Avista, a global brand of Kurita for membrane treatment solutions

Yes. Increasing recovery typically requires the system to operate at a higher pressure, which increases energy use.

However, the actual impact depends on how the adjustment is made – especially whether you reduce feed flow, how the pump is configured (fixed vs variable speed), and the overall fouling state of the membranes.

Good pretreatment and clean membrane surfaces are essential to minimize energy increase when pursuing higher recovery.

For surfaces waters, a typical RO membrane lifespan is 4 to 5 years, sometimes even longer when well-maintained.

For wastewater or landfill leachate, shorter lifetimes are expected due to more challenging feedwater.

However, Kurita often extends membrane life through:

• Detailed foulant analyses
• Specialist cleaning routines
• Improved pretreatment
• Offsite membrane servicing

In many cases, a tailored treatment plan can significantly prolong membrane life beyond your current two-year cycle.

Potentially yes.

Kurita’s offsite membrane service evaluates each element individually, determining:

• Which membranes can be recovered
• Which can still operate in less demanding positions
• Which must be discarded

Many customers are surprised by how many elements remain usable after proper cleaning and diagnosis.

For most RO systems, the rule of thumb is:

• ~10 m³/h crossflow per 8-inch pressure vessel during cleaning.

Kurita also provides detailed cleaning guidelines to ensure optimal results, including soaking times, flushing sequences, and temperature considerations.

Longer membrane trains (e.g., six elements per pressure vessel) can be harder to clean effectively because:

• Fouling can migrate from one element to the next
• Crossflow velocity decreases along the length
• Early-stage elements receive better cleaning that downstream ones

Offsite cleaning solves this by treating each element individually, achieving much better results.

In most cases, a single well‑designed antiscalant can control multiple scale types simultaneously.
Kurita formulates products to handle combinations of:

• Calcium carbonate
• Calcium sulfate
• Silica
• Metal oxides
• Mixed salts

In extreme cases, pH adjustment or specialized formulations may be required — but 99% of systems can be protected with one optimized product.

Higher recovery = higher stress on membranes.

However, you can mitigate this by:

• Improving pretreatment
• Adjusting cleaning protocols
• Using appropriate anti-scalants at correct dosages
• Checking for seasonal water quality changes
• Monitoring scaling and fouling margins via software modelling

Moderate increases (e.g., 75% → 80%) are usually safe with proper preparation and monitoring.

Pushing beyond this requires careful engineering.

Kurita’s preferred solutions are membrane‑compatible biocides, such as:

• Kuriverter™ 110
• Kuriverter™ 220

These products:

• Are effective on existing biofilm (not just microbe killing)
• Are safer for membranes
• Do not create downstream nutrient loads
• Are often NSF‑approved

They offer a much better alternative to traditional chlorination.

A Kurita expert will:

• Visit your site
• Review all pretreatment steps (media filters, UF/MF, chemicals, backwashing, etc.)
• Analyze RO performance and fouling behavior
• Identify opportunities to save water, reduce energy, or increase production
• Provide tailored recommendations for improvement

This holistic approach ensures even subtle inefficiencies are captured.

Overdosing can cause several issues:

With coagulants:

• Excess solids accumulate in multimedia filters
• More frequent backwashing is required
• Coagulant can carry over to membrane stages
• Coagulant interferes with anti-scalants

With anti-scalants:

• Very high dosages can cause the anti-scalant itself to precipitate
• Cost increases without additional benefits

Correct dosage is just as important as correct product selection.

Fouling-resistant membranes can perform very well under specific conditions, especially with appropriate pretreatment and stable feedwater.

High-rejection membranes generally operate at higher flux, which can increase fouling risk.

Ultimately, performance depends on:

• Feedwater quality
• Pretreatment efficiency
• Biofilm control
• Scaling prevention
• Cleaning consistency

Membrane selection should be paired with system optimization.

Kurita generally advises caution with both oxidizing biocides upstream of RO.

While they can control microbes, they also:

• Break biological matter into nutrients
• Fuel downstream regrowth
• Promote EPS formation
• Increase fouling risks

Safer, membrane‑compatible, non‑oxidizing biocides are usually recommended.