Specifying the Clean-In-Place (CIP) Mode for UF

This is similar to the specifying the Backwash and CEB Modes.

1. Number of Backwash (BW) steps within a CIP
2. CIP Source Water
3. CIP Recycle Flowrate
4. CIP Temperature
5. CIP Durations
6. CIP Mineral Acid Selection and Dose Specification
7. CIP Organic Acid Selection and Dose Specification
8. CIP Alkali Selection and Dose Specification
9. CIP Oxidant Selection and Dose Specification

The most thorough cleaning for a UF module requires the clean in place (CIP) process. The unit operations of a CIP involve:

1. An initial Backwash sequence
2. Soak and Backwash for each chemical used

3. The number of Backwashes for the CIP can be specified as shown in .

   

   Figure 1: The CIP specification window for UF modeling in WAVE

   Note:  By default, WAVE includes 2 backwashes within a CIP

CIP chemicals are circulated (recycled) through the UF fibers and housing to clean the system. This flowrate can be specified in the ¨Design¨ window as shown in Figure 4. From the recycle flow rate and duration, the user can calculate the volume of CIP chemicals needed per module.

Figure 3: The CIP Recycle Flow Rate modification

Notes:

• 2 m3/h/module is used as the default CIP recycle flowrate in WAVE. It is limited between 1 and 4.
• The effect of changing the CIP recycle flowrate is seen after WAVE models the UF system.

The CIP solution can be heated to improve its effectiveness at removing contaminants from the UF membrane. It has the same limits as CEB temperature (1-40°C). It can be specified as shown in Figure 4.

Figure 4: The CIP temperature specification window for UF modeling in WAVE

Note:  Currently the effect of different CIP temperatures on the system design (by affecting density/feed pressure) is not included in WAVE.

Three durations can be defined for CIP in WAVE (as shown in Figure 5):

1. Chemical Soaking duration – the amount of time the UF module is soaked in each chemical during CIP
2. Heating Step duration – the amount of time taken daily to heat the CIP chemicals from the UF system design temperature up to the CIP temperature ( to calculate energy consumption)

3. CIP Recycle duration – the amount of time during which the CIP solution is circulated through the UF module

   

   Figure 5: The CIP duration specification window for UF modeling in WAVE

Note:  Additional energy will be required to maintain the CIP temperature; however, that is outside the scope of WAVE.

WAVE allows for the addition of a mineral (i.e. inorganic) acid for CIP. This is done by following the steps below (Figure 6):

1. Click on the “Mineral Acid” button to activate it. The grey area would turn green.
2. Click on the dropdown arrow.
3. Select the mineral acid of interest.
4. Specify the target pH for pH reduction for CIP (if the ionic composition of the feed water is available) or target mineral acid concentration in the CIP stream.

5. Click over or tab to move elsewhere in the CIP Window.

   

   Figure 6: Specification of a Mineral Acid for CIP (a) Activating the Mineral Acid option (b) Selecting the Mineral Acid (c) Specifying the target pH in the CIP stream

The LSI value cell appears as a pH value is specified (note the difference between Figure 7 and Figure 8). The LSI (Langelier Saturation Index) is an indicator used to determine the need for calcium carbonate scale control. The LSI is applicable for water streams containing up to 10,000 mg/L of total dissolved solids (TDS). For water streams containing more than 10,000 mg/L of TDS, the Stiff & Davis Stability Index (S&DI) is preferred (as seen in Figure 9).

WAVE allows for the addition of an organic acid for CIP. This is done by following the steps below (Figure 10):

1. Click on the “Organic Acid” button to activate it. The grey area would turn green.
2. Click on the dropdown arrow.
3. Select the organic acid of interest.
4. Specify the target organic acid concentration in the CIP stream.

5. Click over or tab to move elsewhere in the CIP Window.

   

   Figure 10: Specification of an Organic Acid for CIP (a) Activating the Organic Acid option (b) Selecting the Organic Acid (c) Specifying the target concentration in the CIP stream

WAVE allows for the addition of an alkali for CIP. This is done by following the steps below (Figure 11):

1. Click on the “Alkali” button to activate it. The grey area would turn green
2. Click on the dropdown arrow.
3. Select the alkali of interest.
4. Specify the target alkali concentration in the CIP stream.

5. Click over or tab to move elsewhere in the CIP Window.

   

   Figure 11: Specification of Alkali for CIP (a) Activating the Alkali option (b) Selecting the Alkali (c) Specifying the target pH in the CIP stream

Figure 12: CIP Water quality in Alkali input in CIP with feed with no ionic composition

Figure 13: Changes Changes in Alkali input in CIP with feed TDS < 10,000 mg/L

Figure 14: Changes in Alkali input in CIP with feed TDS > 10,000 mg/L

WAVE allows for the addition of an oxidant for CIP. This is done by following the steps below (Figure 15):

1. Click on the “Oxidant” button to activate it. The grey area would turn green.
2. Click on the dropdown arrow.
3. Select the oxidant of interest.
4. Specify the target oxidant concentration in the CIP stream.

5. Click over or tab to move elsewhere in the CIP Window.