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 critical factor in the construction of wastewater treatment facilities, as it directly affects the effectiveness of the system and helps reduce operational costs. Therefore, it's essential to consider the design scale, the characteristics of the wastewater, and local conditions and requirements when choosing a technically feasible, economically reasonable, and environmentally friendly treatment technology. A comprehensive technical and economic analysis should be conducted to determine the best overall process plan and implementation method. Dongguan environmental experts emphasize several key principles when determining the overall process plan for wastewater treatment systems:
1. The technology should be advanced and mature, with strong adaptability to changes 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 process should aim to minimize infrastructure investment and operating costs, save space, and reduce energy consumption.
4. Efforts should be made to reduce negative environmental impacts such as odors, noise, and aerosols.
5. The system should be easily automated to improve management efficiency and operational control.
Process Selection: Drawing from previous experience in treating waste papermaking wastewater, some water quality requirements in the pulping system are relatively low—COD below 1500 mg/L and SS below 200 mg/L are acceptable for reuse. To reduce investment and processing costs, the plan involves using a micro-porous hydraulic sieve and air flotation to treat a total of 8,000 cubic meters per day. Out of this, 3,000 cubic meters per day can be directly reused in the pulping system, meeting the process requirements. The remaining 5,000 cubic meters per day undergoes biological treatment, with part of it recycled into the papermaking system and the excess discharged to meet standards. As a result, the plant’s overall wastewater reuse rate reaches 75% (6,000 cubic meters per day), which is among the highest in China.
The treatment process combines physical-chemical and biochemical methods, with wastewater classified according to its quality and reuse requirements. A microfiber hydraulic screen is used to recover usable paper fibers. After removing suspended solids via a primary air flotation unit, 3,000 m³/day of wastewater is reused in the pulping process, while the remaining 5,000 m³/day flows by gravity to a biological contact oxidation tank. An aeration system is installed, along with filler media where microorganisms break down organic matter, ammonia nitrogen, and color. The effluent then enters a secondary coagulation air flotation unit, where a pipeline mixer ensures thorough mixing with chemicals before flotation and separation occur in the air flotation tank. The final effluent is collected in a clear water tank, meeting the national first-class discharge standard and the water quality requirement for papermaking.
Sludge from both the primary and secondary air flotation units is sent to a sludge storage tank. Regularly, the sludge is transported to a dewatering unit, after which it is disposed of properly. The treated effluent is either reused or discharged as needed.
Keywords: Dongguan Waste Gas Treatment, Dongguan Wastewater Treatment, Dongguan Noise Control, Dongguan Dust Control
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