Before Designing a Ceramic Membrane System, What Data Do We Need?

Two projects both need to daily treat 5,000 m³ water. Does that mean they require the same membrane area and system configuration?

Not necessarily.

• Project A is a new surface-water treatment project with stable water quality, sufficient construction space, 12-hour operation, and suspended solids and turbidity as the main treatment targets.
• Project B is an industrial wastewater renovation project with limited installation space, fluctuating COD, oil, and suspended solids, 24-hour continuous operation, and stricter treated-water requirements for reuse.

Although their daily treatment capacity is identical, differences in site restrictions, raw water quality, effluent requirements, operating hours, and existing infrastructure can change the process route, membrane sizing, equipment configuration, and operating strategy.

Depending on the raw water and treatment objective, the ceramic membrane may be used for direct physical separation in a submerged UF system or as the solid-liquid separation unit in an MBR process. We have discussed these two routes in previous content, so we will not repeat their differences here.

Instead, we will use Projects A and B to show what information must be confirmed before system design—and how each input changes the final solution.

1. Available Footprint: Same Capacity, Different Layouts

Available space affects not only the equipment footprint but also the construction type, maintenance access, and potential for future expansion.

Project A — Flexible civil construction

As a new project with sufficient space, Project A can use civil tanks designed around the selected process. Membrane modules, pumps, pipelines, and maintenance areas can be arranged with fewer existing constraints, while additional space can be reserved for future capacity expansion.

Project B — Compact integration within an existing site

Project B must fit into an existing industrial site with restrictions on length, width, height, access, and lifting conditions. Existing tanks, pipelines, and electrical connections may also need to be reused. An integrated or skid-mounted system can reduce the footprint, but sufficient space must still be reserved for membrane-module removal, equipment maintenance, chemical cleaning, and safe operation.

The result: Project A prioritises layout flexibility and future expansion, while Project B prioritises compact integration and compatibility with existing infrastructure.

2. Raw Water Quality: Same Capacity, Different Operating Risks

Raw-water classification alone does not provide enough information for design. “Surface water” or “industrial wastewater” describes the source, but not the actual treatment difficulty.

Project A — Stable and predictable solids loading

Project A has relatively stable suspended solids and turbidity. With a predictable water-quality range, its pretreatment, operating flux, and cleaning strategy can be designed around a relatively consistent membrane load.

Project B — Variable and process-dependent water quality

Project B’s wastewater may change with production batches, raw materials, equipment cleaning, and discharge periods. A representative water-quality report should therefore include at least COD, pH, suspended solids, ammonia nitrogen, turbidity, oil, and silica, together with typical and peak values. Depending on the production process, temperature, hardness, conductivity, salinity, and specific contaminants may also be relevant.

These parameters lead to different engineering decisions. Oil can create a difficult fouling layer, high suspended solids may shorten filtration cycles, and silica or hardness may increase scaling risks under certain conditions. COD and ammonia nitrogen also help determine whether physical separation is sufficient or whether biological or other treatment stages are required.

An average value may hide the most demanding operating condition. For example, Project B may have moderate suspended solids during normal production but a much higher concentration during equipment cleaning. Designing only around the average could underestimate the peak membrane load.

The result: Project A allows a more predictable operating strategy, while Project B may require water-quality equalisation, additional pretreatment, a more conservative flux, or pilot testing.

3. Effluent Requirements: Same Capacity, Different Roles for the Membrane

The required effluent quality determines what the ceramic membrane must achieve and whether additional treatment stages are needed. A description such as “for reuse” is not yet a complete design specification.

Project A — Suspended solids and turbidity control

Project A mainly requires the removal of suspended solids and the control of turbidity. The ceramic membrane can therefore serve as the principal physical separation barrier, producing stable clarified water without an unnecessarily complex process.

Project B — Water quality defined by the reuse application

Project B requires water reuse, but the appropriate treatment process depends on how the water will be used. Water for general washing may have relatively straightforward requirements, while reverse-osmosis feed or water returned to a sensitive production process may require much stricter control.

Ceramic membranes can effectively retain suspended particles and colloidal matter. However, clear permeate does not mean that dissolved COD, ammonia nitrogen, hardness, salinity, or other dissolved substances have been removed.

Depending on the specific reuse standard, Project B may therefore require upstream biological or physicochemical treatment, additional downstream treatment, or both.

The role of the membrane is determined not only by the raw water but also by the required destination and quality of the treated water.

The result: In Project A, the ceramic membrane performs the main physical separation task. In Project B, it may serve as one part of a broader treatment and reuse process.

4. Operating Time: Same Daily Capacity, Different Hourly Loads

Daily treatment capacity does not show the actual load that the system must handle each hour.

• Project A — 12-hour operation
• 5,000 ÷ 12 ≈ 417 m³/h

Its relatively short operating window requires a higher hourly treatment rate. If no buffer capacity is provided, the membrane system, pumps, pipelines, and other hydraulic equipment must all be sized for this higher instantaneous load.

• Project B — 24-hour continuous operation
• 5,000 ÷ 24 ≈ 208 m³/h

Continuous operation reduces the average hourly load. However, because industrial wastewater may still arrive in batches or fluctuate with production, equalisation may be required to provide a stable feed to the treatment system.

These figures represent theoretical average production rates. The final design capacity must also allow for relaxation, backwashing, chemical cleaning, maintenance, and other periods when the membrane is not producing water.

The result: Although both projects treat 5,000 m³/day, Project A requires approximately twice the average hourly capacity. Operating hours therefore affect membrane sizing, pump and pipe selection, tank volume, and overall system configuration.

From Project Data to a Practical Design

The comparison between Projects A and B shows how the same treatment capacity can create different design priorities.

Project A has stable raw water and sufficient construction space, but its 12-hour operating window requires a higher hourly treatment capacity. Project B operates continuously at a lower average flow, yet its restricted site, variable industrial wastewater, and reuse target create greater process and operational complexity.

Before developing a proposal, three inputs must therefore be confirmed:

• Available footprint: actual site dimensions, access conditions, maintenance space, and existing infrastructure.
• Raw water quality: representative data covering both typical and peak conditions.
• Effluent requirements: measurable discharge limits or specific water-reuse targets.

These are not simply questionnaire items. They determine the layout, process route, role of the membrane, operating strategy, and level of treatment required.

Project type, existing treatment units, operating hours, peak flow, filtration mode, and future expansion requirements can then be used to complete the detailed sizing and configuration.

A good proposal should connect every major design decision to verified project conditions—not fill the gaps with convenient assumptions.

Treatment capacity tells us how much water must be treated. Project information tells us how the system should be designed.