How to realize the recycling of paper sludge in paper mills

The paper mill sludge has always caused headaches for the Ministry of Environmental Protection and the paper mills. The black sludge is only contaminated and poses a considerable threat to the environment. Today, the sludge disposal environmental protection enterprise comprehensively analyzes how the paper sludge dewatering equipment can realize the recycling of paper sludge.

Three characteristics of paper sludge

High moisture content. The original sludge produced by the paper mill has a moisture content of more than 99%. After concentration, the water content is still above 95% and has fluidity.

The fiber content is large. The paper sludge contains a large amount of fiber. Compared with municipal sludge, the organic matter content is low, and the deep dewatering of the sludge is difficult.

The paper mill produces a large amount of mud. Influent SS is 2100～4400mg/L, CODcr is 1700～4800mg/L; effluent SS is 15～40mg/L, CODcr is 70～100mg/L.

Paper sludge resource disposal process

Paper sludge quenching and tempering

After the paper sludge is concentrated, it is modified by adding an appropriate amount of quenching and tempering agent to reduce the hydrophilicity and facilitate mechanical drying. Zhengzhou Dingsheng does not need to add lime when tempering the paper sludge. It only needs to add 1%-2% of the common tempering agent (sludge with 80% water content) to the mud.

Mechanical drying of paper sludge

The quenched and tempered paper sludge can be pumped into the sludge deep dewatering equipment by the sludge feed pump, such as the Dingsheng ultra-high pressure sludge dryer. The sludge is first subjected to preliminary dewatering under the pressure of the feed pump. When the sludge deep dewatering equipment is filled with sludge, the sludge feed pump is closed, and the sludge dryer starts to smear with a pressure of 6-8 MPa. When the mud is pressed, the filtrate gradually flows out from the sludge drying machine filter tube, and the mud cake is automatically detached from the sludge dryer under the action of the pneumatic unloading device, and is transported to the designated position by the conveyor belt. Since then, the paper pulp with high water content has formed a dry hard mud cake to achieve deep dewatering and reduction of sludge.

Wastewater treatment of paper sludge

After deep dewatering, the paper sludge can be sent to power plants for incineration power generation and heating. It can be used as building materials for bricks, cement, etc., and can also be used as a roadbed. According to local conditions, the paper mill cooperates with building materials units or power plants to realize the recycling of paper sludge.