摘要
基于蓝铁石原位结晶磷回收技术,为更好地实现从污泥中分离和回收蓝铁石,需要深入研究蓝铁石结晶在污泥中的生长特性及活性污泥对结晶生长的影响.搭建厌氧反应装置,分别在有污泥和无污泥的反应装置中加入模拟生活污水和铁源,通过长期运行反应器,比较其蓝铁石结晶生长特性及差异.研究发现:厌氧污泥对蓝铁石结晶生长具有强化作用,且活性污泥系统和非污泥系统蓝铁石结晶的最终形态都是花型团聚体,活性污泥系统中的晶体更密集,更饱满;SI值为6左右时,晶体倾向于成核,SI值下降到3左右,晶体开始快速生长,在非污泥系统中前期需要更长的时间以达到成核所需的SI值.实验装置底部沉积物存在1～2 mm的蓝铁石晶体,可通过周期性重力分离回收蓝铁石结晶.
Abstract
In order to achieve better separation and recovery of vivianite from sludge,it is necessary to further study the growth Characteristics of vivianite crystals in sludge and the in fluence of activated sludge on crystal growth,an anaerobic reaction device was designed based on the phosphorus recovery technology of vivianite crystallization.Simulated domestic sewage and iron source were added to both the activated sludge system and the non-activated sludge system.The crystal growth characteristics and dif-ferences of vivianite were compared after the reactor operated for an extended period.The results showed that the anaerobic sludge could enhance the crystal growth of vivianite.The final morphology of vivianite crystals in both the activated sludge system and the non-sludge system was a flower-like aggregate,how-ever,the crystals in the activated sludge system were more dense and fuller.When the saturation index(SI)value was about 6,the crystals tended to nucleate.As the SI value dropped to around 3,the crystals began to grow rapidly.In the non-sludge system,the initial stage took more time to reach the SI value for nucleation.There were 1-2 mm vivianite crystals in the sediment at the bottom of the experimental de-vice.These vivianite crystals could be recovered by periodic gravity separation.
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