Application of Filter Presses in Zinc Plating Liquid Treatment
Zinc plating is widely used in the steel, hardware, fastener, automotive parts, and metal surface treatment industries. During production, zinc-containing wastewater, rinsing wastewater, and other metal surface treatment wastewater are generated.
This type of wastewater typically contains zinc ions and a certain amount of suspended solids. After pH adjustment, neutralization, precipitation, and flocculation, the dissolved metal ions are converted into solid precipitates, forming sludge with a certain solid content. Next, a filter press separates solids from liquid, further reducing sludge moisture and separating the filtrate for further treatment.
Why is a Filter Press Needed for Galvanizing Wastewater?
Galvanizing wastewater, after chemical treatment, typically produces a large amount of fine metal hydroxide precipitates. If left to settle naturally, the sludge will have a high water content, requiring significant storage space and increasing subsequent transportation and treatment costs.
A filter press uses feed pressure to transport sludge into the filter chamber, where solid-liquid separation is achieved through the retention of the filter cloth.
Functions:
- The solid forms a filter cake, facilitating centralized collection and subsequent treatment;
- The filtrate is discharged from the drain holes of the filter plate and enters subsequent water treatment processes;
- It reduces sludge volume and water content, lowering storage and transportation pressures;
- It improves the continuous operation capability of the entire wastewater treatment system.
Morocco Galvanizing Industry Case Study
One of our Moroccan clients is engaged in metal galvanizing production and needed solid-liquid separation for the sludge generated during the galvanizing process.
Based on the client’s processing volume and on-site requirements, we configured a 70 square meter filter press for them:
- Filtration Area: 70 square meters
- Application: Galvanizing liquid treatment
- Control System: PLC automatic control
PLC automatic control system
The equipment is equipped with a PLC control system, which can centrally control the main operating steps such as compaction, feeding, pressure holding, and release.
Compared to relying entirely on manual operation, PLC control can:
- Simplify the operation process;
- Improve equipment operating stability;
- Reduce manual workload;
More easily integrate with the customer’s existing wastewater treatment system.
Drip tray device
During the filter press filtration process, a small amount of dripping liquid may occur between the filter plates. When the drip tray is closed, it catches the liquid generated during filtration, preventing it from dripping directly onto the filter cake area or below the equipment. During unloading, the drip tray automatically opens, allowing the filter cake to fall normally.
For galvanizing wastewater treatment sites, the drip tray helps to:
- Collect dripping liquid during filtration;
- Keep the area below the equipment clean;
- Reduce waste liquid contamination of the unloading area;
- Facilitate centralized collection of filter cake;
- Increase the automation level of the entire sludge treatment area.
Advantages of Filter Presses for Zinc Plating Wastewater Treatment
Filter presses offer mature solid-liquid separation capabilities for zinc-containing sludge after neutralization and sedimentation.
Key advantages include:
- Effectively trapping fine solid particles in sludge.
- Reducing free water in the sludge through mechanical pressure filtration, thus lowering the filter cake volume.
- The resulting filter cake facilitates collection, transportation, and subsequent treatment of solids.
Conclusion
In galvanizing and metal surface treatment wastewater systems, filter presses primarily handle solid-liquid separation and dewatering of sludge after chemical treatment. A well-designed filter press configuration can reduce sludge volume, improve solid-liquid separation efficiency, and facilitate subsequent filter cake collection and wastewater treatment.
If you need to select a filter press for galvanizing, electroplating, or other metal surface treatment wastewater, please feel free to contact us.