ZHITONG PIPE VALVE TECHNOLOGY CO.,LTD , https://www.ztongvalve.com
Be wary: the principles followed in the paper industry wastewater process cannot be ignored
Be cautious: the principle of wastewater treatment in the paper industry should not overlook the selection of the process plan. This is a crucial factor in the construction of wastewater treatment facilities, as it directly impacts the effectiveness of the system and helps reduce operational costs. Therefore, it's essential to consider the design scale, characteristics of the wastewater quality, and local conditions and requirements when choosing a technically feasible, economical, and rational treatment technology. A comprehensive technical and economic analysis should be conducted to determine the most suitable overall process plan and implementation method.
Dongguan environmental experts have emphasized several key principles for determining the overall wastewater treatment process:
1. The technology should be advanced and mature, with strong adaptability to fluctuations in water quality and stable operation. It must ensure that the treated water meets both factory use standards and national discharge regulations.
2. The system should be easy to operate and manage, allowing for flexible adjustments based on the inflow water quality and quantity.
3. The plan should aim to minimize infrastructure investment and operating costs, save space, and reduce energy consumption.
4. It should minimize negative environmental impacts such as odors, noise, and aerosols.
5. The system should be easily automated to improve operational efficiency and management.
Process Selection: Drawing from past experience in treating waste papermaking wastewater, some systems do not require extremely high water quality. As long as the COD is below 1500 mg/L and the SS is under 200 mg/L, the water can be reused. To reduce investment and processing costs, the selected plan involves treating 8,000 cubic meters of wastewater daily using micro-porous hydraulic screening and air flotation. Of this, 3,000 m³/day is directly reused in the pulping system, meeting the required process standards. The remaining 5,000 m³/day undergoes biochemical treatment, with part of it recycled into the papermaking system and the excess discharged to meet standards. This results in an overall reuse rate of 75% (6,000 m³/day), which is among the highest in China.
The treatment process combines physical-chemical and biological methods, with wastewater classified according to its quality and reuse requirements. Microfiber hydraulic screens are used to recover usable paper fibers, while the first-stage air flotation removes suspended solids. Part of the treated water (3,000 m³/day) is then reused in the pulping process, and the rest (5,000 m³/day) flows by gravity into a biological contact oxidation tank. An aeration system and filler media are installed to support microbial degradation of organic matter, ammonia nitrogen, and color.
The effluent from the contact oxidation tank enters a secondary coagulation air flotation unit. A pipeline mixer is used before the air flotation to ensure thorough mixing and reaction with chemicals. The air flotation process separates the impurities, and the clarified water flows into a clear water reservoir. The water quality meets the national first-class discharge standards and the water production requirements for papermaking.
Sludge from both primary and secondary air flotation units is collected in a sludge storage tank and periodically sent to a dewatering device. The dewatered sludge is then transported for disposal. The treated effluent is either reused or discharged after meeting all regulatory standards.
Keywords: Dongguan Waste Gas Treatment, Dongguan Wastewater Treatment, Dongguan Noise Control, Dongguan Dust Control
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