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Cartridge Filtration: Cleaning and Storing ScottCart Cartridges

Last Updated: 6/2021

Applies to: beverage producers using ScottCart Cartridge filters. It includes instructions for regeneration before storage, options for short- and long-term storage solutions, and cleaning instructions for ScottCart PES (polyethersulfone) and PP (polypropylene) filter media.

Cartridge Storage: How, Where, and In What?

Cartridge filters should be stored wet. It is a good idea not to let your cartridges dry out when storing them so that the materials remain pliable. Otherwise, they may become brittle and cause internal turbulence and premature damage during subsequent use. Cartridges should be properly prepped for storage and stored in the correct solution to maximize cartridge lifetime.

PRE-STORAGE REGENERATION

Before being stored, cartridge filters should be regenerated properly. Some pre-filter cartridges can be backflushed whereas some membrane cartridges cannot. You can still perform a forward flow regeneration to dissolve soluble compounds in the matrix if your cartridge is non-backflushable. Please check with Scott Labs or refer to the product technical data sheet whether your cartridge is backflushable or not.

A forward flow regeneration is completed as followed:

  1. Rinse with water at about twice the speed you were filtering at. Keep this high flow for 5-10 minutes
  2. Bring the water temperature up to no higher than 140⁰F and run for 5 minutes.
    1. NOTE: At temperatures warmer than 140⁰F, proteins lodged deeper in the matrix start to denature where they will stay and contribute to pressure buildup.
  3. Switch the pump off and close the valves so that your cartridge sits in this warm environment for 10-20 minutes.
  4. Bring the temperature back down incrementally by rinsing with cold water.
  5. Drain and store or drain and reuse. Alternatively, you can continue with a hot water or steam sanitization.

WHERE TO STORE CARTRIDGES

Cartridges can be stored:

  • Inside the housing
  • In a zipped plastic bag (10" Cartridges)
  • In a DIY storage container:
    • Use plumbing water piping and cap one end to make it leak proof.
    • Fill the tub with storage solution, stand the cartridges upright in the tube, and cap or cover with plastic wrap. Ensure cartridges are fully submerged.
    • Use a bungee cord to secure the containers to a barrel rack, wall, or table.

QUICK GUIDE TO STORAGE SOLUTION OPTIONS

SOLUTION TYPE

CONTACT TIMENOTES
Inexpensive Ethanol (Vodka)> Months*Keep strength above 20%/40 proof. *Do not use denatured spirits. *Purge out water very well before submerging to avoid lowering proof < 40 degrees. This is the preferred method of storing ScottCart Carbon Cartridges.
Nitric and Phosphoric Acid/BlendsMaximum 6 hours cumulativeUse at own risk. These acids damage the membrane structure at longer contact times.
Peracetic Acid at
0.05%
≤ 3daysAfter 3 days the peroxide in the formulation will have broken down, offering little protection against spoilage.
Storage at a higher concentration can lead to premature breakdown and/or damage of the media.
Citric Acid 1-2% Solution≤ 3daysAfter 3 days bacteria will target this solution. If bacteria is already present in the cartridge, then bacterial spoilage will begin within hours. See below for use with SO2
Citric Acid 1-2% in combination with 50-200 ppm SO2≥ 3 monthsCitric acid is commonly used in wineries with 50-200 ppm of added SO2 for long term storage. Periodically add more SO2 by dropping in an Inodose effervescent tablet.
SO Solution without Acidifying 50-200 ppm or ≤1000 ppm≥ 3 monthsThis is less effective than using SO2 with Citric Acid, however you can use up to 1000 ppm of SO2 which helps to bleach the media if your intention is to remove color. Periodically add more SO2 by dropping in an Inodose effervescent tablet.
Sulfuric Acid 2% Solution6 weeks +Recommended by the manufacturer for long term storage.
Caustic Soda (NaOH or KOH 1-2%)≤ 12 hoursCan be detrimental to some media types. Check with your supplier.
Ozone Water/GasNot recommended by the manufacturerInstant destruction of media.
Iodophor or other Iodine-based SanitizersNot recommended by the manufacturerPermanent staining and impossible to remove.

Storage Solutions Explained

For a more in-depth explanation of the suitability of each storage solution and contact time, please see below.

Inexpensive Ethanol* (Neutral vodka)

Cartridges can be stored in 40-135 proof ethanol solutions. Do not store cartridges in solutions greater than 135 proof, or the cartridge and storage container can prematurely age and crack. This storage solution is good for months to years as long as the proof doesn’t drop below 40 degrees/20% alcohol. This is the preferred method of storing ScottCart Carbon Cartridges.

Acid Sanitizers* (Nitric or Phosphoric Acid Blends)

This solution is typically recommended where there is a very short time-lapse (less than 3 days weekend) between filtrations. After this time, some acid sanitizers tend to break down (it becomes milky with a foul smell) and won't protect from microorganisms. Acid-based sanitizer solutions or oxidizing sanitizers are not recommended for long term storage.

*During storage in ethanol or acids, be sure to remove the O-rings between uses, as silicone tends to stretch and break up into little pieces when stored in these solutions long term.

Storage Under Pressure

Cartridges can be stored inside the housing under pressure for several months so long as the pressure does not drop below 1 bar. After regenerating, then steaming or hot water sanitizing them, then placing the drained housing under 1-1.5 bars (14.5-21.8 psi) with a food-grade gas like nitrogen. You may use CO2 but it is soluble and will take longer to build up the proper pressure.

Please take proper safety precautions when storing under pressure as many lenticular housings are only pressure rated for liquid pressure, not gas pressure.

Cleaning

This procedure applies ONLY to ScottCart  PES (polyethersulfone) and PP (polypropylene) filter media. This procedure does NOT apply to Dual Layer CA cartridges or ScottCart Carbon - consult product specific instructions.

For general cleaning of ScottCart PES and PP Cartridges, we recommend using Destainex-LF. It was specifically formulated for the wine industry to clean wine-related soil and neutralize microbial contaminants. This formulation removes protein and color stains via an oxidation process, and this non-hazardous fully ‘built’ cleaner rinses freely from equipment with a single pass rinse. It’s non-corrosive, non-tainting to wine and cider and is fully biodegradable.

INSTRUCTIONS

NOTE:  The procedure below only applies to ScottCart PES and PP cartridges.

Step 1: Prepare cleaning solution

  1. Add Destainex-LF to warm, moving water of approximately 104°F to 140°F (40°C–60°C). Recommended dosages are 0.75 – 1.5% v/v.
  2. Mix with a perforated paddle or with a motor impeller in a tank or container to provide the solution volume and allow the mixture to clarify (this takes only a few minutes). Excessive foaming may occur if the solution is not in full mixture.

Step 2: Circulate through filters

  1. Circulate at moderate pressure through the entire system to clean, making sure that the housing is properly vented. To force cleaning solution into all of the pores, the outlet valve can be slightly closed to bring the outlet pressure up to between 3psi-5psi for a few seconds.
  2. After the cycle, drain the solution and thoroughly conduct a single pass rinse with clean water and bring the backpressure up to between 3psi-5psi to ensure proper rinsing.
  3. pH test the wastewater stream with a digital meter or paper pH test strips from time to time to ensure that the waste stream is approximately pH 7.0/neutral. If the rinse water pH is at 8 or higher, you need to do an additional rinse or use an acid rinse like StarSan or Peracetic acid, both of which are sanitizers. Inspect and repeat if necessary.

A note on temperature:

Cleaning at lower or higher temperatures won’t improve the cleaning capability of the chemical. Protein char film is not expected to be present if the process is conducted with Destainex-LF on a regular basis.

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