Common Faults and Troubleshooting Methods in Industrial Ultrapure Water Ion Exchange Soft Treatment

Poor quality of regenerant (NaCl)

Use chemical analysis to test the quality of table salt and select qualified table salt.

Insufficient salt consumption leads to incomplete regeneration.

Increase the amount of sodium chloride (NaCl) salt used

Ion exchanger particles are contaminated by suspended solids.

The ion exchanger should be cleaned with clean filtered water and then air-washed. The pretreatment coagulation and filtration processes need to be improved to reduce influent turbidity.

The raw water contained high levels of valence metal ions such as Al3+ and Fe3+, which poisoned the ion exchanger.

The ion exchanger is periodically activated with 2-3% acid.

The concentration of the saline solution was too low.

Increase the concentration of the saline solution to 3-5%.

Damaged drainage system caused water to flow out of control.

Inspect the drainage system and refill the resin layer.

Insufficient or incomplete backwashing intensity

Careful operation, adjusting backwash pressure and water volume

The regeneration flow rate is too high, and the contact time with the ion exchanger is too short.

Adjust the regeneration flow rate to 3-6 m/h; or extend the regeneration time to one hour.

The washing process was not thorough, and residual regeneration solution was not rinsed off before entering the water tank.

Test the hardness of the backwash water to see if it meets the standard. If it does not, discharge the backwash water into the drain and do not allow it to enter the water tank.

If the forward washing time is too long, it will deplete the exchange capacity of the ion exchanger.

Adjust the water volume for the forward wash and control the forward wash time.

The ion exchanger layer height is too low

Increase the ion exchanger to make the layer height more than 1.5M.

Excessive resistance in the water inlet and drainage systems

Improve drainage and water intake systems to minimize head loss.

Damage to drainage pipes in the middle stage: Damaged drainage pipe mesh sleeve; Loose drainage pipe flange;

Replace the drain pipe; inspect and repair the mesh sleeve; tighten the drain pipe and flange;

The backwash intensity was too high, causing leakage of ion-exchanged organic compounds into the backflushing tube.

Reduce backwash intensity; install a feed mesh sleeve on the backwash discharge pipe.

Inside the exchanger, the velocity distribution across the exchanger cross-section is uneven, causing localized short circuits, and the exchanger is carried away by the water flow.

Improve the water distribution system, refill the ion exchange resin bed, and eliminate short circuits.

The exchange resin was of poor quality and had poor wear resistance, resulting in it being crushed and carried out by the backwash water.

Select ion exchangers with good wear resistance and high strength.

Excessive regeneration flow rate leads to high waste liquid discharge rate and waste of saline solution.

Adjust the regeneration flow rate and control the saline concentration.

Excessive mixing of salt water with other substances can cause it to surround the exchange resin, leading to a high consumption of salt water.

Improve the sedimentation and filtration system of brine, enhance rinsing intensity, and clean the exchange medium.

Damaged drainage device

Repair the drainage system, or install a resin trap on the soft water pipe.

The raw water has high levels of Ca2+ and Mg2+.

Two-stage softening

Valve leakage in regenerant system

Repair the valve to prevent leakage.

The outlet valve of the regenerating exchanger was not closed tightly, causing leakage of regenerated liquid.

Close or repair the water outlet valve.

Insufficient exchanger layer height; excessive exchange flow rate, resulting in incomplete exchange.

Increase the layer height of the exchanger and adjust the exchange flow rate.

Water temperature too low (below 5 degrees Celsius) results in poor water exchange.

Try to raise the water temperature to above ten degrees Celsius.

Switching operations or incomplete forward washing

Improve conversion or forward washing operation

Regenerant brine valve leak

Repair the brine valve

Operational errors, such as opening the brine valve at the water treatment plant but opening the outlet valve during regeneration.

Strengthen operational skills training and improve operational proficiency.