温度和初始颗粒大小对絮体破碎再絮凝的研究

Infuence of temperature and the size of initial particles on flocs breakage and re-growth

鉴于絮体的形成/破碎/再絮凝过程在适当条件下具有强化去除水中颗粒物的效果,研究温度和初始颗粒大小对絮体破碎再絮凝去除水中颗粒的影响.采用PDA2000透光率脉动检测仪对絮体破碎再絮凝过程进行在线监测.结果表明,在较低温度条件下,絮体破碎后能有较大的恢复率;初始颗粒越大,絮体大小恢复率越高,由较小初始颗粒产生的絮体经破碎后再絮凝其再生能力不如大颗粒,沉后水浊度与大颗粒相比不具有降低优势.当电中和机理占主导作用时,絮体破碎后能重新絮凝,絮体大小能恢复到破碎之前;而当网捕卷扫机理占主导作用时,絮体的恢复能力不如电中和条件,再絮凝能力降低.絮体破碎后再絮凝的沉后水浊度明显低于破碎前,水温对其结果的影响不大.絮体破碎后再絮凝,适用于较大的初始颗粒和较低水温.

This paper investigated the effect of temperature and the size of original particles on the flocs regrowth capability and the particles removal by flocs breakage and re-growth. The process of formation, breakage, and re-growth of flocs was investigated with PDA 2000. It is found that there is a full re-growth of broken floes when coagulating in charge neutrality, while coagulating in sweep coagulation, the break-up process of flocs displays distinct irreversibility. The lower temperature results in the higher re-growth capability of broken floes, and the reversibility of broken floes formed by small particles is lower than that formed by big particles. The residual turbidity after re-growth of broken flocs is significantly lower than that before flocs breakage, which was little influenced by temperature. The size of original particles has positive effect on the discrepancy of residual turbidity before and after breakage. The technology can be used for the surface water with big particles and low temperature.