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Factors affecting the system operation of EDI water treatment equipment
Author:Dongda Environment Time:2020-12-23 Clicks:187
       1. The influence of EDI inlet water conductivity.
       Under the same operating current, as the conductivity of raw water increases, the removal rate of weak electrolyte by EDI decreases, and the conductivity of effluent water also increases. If the conductivity of the raw water is low, the content of ions is also low, and the low concentration of ions makes the electromotive force gradient formed on the surface of the resin and the membrane in the shallow chamber also large, resulting in an increase in the degree of water dissociation, an increase in the limiting current, and the generation of H+ The large amount of OH- and OH- makes the regeneration effect of the anion and cation exchange resin filled in the shallow chamber good.
       2. The influence of working voltage-current.
       As the working current increases, the quality of the produced water continues to improve. However, if the current is increased after increasing to a high point, the amount of H+ and OH- ions produced by water ionization is too much. Except for the regeneration of resin, a large number of surplus ions act as current-carrying ions to conduct electricity. Accumulation and clogging occurs, and even reverse diffusion occurs, resulting in a decline in the quality of the produced water.
       3. The influence of turbidity and pollution index (SDI).
       The water production channel of the EDI module is filled with ion exchange resin. Excessive turbidity and pollution index will block the channel, causing the system to increase the pressure difference and decrease the water production.
       4. The influence of hardness.
       If the residual hardness of the influent water in the EDI is too high, it will cause the membrane surface of the concentrated water channel to scale, the concentrated water flow rate will decrease, and the product water resistivity will decrease; it will affect the quality of the product water, and will block the component concentrated water and extreme water flow channels in serious cases. The components are destroyed due to internal heat.
       5. The impact of TOC (total organic carbon).
       If the content of organic matter in the influent water is too high, it will cause organic pollution of the resin and the selective permeability membrane, which will cause the operating voltage of the system to rise and the quality of the produced water to decrease. At the same time, it is easy to form organic colloid in the concentrated water channel and block the channel.
       6. The influence of CO2 in water.
       HCO3- generated by CO2 in the influent water is a weak electrolyte, which easily penetrates the ion exchange resin layer and causes the quality of the produced water to decrease.
       7. The influence of total anion content (TEA).
       High TEA will reduce EDI product water resistivity, or need to increase EDI operating current, while too high operating current will cause the system current to increase, the concentration of residual chlorine in the extreme water increases, which is detrimental to the life of the electrode membrane. In addition, the inlet water temperature, pH value, SiO2 and oxides also affect the operation of the EDI system.
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