Views: 315 Author: Site Editor Publish Time: 2024-04-02 Origin: Site
| Wastewater Type | Nonwoven spunlace wastewater treatment |
| Implementation time | |
| Product name | RDAF High Efficiency Dissolved Air Flotation |
| Processing scale | 120m3/H |
| Project name | Hangzhou Nuobang Nonwoven Fabric Project |
| Process |
Hangzhou Nbond Nonwovens Co., Ltd, founded in 2002(stock code:603238), was invested by Hangzhou Robam Industrial Group. On 22 February 2017, it went public on the Shanghai Stock Exchange(SSE). It owns 12 advanced spunlaced nonwoven production lines and is the first experiment line for spunlaced nonwoven material built by the company in China.
1. Production process drainage. Each spun lace production line uses 200m3/h of water; the circulating water volume is as high as 4800m3/d. Each spunlace production line has a set of circulating water treatment facilities to treat the circulating water required by the spunlace production line. The standard circulating water treatment process is shown in Figure 1. The circulating water treatment process description: The circulating water containing suspended matter enters the regulating tank for water quality and quantity adjustment, balances the water quality, and pumps the circulating water into the dissolved air flotation machine through the lifting pump to remove most fibers. After secondary lifting in the water storage tank, it enters the tertiary filter to remove the suspended matter in the water further. Finally, it is treated by the ultrafiltration equipment and reused for production.
Picture 1 Circulating water treatment process of spunlace production line
The circulating water treatment facilities must be flushed regularly to ensure circulating water quality. Since each enterprise uses different water circulation processes and has different management levels, the amount of flushing wastewater and flotation skimming (production wastewater) generated by each set of circulating water treatment facilities is generally 240-720m3/d, which means that the recycling rate is only 85-95%. The indicators of discharged wastewater are shown in Table 1.
2. High-pressure pump cooling water. High-pressure pumps are generally water-cooled, and each production line produces about 2 to 4 m3/h of cooling water.
| Project | pH | CODcr/(mg/L) | BOD5/(mg/L) | SS(mg/L) |
| Wastewater | 5.0~7.5 | 30~240 | 8~90 | 10~285 |
| Emission Standards | 6~9 | <100 | <30 | <70 |
Table 1 Wastewater discharge indicators
In this project,air flotation is used for pretreatment to reduce the content of organic matter and suspended matter in the landfill leachate. After the pretreatment of air flotation, the removal rate of suspended matter concentration is more than 90%. The removal rate of oil and grease is more than 95%, and the burden of subsequent biochemical treatment is significantly reduced. The concentration of landfill leachate is generally high, and it is recommended that vortex air flotation plus dissolved air flotation be used for better treatment.
