Solution for Woven Paper Wastewater Treatment
The global corrugated cardboard market is expected to reach approximately $153.6 billion in 2024 and is projected to grow to $277.75 billion by 2033, with a compound annual growth rate of approximately 4.9% - 5.0% during this period. The core driving force of the market comes from population growth,consumption upgrading,and enhanced hygiene awareness.
Corrugated cardboard, as the core packaging material in fields such as e-commerce logistics, food and beverage, and home appliances, its market demand is highly correlated with global economic activities, online consumption trends, and environmental protection policies. In recent years, driven by the explosive growth of e-commerce and the rising demand for sustainable packaging, corrugated cardboard, due to its recyclability, lightweight nature, and strong protection, has become one of the fastest-growing packaging categories.
I. Overview of Customers for Corrugated Paper Wastewater Treatment
The corrugated paper industry is one of the traditional heavily polluting industries. The wastewater generated during its production has had a significant impact on the environment. With increasingly strict environmental regulations and the enhanced public awareness of environmental protection, more and more corrugated paper enterprises are beginning to attach importance to wastewater treatment and seeking professional wastewater treatment solutions. These customers range from small and medium-sized paper mills to large pulp and paper groups. They hope to achieve compliant discharge or resource utilization of wastewater through effective wastewater treatment technologies, thereby reducing the impact on the environment and enhancing their corporate social responsibility and competitiveness.
II. Wastewater Treatment of Corrugated Paper Corrugated Paper Wastewater Source
The wastewater of corrugated paper mainly originates from various production processes such as pulping, bleaching, papermaking, and log preparation. Its composition is complex and the pollution load is high. Specifically, the wastewater of corrugated paper mainly includes the following categories:
1. Wastewater from the rinsing process in corrugated paper production
During the production of corrugated paper, processes such as paper heating, forming the shape, applying glue, cutting the paper board, and printing will generate wastewater. Especially in the feeding and returning system of the corrugating machine, due to the viscosity of the starch adhesive and its susceptibility to bacterial, mold, scale, dust contamination in a high-temperature and high-humidity environment, a large amount of wastewater containing starch adhesive will be produced during the cleaning process. The starch adhesive in these wastewater enters the water, causing the COD (Chemical Oxygen Demand) and BOD (Biochemical Oxygen Demand) concentrations in the wastewater to be relatively high.
2. Water-based ink printing wastewater from flexible plates
In the printing process of corrugated paper, flexible plates are used. This ink is mainly composed of water-soluble resins, organic pigments, solvents, and related additives through compounding and grinding. During the rinsing process of the printing equipment, these pigments will enter the environment with the wastewater, resulting in high color intensity and difficulty in removal.
3. Wastewater from the waste paper pulping process
In the production of high-strength corrugated paper, waste paper pulping is an important process. The waste paper is crushed, high-concentration sand removal, pulp selection, tail pulp fiber separation, light and heavy quality combination low-concentration sand removal, pulp concentration, and pulping are carried out. These wastewater contain a large amount of organic substances such as lignin, cellulose, and hemicellulose, which are important sources of pollution in the wastewater.
4. Wastewater from the papermaking process
In the papermaking process, the pulp from the paper mill is transported to the pulp storage tank and various additives are added. The formulated pulp is sent to the low-pulse filling pump for filling and then to the low-pulse filling pump for filling through a pressure seam screen and enters the fabricator. The WK hydraulic pulp box evenly distributes the pulp from the fabricator and sends it to the single-length net forming machine. During this process, the white water generated by the papermaking section is directly recycled for the pulping section, and the excess white water and sludge filter wastewater are combined and sent to the plant's wastewater treatment station for treatment.
5. Wastewater from log preparation
During the log preparation process, the mechanized peeling of logs is mostly carried out in the peeling drum. There are two types: dry method and wet method. The wastewater from the peeling section of the log preparation workshop contains a certain amount of wood extractive components, which exist in the form of dissolved colloidal substances and are important sources of toxicity in the wastewater. Although the wet peeling method can obtain better quality logs, it generates a certain amount of wastewater and pollutants.
6. Wastewater from non-wood raw material preparation
In China, non-wood raw materials widely used in the pulp and paper industry include wheat straw, rice straw, sugarcane bagasse, bamboo, and reed. Taking the preparation of grass raw materials as an example, the preparation process of grass raw materials mostly adopts the dry method. To prevent a large amount of dust and grass debris from flying and causing air pollution, most factories add spray devices for dust reduction in the dust collection and dust removal equipment. The result is that the pollution to the atmosphere is reduced, but a large amount of suspended matter is transferred to the water, that is, from air pollution to water pollution. At the same time, grass debris and some water-soluble substances in the raw materials enter the preparation wastewater, increasing the BOD5 and CODcr in the wastewater.
III. Wastewater Treatment Process for Corrugated Paper
In response to the characteristics of corrugated paper wastewater, we have designed a scientific and efficient wastewater treatment process, which mainly consists of the following steps:
1. Pre-treatment stage: The core function is to remove large particles of impurities, such as adhesives and impurities in waste paper, to ensure the normal operation of the production line. This step is crucial because different types of paper require different treatment methods.
2. Equalization tank: It is used to regulate the volume and quality of wastewater, enabling the subsequent treatment process to operate stably. The design of the equalization tank should take into account the requirements of the incoming water quality and the outgoing water quality to ensure the advancement and reliability of the treatment process.
3. Primary sedimentation tank: It achieves effective separation of sludge from water through sedimentation, removing suspended solids and some organic substances from the wastewater.
4. Air flotation tank: It is used to remove floating oil and suspended solids, improving the treatment effect of the wastewater.
5. Anaerobic digestion tank: Through microbial action, organic matter is degraded and converted into biogas, with a high organic load, which can be recycled as energy.
6. Contact oxidation tank: It achieves organic matter degradation through microbial action, with a fast biofilm formation and short start-up time, resulting in significant environmental benefits.
7. Secondary sedimentation tank: It realizes the separation of aerobic effluent from water, with the clear water being reusable or discharged, and can also enter the subsequent deep treatment process.
8. Sludge storage tank and sludge thickening tank: They are used to store and concentrate the sludge generated during the treatment process, facilitating subsequent sludge dewatering and disposal.
9. Sludge dewatering machine: It performs dewatering treatment on the concentrated sludge, reducing the volume of sludge, and facilitating transportation and disposal.
Industrial Wastewater → Screen Filter → Equalization Tank → IC Anaerobic Reactor → Aerobic Biochemical Tank → Secondary Sedimentation Tank → Advanced Treatment → Discharge up to Standard
IV. Specific Case Studies of Wastewater Treatment for Corrugated Paper
Shandong Zibo Wan Song Paper Industry Co., Ltd. Aerobic Aeration System for Sewage Ponds
I. Company Introduction:
The main product of Shandong Zibo Wan Song Paper Industry Co., Ltd. is Grade B medium-strength corrugated paperboard base paper, and it will provide related after-sales services. The company's product sales channels mainly include wholesalers, packaging factories, and carton factories in various cities across the country. The sales network covers the entire province, Zhejiang, Hebei, Tianjin and other provinces and cities. The company has one sewage treatment plant, which is responsible for treating the papermaking wastewater of the company. The treated wastewater can be applied to the paper machine to form water recycling.
II. Aerobic Aeration Retrofit
The papermaking wastewater contains a large amount of fibers, paper pulp and other suspended impurities. Traditional fixed aeration devices are prone to clogging, resulting in oxygen supply interruption. The "One-to-Four" system can lift the aeration device to directly clean the surface and does not require production shutdown for emptying, fundamentally solving the problem of impurity clogging.
During paper production, the water inflow and COD concentration often fluctuate with production capacity adjustment, which will lead to a sudden increase in the organic load of the aerobic tank and an increase in microbial oxygen consumption. This aeration device can independently control each group of aeration units and flexibly adjust the supply of air volume to match the real-time oxygen consumption demand.
III. Core Effects Achieved After Installation
1. Improve the efficiency of wastewater treatment: The tiny bubbles produced by the aeration device significantly increase the contact area between gas and liquid, and the oxygen utilization rate is significantly improved. It can quickly maintain the dissolved oxygen in the aerobic tank at the optimal range of 2-4mg/L, ensuring that microorganisms can efficiently degrade pollutants such as COD and BOD, and the effluent quality is stable and superior to the "Papermaking and Pulp Industry Water Pollutants Discharge Standard" (GB 3544-2018).
2. Reduce operating and maintenance costs: The high oxygen transfer efficiency can reduce the energy consumption of the fan; maintenance does not require emptying the water tank or re-cultivating the bacteria, and the single group maintenance cost is reduced by more than 60%, and the annual operation and maintenance cost is saved by 30%-40%.
3. Ensure continuous and stable operation of the system: Avoid processing interruptions caused by aeration device blockage or maintenance shutdown, reduce the risk of sludge activity decline and effluent exceeding standards, and at the same time, the equipment uses anti-corrosion materials, with a service life of more than 5 years, and the operational stability has been significantly improved.
4. Achieve precise oxygen supply and energy saving: The "One-to-Four" group design can adjust the supply of air volume according to the different oxygen consumption demands in different areas of the tank, avoiding insufficient or excessive aeration in certain areas, further reducing energy waste, and meeting the energy-saving and consumption reduction requirements of enterprises.
Project of the Sewage Treatment Station of Qinhuangdao Fuqingning Fengbang Paper Co., Ltd.
Basic Information: Located in the southeast of Shoulianding Town, covering an area of over 90 acres. It adopts the BOT investment operation model, with a total investment of approximately 150 million yuan. The influent water quality of the aeration system is as follows: CODcr ≤ 2000mg/l, BOD5 ≤ 800mg/l, ammonia nitrogen ≤ 50mg/l, total nitrogen ≤ 400mg/l, and the designed water volume is 1000m³/d. After biological treatment by our Guangbo Environmental Protection Equipment, the designed effluent quality reaches CODcr ≤ 400mg/l.
• Treatment Process: It adopts the biological treatment process of oxidation ditch + advanced treatment + ultraviolet disinfection. Among them, the Karusel oxidation ditch is the core part of wastewater treatment, using microorganisms in activated sludge to degrade organic pollutants in water. The central control room completes the automatic control of the entire plant and production management.
• Service Area: The service area covers the urban area of Fuqing County and the papermaking concentrated area of Shoulianding Town. The effluent meets the A standard of the "Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB18918 - 2002)".
