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Improving CIP Effectiveness When Cleaning Results Are Poor

Guidance for cases where CIP runs successfully but recovery is limited

Improving CIP Effectiveness When Cleaning Results Are Poor

Subtitle:
What to check when a CIP cycle completes but cleaning performance does not improve

When to use this guide

Use this guide if a CIP cycle completes successfully, but the expected performance recovery is not achieved. Typical symptoms include:

  • Limited TMP recovery after CIP

  • Filtration flow does not improve as expected

  • CIP runs without alarms, but cleaning effect appears weak

This guide focuses on improving CIP effectiveness, not on how to start a CIP cycle.

Common misconception: CIP completed ≠ CIP effective

A completed CIP sequence does not necessarily mean that cleaning was effective.
In practice, the most common cause of poor CIP results is that the correct chemistry never actually reached the membranes, even though the automated CIP cycle ran as intended.

Step 1: Verify that chemical reached the membranes

This is always the first and most critical check when CIP results are poor.

The key requirement is that chemical was properly dosed, circulated, and passed through the filtration skid, ensuring contact with the membranes throughout the CIP cycle.

Checks to perform

  • Confirm chemical is present in the chemical container.

  • Verify that the CIP pump is primed and delivering flow.

  • Inspect chemical suction and delivery hoses for:

    • kinks

    • obstructions

    • air ingress

    • foot valve issues

  • Confirm that CIP flow is established through the filtration skid and membrane loop.

Recommended field verification

After chemical dosing is completed, verify chemical presence at the membranes by checking pH in the CIP circulation loop:

  • Acid CIP: approximately ~1

  • Base CIP: approximately ~12–13

If these pH levels are not reached approximately, cleaning effectiveness will be limited and the setpoints for chemical dosing percentage should be adjusted.

⚠️ Always follow MSDS guidelines and site safety procedures when handling chemicals and wear correct PPE. 

Step 2: Verify chemistry type and system configuration

Once chemical presence at the membranes is confirmed, verify the following:

  • Has the chemistry type recently been changed?

    • If yes, ensure the bulk concentration percentage has been updated in the system configuration page.

  • Confirm that the selected chemistry type is suitable for the expected fouling.

Running CIP with an incorrect or outdated configuration can significantly reduce cleaning effectiveness, even if the CIP sequence completes normally. Reach out to LiqTech if in doubt.

Step 3: Temperature considerations

Temperature can significantly influence CIP effectiveness, especially for Base CIP.

Before increasing temperature:

  • Verify whether the configured temperature setpoint was actually reached during the last CIP. If not the duration shall most likely be increased.

  • Confirm that measured temperature reflects the configured setpoint.

If additional cleaning effect is needed:

  • Increasing temperature to around 55 °C is often a reasonable next step if the previous setpoint was lower.

  • Approaching or exceeding 60 °C should only be done in consultation with LiqTech Service, as higher temperatures may increase wear on plastic components depending on system design.

Step 4: CIP duration and planning around downtime

In some cases, fouling severity or operating history means that additional CIP time is required.

If CIP results remain insufficient:

  • Consider increasing CIP duration.

  • Preferably plan extended CIP cycles during:

    • scheduled downtime

    • periods of reduced filtration demand

This allows improved cleaning effectiveness without impacting production availability.
In general it is highly recomended to CIP preemptively and even more so when scheduled downtime or periods of reduced filtration demand is relevant to your site. 

Step 5: Base and Acid CIP sequencing (including COMBI-CIP)

Different fouling types respond to different chemistries:

  • Base CIP typically targets:

    • organic fouling

    • biofouling

    • oils, fats, and proteins

  • Acid CIP typically targets:

    • inorganic scaling

    • carbonates

    • metal oxides

    • residual deposits after base CIP

Fouling can form in layers. In challenging cases, running Base CIP followed by Acid CIP can significantly improve results.

On newer LiqTech crossflow systems, this sequence is handled automatically via the COMBI-CIP function.
In particularly difficult and/or severe fouling cases, repeating the Base → Acid sequence once more may be beneficial.

When standard CIP chemistry is not sufficient

Some fouling types cannot be removed effectively using standard acid or base CIP.
Examples include certain sulfate scales (e.g. barium or strontium sulfate), which require specialized chelating chemistries.

Selection of alternative chemistries depends on:

  • temperature limitations

  • fouling type

  • system design and accessibility

👉 Always contact LiqTech Service before attempting non-standard CIP chemistries.

When to contact LiqTech Service

Please contact LiqTech Service if:

  • CIP effectiveness remains poor after confirming chemical presence at the membranes

  • higher temperatures or extended CIP durations are being considered

  • fouling is suspected to be outside the scope of standard acid/base CIP

  • guidance is needed on general behavior or system-specific limits