with relatively large diameters is achieved through filtration equipment such as filters, vacuum filters, and filter presses, resulting in the purification of wastewater.

2. Chemical method:

Neutralization method: Based on the acidity or alkalinity of the wastewater, add an opposite acidic or alkaline substance to neutralize the pH value of the wastewater, allowing it to suspend and precipitate, and then remove the sediment.

Oxidation method: Oxidation method is to add oxidants or reducing agents to wastewater, causing pollutants in the wastewater to undergo oxidation or reduction reactions, converting organic pollutants into harmless substances.

Common reducing agents include ferrous sulfate, sodium bisulfite, etc; Oxidants include bleach, ozone, chlorine gas, etc;