Paper mill sludge treatment is an important part of the paper industry, with the enhancement of environmental protection awareness, how to effectively deal with the sludge produced by paper mills has become the focus of the industry. This paper will introduce the methods and steps of sludge treatment in paper mills, in order to provide reference for solving the problem of sludge pollution in paper mills.
First, the characteristics and characteristics of sludge.
Paper mill sludge is mainly used in the wastewater generated in the pulp and paper making process, and the solid waste produced by these wastewater after treatment is sludge. Paper mill sludge usually contains a large amount of lignin, cellulose degradation products, fillers, rubber and other substances, and may also contain heavy metals, toxic and harmful substances, etc. Therefore, paper mill sludge has the characteristics of high moisture content, high organic matter content, and easy to spoil.
2. Objectives and principles of sludge treatment.
The goal of sludge treatment in paper mills is to reduce, stabilize, harmless, and recycle sludge. In order to achieve these goals, the following principles should be followed in the treatment of sludge in paper mills:
1.Reduction: Reduce the difficulty and cost of final disposal by reducing the moisture content and volume of sludge;
2.Stabilization: decompose the organic matter in the sludge to reduce the harm to the environment;
3.Harmless: remove or reduce toxic and harmful substances in sludge to meet discharge standards;
4.Recycling: Convert sludge into valuable resources, such as fertilizer, building materials, etc.
3. Sludge treatment method.
1.Natural dehydration.
Natural dewatering is a method of placing sludge in a natural environment to reduce the moisture content of sludge through evaporation and osmosis. This method is suitable for sludge with low water content, but pretreatment is required for sludge with high water content.
2.Mechanical dehydration.
Mechanical dewatering is a method of using mechanical equipment to dewater sludge, and commonly used mechanical dewatering equipment includes filter presses, centrifuges, etc. Mechanical dewatering can quickly and effectively reduce the water content of sludge, but it requires a lot of energy and cost.
3.Biological dehydration.
Biological dewatering is a method that uses microorganisms to decompose organic matter in sludge, release water and generate biological gas. Biological dewatering reduces the water content and organic content of sludge, while the resulting biogas can also be used as an energy source.
4.Chemically stable.
Chemical stabilization is the use of chemical agents to modify sludge to make its properties stable and reduce the harm to the environment. Commonly used chemicals are lime, acid, alkali, etc. Chemical stabilization can effectively reduce toxic and harmful substances in sludge, but the dosage and cost of chemicals need to be reasonably controlled.
5.Heat treatment.
Heat treatment is a method of treating sludge at high temperatures to evaporate the water in it and reduce the organic content. Heat treatment can effectively reduce the volume and weight of sludge, but it requires a lot of energy and cost.
6.Land use.
Land use is the method of using treated sludge for land improvement, landscaping, etc. Land use can make full use of the organic matter and nutrients in sludge while reducing pollution and emissions to the environment. However, it should be noted that land use needs to strictly control the content of toxic and harmful substances in sludge to avoid harm to the environment and human health.
IV. Conclusions. Sludge treatment in paper mills is one of the important links to achieve sustainable development of the paper industry. By selecting appropriate treatment methods and equipment, the reduction, stabilization, harmlessness and resource utilization of paper mill sludge can be effectively realized. In the future, with the continuous progress and application of environmental protection technology, paper mill sludge treatment will be more efficient, environmentally friendly and economical. At the same time, the first and all sectors of society should also strengthen the supervision and support for the sludge treatment of paper mills to promote the green development of the paper industry.