Backwash Filter & Cartridge Filter Solutions for an Irish Construction Industry Client

Application Background

Our client from Construction industry client based in Ireland, required a filtration solution for their rinsing process. The water to be filtered is RO permeate, used as the final rinse water. Upstream of this final tank (Tank No. 8), there are seven preceding tanks. Tanks No. 1 and No. 2 contain etching residues, while the subsequent tanks hold other process waters. The line involves aluminum immersion treatment, which causes particulate matter to carry over from one tank to the next, ultimately reaching the final rinse tank (No. 8).
Since the system has not yet been put into operation, the exact solids content in the water remains unclear at this stage.

Initial Recommendation & Budget Adjustment

Filtration requirement:

Filtration accuracy: 5–10 microns
Flow rate: 20 m³/h

Our initial recommendation was the Model 400 self-cleaning backwash filter. However, the client indicated that this exceeded their budget. We therefore proposed an alternative – if a 10-micron accuracy is acceptable, the smaller Model 300 could be a more cost-effective solution without compromising performance.

Key Technical Clarifications Provided to the Client

During the discussion, we addressed several important questions from the client:
1. Backwash water source
Our backwash filter uses its own filtered water for the cleaning cycle. No external water supply is required.
2. Manual vs. automatic backwash
The system supports both manual and automatic backwash modes. However, for normal operation, automatic mode is mandatory. If left in manual mode, operators may fail to notice the pressure differential caused by solids accumulation, which could lead to irreversible damage to the filter screen. The automatic function ensures the filter cleans itself precisely when needed, protecting the screen while maintaining continuous operation.
3. Backwash water consumption
The amount of water consumed during backwashing depends on the solids loading. The lower the solids content, the less water is consumed – making the system highly efficient in cleaner applications.

Additional Filtration Requirement – Cartridge Filter vs. Bag Filter

After confirming the backwash filter solution, the client raised a new request: they needed filtration for another tank. This tank contains a different type of water, which is relatively clean. While filtration is not strictly necessary, the client felt that polishing the water would be beneficial for process reliability.
The client asked for our recommendation: bag filter or cartridge filter?
Our recommendation: We advised the cartridge filter for the following reason:

Cartridge filters offer a filtration efficiency of up to 98% , which is significantly higher than that of bag filters.
For the same flow rate of 20 m³/h, we recommended a 10-40"(P)-Cartidge Filter Housing.

Additional Notes on Cartridge Filter Lifespan

We also provided the client with realistic expectations regarding filter cartridge service life:

Cartridge life is closely related to water quality and daily water consumption.
In applications with clean water, the cartridges last longer; in dirtier applications, the lifespan is shorter.
As a general reference, for 1-micron and 5-micron cartridges, the typical service life is approximately 6 months under normal operating conditions.