Views: 508 Author: Site Editor Publish Time: 2024-03-18 Origin: Site
| Wastewater Type | Textile printing and dyeing wastewater |
| Implementation time | |
| Processing scale | Added 100t/H |
| Project name | Egypt printing and dyeing wastewater renovation project |
| Product name | RDAF High Efficiency Dissolved Air Flotation |
| Process | Using air flotation + biochemical + air flotation combined upgrading process to treat printing and dyeing wastewater |
An Egyptian printing and dyeing company mainly engages in the
dyeing and finishing of polyester-cotton series, all-polyester series, acrylic series, and blended fabrics, with an annual printing and dyeing capacity of 70 million m3. Starting in 2019, based on the production situation at the time, the company successfully equipped and operated wastewater treatment facilities with a daily processing capacity of 1,200 and 1,400 t/d. The company upgraded the existing wastewater treatment facilities to implement the new emission standards.
Enterprise wastewater is production wastewater and factory domestic sewage. Production wastewater mainly includes dyeing wastewater and alkali reduction wastewater. Dyeing wastewater: design water volume 2000 t/d, pH 7-8, COD 1800 mg/L, ammonia nitrogen mass concentration 30 mg/L, SS mass concentration 300 mg/L, chromaticity 200 times; alkali reduction wastewater: design water volume 200 t/d, pH>14, COD 10000 mg/L, ammonia nitrogen mass concentration 30 mg/L, SS mass concentration 200 mg/L, chromaticity 1000 times.
The main structures of the existing process wastewater treatment project are shown in Table 1. The company has built two wastewater treatment facilities with treatment scales of 1,200 t/d and 1,400 t/d, respectively. The treatment process of 1,200 t/d is: wastewater→grid→regulating tank→reaction sedimentation tank→facultative oxygen tank→biological contact oxidation tank→secondary sedimentation tank→flotation tank A→external discharge pipe.
The existing treatment process of 1,400 t/d is: wastewater→grid→regulating tank→dosing primary sedimentation tank→biological contact oxidation tank→secondary sedimentation tank→flotation tank B→external discharge pipe. Flotation tank B, one treatment capacity is 100 t/h.
The designed inlet and outlet water quality and the actual inlet and outlet water quality are shown in Table 1
| Water quality indicators | pH | COD/(mg·L-1) | BOD5/(mg·L-1) | ρ/(mg·L-1) | ||
| SS | NH3-N | TP | ||||
| Designed water inlet | 8~9 | 2000 | 600 | 300 | 50 | 8.0 |
| Actual water inlet | 9~11 | 3000 | ≈900 | 300 | 50 | 6.0 |
| Designed water outlet quality | 6~9 | 500 | 300 | 300 | 35 | 8.0 |
| Actual water outlet | 6~9 | 400~500 | ≈80 | 100 | ＜5 | ＜0.5 |
Table 1 The designed and actual water quality in and out of the wastewater
The total designed water volume of the project is 2 400 m3/d, all of which will be discharged into pipes. After the project is upgraded, the designed inlet and outlet water quality indicators are shown in Table 2
| Parameters | Designed inlet water quality | Designed discharge water quality |
| pH | 6～9 | 6～9 |
| COD/(mg·L-1) | 3000 | 200 |
| BOD5/(mg·L-1) | 900 | 50 |
| ρ(SS)/(mg·L-1) | 300 | 100 |
| ρ(NH3-N)/(mg·L-1) | 30 | 20 |
| Chroma / times | 800 | 80 |
Table 2 The designed water quality of inflow and effluent
The process flow of upgrading the original sewage station is shown in Figure 1.
Figure 1 The reformation process of sewage station
After the production wastewater is discharged from the workshop, it flows into the regulating tank by gravity. After the water volume and quality are balanced, it is lifted by a pump into the reaction tank. After being treated by the high-efficiency dissolved air flotation produced by our factory, the clean water enters the biochemical treatment system, and the sludge enters the thickening tank.
Our factory's high-efficiency dissolved air flotation tank has a good treatment effect, high removal efficiency, and low sludge production. It can remove the residual colloids, insoluble organic matter, and most of the suspended solids from the effluent of the secondary sedimentation tank.
