Coprecipitation-Microfiltration Process For Treatment Of Wastewater Containing Cobalt And Strontium

Nuclear energy which promoted the economic development is widely applied inindustry, agriculture, medical, military and other fields in our country. At the sametime, the use of nuclear energy inevitably produces a large quantity of radioactivewastewater, which is harmful to the environment and human’s health,60Co and90Srare the typical radionuclides, they have long half-life, high toxicity and easilyaccumulate in the human body. Therefore, it is urgent to research on an appropriateprocess for the removal of60Co and90Sr.The paper investigated the treatment of wastewater containing cobalt andstrontium by coprecipitation-microfiltration combination process. The resultsindicated that the mean DF of cobalt and strontium was1692and587respectively,CF could reach1.02×103, the removal of cobalt and strontium was efficiency and thevolume of sediment yield was low. As a whole, the coprecipitation-microfiltrationprocess was feasible for the removal of cobalt and strontium from radioactivewastewaterThe difference of raw water in prilling process led to the difference of crystalparticles growth, which would affect the treatment effect. The study compared thedifference of crystal seed by different prilling raw water. The results showed that after30prilling cycles, the growth rate of the crystal seed was faster and the size of theseed was bigger by using strontium-containing water, the turbidity and hardness of theeffluent were low and stable; the growth rate of the crystal seed was irregular by usingcobalt-strontium mixed water, and the turbidity and hardness were far higher than theformer condition. After the treatment of cobalt-strontium mixed wastewater by thetwo batches of seed, the treatment effect was better by the stable crystal seed.Temperature was an important affecting fator of the process. So its effect on theprocess was studied. The results showed that the DF of cobalt and strontium wereimproved with the increasing of temperature, in9℃,15℃and26℃, the meanDF of strontium could reach320,488and587respectively; the mean DF of cobaltcould reach456,767and1692respectively. The CF under the three temperatureconditions could reach1.0×103. In a word, the rising of temperature was in favor ofcobalt and strontium removal, but the CF was affected a little.