Most ion exchange resin can be polluted or mixed by the suspended substance. As PH changes, such relatively insoluble salts such as heavy carbonate bicarbonate will be precipitated. In addition, when absorbing or ion exchanging some substance, it is difficult for them to be removed by the normal recycled step. so it causes pollution on the resin.

      Normal washing can prevent the pollutant from being deposited and prolong lengthen the service life of the resin.

   Increasing recycled dosage and the recycled number of times (improve temperature ) can reduce pollution and prevent the permanent absorption of of inclusion.

   Making ion exchange resin and regenerant touch in the exchanger and adopting normal washing steps are extremely beneficial methods that the practice has verified.

   If these precautions have been already adopted, the equipment is not yet in good operation. You can consider one of the following reasons:

   (1)Resin amount was lost when the equipment was being operated.

   (2)he properties of supply water have changed. If the ion amount increases, the equipment powder is reduced proportionally.

   (3)Mistakes in operation. The recycled condition does not conform. with the rules

   (4)Something wrong with the hardware in the factory.

   (5)Resin being polluted or degraded.

    Of the above items, (4) is the most difficult one to judge. Item (2) can analyze water frequently. Item (3) is easy to be checked. If item (1),(2), (3), (4) are normal, we should take sample and analyze it.

• Resin sample
  

    Evaluate the resin and draw the conclusion. The most important thing is how to take a sample. The sample should be representative. If you are not sure about this, the sample should be provided by analyst.

Cleaning steps:

    According to the pollutant's performance, different steps are used to clean resin polluted.
This will be mentioned in this article.

• Steps of sterilization treatment
  

Preface

    The water source polluted sometimes enters the ion exchange system, the resin will be polluted by the bacterium or the alga. If the resin bed is found polluted, the following methods can be adopted:

peracetic acid

    Peracetic acid, the derivative of hydrogen peroxide, has wide table sterilization function to microorganism. It is proved in the research that peracetic has a wide range application in sterilization.

    Peracetic acid has the performance of broad-spectrum sterilization, so it is used as broad-spectrum bactericide

    Except very good sterilization function, peracetic acid has no to influence to the exchange performance of positive resin or negative resin.

    If peracetic acid is used as disinfectant, the following steps can be adopted no matter it is positive resin or negative:

1．If used in negative resin, resin will lose efficiency completely first. Peracetic acid should be used below PH8.

2． Prepare 1 bed layers of volume (BV ) (namely 1 / liters of resin ) pass the sour solution of second , the concentration is 2%

3．Pour into 1BV disinfectant, the velocity of flow is 5VB / hour, water replaced is got rid of from the underground drainage.

4．When all the peracetic acid is poured, close all valves , soak at least one hour

5．Wash out bactericide, use unboiled water, velocity of flow 5BV / hour, at least for 60 minutes, then wash for 30 minutes fast.

6．Recycle resin and put into operation

Formaldehyde

    If formaldehyde is used as disinfectant , the following steps can be adopted:

• Prepare 3 bed layers of volume (BV ) formaldehyde solution , dilute it into 80 times, adopt regenerant spray system make the concentration to 0. 5%.
• Inject 1BV bactericide, the velocity of flow is 5BV / hour, replaced water is got ride of from the underground drainage.
• If possible , drain off water to 50 mm. off the resin surface.
• Pour into 2nd 1BV bactericide solution,velocity of flow is the same as before.
• Wash and discharge with the unboiled water, until discharging point can't be tested out formaldehyde by Schiff test.
• Regenerate the resin two times (double regeneration), then put it into operation.

    Iron (and manganese ) pollution

Remedy methods:

Positive resin

    -Hydrochloric acid regeneration can be used. But hydrochloric acid resistant materials should be used inside the equipment pipes.Adopt 6% hydrochloric acid, use 3 bed layers of volume, keep hydrochloric acid and resin in touch for over two hour (better to be heated to 40 ℃). Then regenerate the resin two times use 10% salted water, then put into operation

Organic substance pollution and treatment

he most common method is using salted water. It is like the following:

• Resin can not be treated until it is invalid.
• Must prepare 3 beds and one layer of volume and 10% of the salt solution W/V first , including 2% of the NaOH W/V.
• Salt solution with a bed of volume, exchange bed with velocity of flow lower than 2BV/hour. Then enter second bed volume salt solution, keep it in bed, the longer, the better. no less than 4 hours. Stir it if it is possible.
• In the end, the salt solution of third bed layer of volume enters bed at the speed of 1BV / hour, then there is no salt solution existing in water.
• The resin must be regenerated completely at least after the second time, then put it into operation.

Precautions: