Recover valuable glaze from production wastewater instead of converting it into disposal sludge.
The PORVOO Rotary Ceramic Membrane Concentration System separates dilute glaze wastewater into two useful streams: reusable process water and concentrated glaze that can be returned directly to the glazing process.
Multiple low-speed rotating ceramic membrane discs operate inside a pressurized vessel. Positive pressure on the feed side and vacuum-assisted extraction on the permeate side create a total transmembrane pressure of 3–4 bar.
Typical glaze wastewater containing approximately 0.5 wt.% solids can be concentrated to 15–30 wt.% without adding coagulants, flocculants, or filter aids.
Principales ventajas
- Recover glaze for direct production reuse
- Produce reusable process water
- No discharged filter cake
- No coagulants or flocculants during concentration
- Automatic online backwashing
- Selectable membrane coatings down to 5 nm
- Capacity customized to each production line
Stop Treating Valuable Glaze as Waste Sludge
Glaze wastewater is commonly generated during ball-mill washing, spray-booth operation, equipment cleaning, and glaze-line rinsing.
In a conventional wastewater treatment process, this dilute stream is mixed with treatment chemicals, settled, and eventually converted into sludge. Valuable glaze raw materials are lost, while the factory must pay for chemical dosing, sludge handling, filter pressing, and disposal.
The PORVOO system changes this process.
Instead of treating glaze as a contaminant, it concentrates the suspended glaze solids into a pumpable material stream. Once the target concentration is reached, the recovered glaze can be discharged and returned to the original glazing process.
The permeate can be reused as process water wherever its quality meets the requirements of the intended production operation.
Two Recovered Streams from One Wastewater Feed
Recovered Glaze Concentrate
Dilute glaze wastewater enters the system at approximately 0.5 wt.% solids.
Water passes through the ceramic membranes, while glaze particles remain inside the concentration vessel. The solids concentration gradually increases until it reaches the target level of 15–30 wt.%.
The concentrated glaze remains pumpable. It is not converted into a dry filter cake and can be returned directly to the corresponding glaze production process.
Reusable Process Water
The liquid passing through the membrane is collected through internal channels in the ceramic discs and discharged through the hollow rotating shaft.
Part of the permeate passes through a dedicated polishing filter and is reused for automatic membrane backwashing. The remaining permeate can be reused as process water according to the factory’s production requirements and confirmed water-quality criteria.
How the System Works
1. Direct Glaze Wastewater Feed
Separately collected ball-mill washwater or spray-booth effluent can be fed directly into the system.
The concentration process does not require coagulation, flocculation, or chemical settling before membrane filtration.
2. Dual-Pressure Filtration
The glaze wastewater is held inside a positive-pressure vessel containing multiple ceramic membrane discs.
An independent vacuum pump creates negative pressure on the permeate side. The combined feed-side pressure and permeate-side vacuum generate a typical total transmembrane pressure of 3–4 bar.
This pressure difference drives water from the outside of each membrane disc into its internal permeate channels.
3. Low-Speed Membrane Rotation
The ceramic membrane discs rotate at low speed during operation.
The rotation helps:
- Keep glaze solids suspended
- Distribute feed evenly across the membrane surfaces
- Reduce localized solids deposition
- Maintain more stable filtration conditions
- Prevent premature formation of a thick surface layer
4. Outside-In Membrane Separation
The feed remains outside the ceramic membrane discs.
Water and components smaller than the selected separation layer pass through the membrane. Retained glaze particles remain in the vessel and become progressively concentrated.
The permeate flows through the porous support structure into the internal drainage channels and exits through the hollow shaft.
5. Automatic Online Backwashing
A portion of the permeate is polished through a dedicated filter and reused as the backwash medium.
Backwashing occurs during operation, reversing the flow through the membrane to remove deposited material from the membrane surface and pores.
Backwash cycles can be programmed on site. Differential-pressure- or flow-based automatic triggering is available as a customized control option.
6. Concentrate Discharge
The system operates as a batch concentrator.
When the glaze reaches the required solids concentration, the concentrated material is discharged and returned to the corresponding glazing process.
Why Ceramic Membranes?
The membrane discs use a ceramic support with a nano-coated separation layer.
The ceramic support has a nominal pore size of approximately 2.0 µm. Different membrane coatings can be selected according to the feed material, separation target, and required permeate quality, with available pore sizes down to 5 nm.
This configurable membrane structure allows the system to balance:
- Particle retention
- Permeate quality
- Filtration flux
- Concentration performance
- Cleaning requirements
Feed testing is used to determine the appropriate membrane coating and operating conditions for each application.
No Filter Cake—Concentration Instead of Dewatering
This system is not a filter press and is not designed to produce a dry cake.
Its purpose is to remove water while retaining the solids in a flowing, pumpable concentrate.
| Process Result | Conventional Sludge Treatment | PORVOO Membrane Concentration |
|---|---|---|
| Primary objective | Wastewater treatment and sludge disposal | Material recovery and concentration |
| Chemical dosing | Commonly required | No coagulants or flocculants during concentration |
| Solid output | Dewatered sludge or filter cake | Pumpable concentrate |
| Glaze recovery | Commonly lost as mixed sludge | Returned to the glazing process |
| Water output | Requires treatment before reuse | Permeate available for suitable process-water reuse |
| Membrane cleaning | No aplicable | Automatic online permeate backwashing |
| Modo de funcionamiento | Multiple treatment stages | Integrated batch concentration |
Verified Glaze Recovery Applications
Ball-Mill Washwater
Recover residual glaze solids from ball-mill washing instead of sending them into the general wastewater and sludge-treatment system.
Spray-Booth Effluent
Concentrate glaze overspray and washwater from glaze application areas for return to the appropriate glazing process.
Glaze-Line Cleaning Water
Recover glaze solids from separately collected equipment and production-line cleaning water.
Different glaze formulations, colors, and wastewater streams should remain segregated when the recovered concentrate is intended for direct production reuse.
Applications Beyond Glaze Recovery
The same concentration principle can be applied to other industrial wastewater streams using separate, dedicated equipment.
These streams must not be mixed with glaze wastewater intended for material recovery.
Ceramic Polishing Wastewater
Remove reusable water and reduce the volume sent to conventional chemical treatment, sedimentation, and filter pressing.
High-Solids Industrial Wastewater
Pre-concentrate suspended solids before an existing wastewater or sludge-treatment process.
Viscous Food-Processing Wastewater
Potential applications include wastewater containing sticky or difficult-to-filter suspended material.
Food-processing applications require feed testing and project-specific confirmation of wetted materials, hygienic design, cleaning procedures, and process requirements.
Other Process Suspensions
The system can be configured for other concentration duties where the objective is to recover water, reduce wastewater volume, or retain valuable suspended solids.
Suitability must be confirmed through feed characterization and filtration testing.
Reduce the Load on Conventional Wastewater Treatment
For wastewater streams where the concentrate cannot be returned to production, the system can be installed before the conventional treatment process.
The membrane system first removes reusable water and reduces the wastewater to a smaller concentrate volume.
Only the concentrated stream then enters:
- Chemical dosing and flocculation
- Sedimentación
- Filter pressing
- Sludge handling or disposal
This reduces the hydraulic volume handled by downstream equipment and allows the existing wastewater-treatment system to focus on a smaller, more concentrated stream.
Automatic Backwashing and Periodic CIP
Automatic permeate backwashing reduces routine membrane cleaning and helps maintain filtration performance during operation.
The standard system allows the backwash cycle to be programmed on site. Custom automation can trigger backwashing according to differential pressure, permeate flow, or other operating conditions.
Periodic acid cleaning is still required to restore membrane performance when necessary.
In the standard configuration, operators prepare the acid-cleaning solution and initiate the cleaning cycle. Automated CIP preparation and control can be supplied as a customized option.
The system should therefore be described as automatically backwashed, not maintenance-free.
Technical Parameters
| Parámetro | Standard Description |
|---|---|
| Product type | Rotary ceramic membrane concentration system |
| Primary application | Glaze wastewater concentration and recovery |
| Modo de funcionamiento | Batch concentration |
| Membrane configuration | Multiple low-speed rotating ceramic membrane discs |
| Vessel configuration | Positive-pressure filtration vessel |
| Permeate extraction | Independent vacuum pump |
| Filtration direction | Outside-in |
| Typical total TMP | 3–4 bar |
| Ceramic support pore size | Approximately 2.0 µm |
| Separation layer | Selectable nano-coated membrane |
| Finest available pore size | Down to 5 nm |
| Typical glaze feed solids | Approximately 0.5 wt.% |
| Target concentrate solids | 15–30 wt.% |
| Concentrate form | Flowable, pumpable glaze concentrate |
| Backwash medium | Polished permeate |
| Backwash control | Field-programmable cycles |
| Custom backwash control | Differential-pressure- or flow-based triggering |
| Periodic membrane cleaning | Acid CIP |
| Standard CIP operation | Operator-prepared and operator-initiated |
| Treatment capacity | Customized to feed properties and production volume |
| Process additives | No coagulants, flocculants, or filter aids during concentration |
Actual performance depends on feed composition, viscosity, temperature, particle-size distribution, selected membrane coating, and target concentration.
System Engineering and Customization
Each system is configured according to the customer’s process rather than selected only by nominal flow rate.
PORVOO evaluates:
- Wastewater source
- Daily and hourly feed volume
- Initial solids concentration
- Target concentrate solids
- Particle-size distribution
- Feed viscosity and temperature
- Required permeate quality
- Intended concentrate reuse route
- Required membrane area
- Backwash control strategy
- Available utilities
- Installation space
- Automation requirements
Pilot or sample testing may be required for new materials and high-viscosity applications.
Preguntas frecuentes
Does the system produce a filter cake?
No. The system produces a flowable concentrate rather than a discharged, dewatered filter cake.
Can recovered glaze be reused directly?
Yes. When the glaze wastewater is collected separately and kept within the corresponding formulation or production stream, the concentrate can be returned directly to the glazing process.
Are flocculants or coagulants required?
No coagulants, flocculants, or filter aids are added during the membrane concentration process.
Periodic acid cleaning is required for membrane maintenance and should not be confused with chemical dosing into the wastewater.
How is the membrane cleaned during operation?
Polished permeate is automatically reversed through the membrane during online backwashing. The standard backwash timing can be programmed on site.
Is manual cleaning completely eliminated?
Routine manual membrane-surface cleaning is reduced by online backwashing. However, periodic acid CIP requires operator preparation and initiation in the standard configuration.
Can the permeate be reused?
Yes, the permeate can be reused as process water where its measured quality meets the requirements of the intended operation.
Can different wastewater streams be mixed?
Different streams should use separate collection and dedicated treatment systems.
Glaze wastewater intended for direct glaze recovery must not be mixed with polishing wastewater, domestic wastewater, or unrelated industrial streams.
Can the system handle food-processing wastewater?
Potentially, subject to feed testing and confirmation of hygienic design, wetted materials, cleaning requirements, and the intended use of the recovered streams.
How is the system capacity selected?
Capacity and membrane area are engineered according to feed properties, daily wastewater volume, target concentration, and required batch time.
Recover the Material You Already Paid For
Glaze wastewater does not have to become disposal sludge.
PORVOO can configure a rotary ceramic membrane concentration system that recovers glaze for production reuse, returns water to suitable plant operations, and reduces dependence on conventional chemical sludge treatment.
To evaluate your application, please provide:
- Wastewater source
- Daily wastewater volume
- Current solids concentration
- Target concentrate solids
- Glaze type or other suspended material
- Required process-water quality
- Available installation space and utilities
