JX Purification Reverse Osmosis Membrane Cleaning Techniques

JX Purification Reverse Osmosis Membrane Cleaning Techniques

Nanjing Junxin Environmental Technology Co.,Ltd manufacture Reverse osmosis membrane for many years. And JX purification specialized in technology to replace Dow BW30400, Toray TM7200D-400, Hydranautics RO as well. So today we want to introduce some technology of ro backwahs. Ro membranes cleaning is a delicate and complex task, and multiple cleanings can easily damage the membrane. The typical cleaning schedule is once every 3-12 months. If you clean every month, you need to improve pretreatment or redesign the RO water system; if you clean once every 1-3 months, you need to adjust and optimize the operation of your equipment.

Next let me show the cleaning of JX-RO membranes:

Tight Spacing Rough Surface

Salt Concentration in the Boundary Layer

FOULING

1. Poor Permeate Quality

2. Low Water Production

3. Membrane Damage

4. Frequent Cleaning

Principle Fouling Location

Fouling Indicators

Permeate Flow	Salt Passage	Diff. Pressure	Direct Cause	Indirect Cause	Corrective Measure
			Scaling	Poor Scale Control	Cleaning; Scale Control
			Colloidal Fouling	Insufficient Pretreatment	Cleaning; Improve Pretreatment
			Biological Fouling	Feed water; Insufficient Pretreatment	Cleaning; Biocide; Improve Pretreatment
			Organic Fouling	Polymer Overfeed; Humics; Oil	Cleaning; Improve Pretreatment

Membrane Preservation

    Preserve if out of service >24 hrs

Options:

Sodium Bisulfite 1%

Isothiazolone - PermaClean PC-56

Isothiazolone - PermaClean PC-55

Formaldehyde – carcinogen

Gluteraldehyde - membrane damage

Membrane Flushing

Permeate flush if system shuts down    

Acts as a “mini clean”    

Reduces fouling and scaling

Cleaning

RO’s need to be Cleaned!

Typically:

SDI 3 -5      Cleaning 4 /year

SDI 1- 3          Cleaning 2 /year

SDI < 1          Cleaning 1 /year

When do I clean?

When any ONE of the following changes:

Differential Pressure     by 15%

NPF     by 15%

Salt Passage     by 15%

Exceeding these limits may be irreparable

Start planning your strategy at the 1st indication of a minimum change!

Factors effecting Cleaning

Temperature

pH

Flow vs. Soak

Time

Velocity

Cleaning Tips

Pressure drop < 60 PSI

Flow 35- 40 GPM per pressure vessel (8”)

Cleaning Solution Volume: Use 8 - 10 Gallons Per 8” element. Each pressure vessel = 50 gallons volume

Use Alkaline cleaners first if organic fouling is suspected

Max Solution Temperature per Manufacturer

Soak Membranes

lean “stage by stage”

Replace Turbid / Murky Solutions

Keep good records

Don’t Panic

In summary, the cleaning condition of the JX-RO membrane can be detected at any time during the cleaning process, and the degree of cleaning can be decided according to the actual situation. By analyzing the main components of the contaminants in the cleaning solution, the contaminants of the system can be determined and the adjustment of the system can be proposed accordingly in order to prolong the service life of the customer's system.