ENSAIT-IUT, University of Ngaoudere, P.O. Box 455, Cameroon.
University of Toulouse (Paul Sabatier), Geosciences Environment Toulouse, UMR CNRS-UPS 5563, 14 Av. Edouard Belin, 31400, Toulouse, France.
Water Res. 2016 Nov 15;105:361-369. doi: 10.1016/j.watres.2016.09.015. Epub 2016 Sep 12.
Ballasted aggregation, a process using the addition of a ballasting agent to improve the settling performance of flocs, appears particularly appropriate for the treatment of humic rich waters that leads to low-density aggregates. In that context, using an aquagenic humic acid coagulated by ferric chloride in the presence of pozzolana particles as ballasting agent, we show that the origin of improved floc settling in ballasted aggregation is not simply related to an increased specific weight of flocs, but also to a significant restructuring of flocs to a more compact structure induced by the added particles. The floc restructuring is evidenced from the increased lag time before measurable floc growth in the presence of the ballasting agent, the higher fractal dimension of flocs above the micron scale range after incorporation of the particles into the aggregates, and a much smaller sediment volume after settling. A simple model of floc compaction based on the turbulent viscous effects that act on an elastic floc, is described.
加重聚集，一种通过添加加重剂来改善絮体沉降性能的过程，对于处理富含有机物的水特别适用，因为这种水会导致低密度的絮体。在这种情况下，我们使用在水合腐殖酸存在下用三氯化铁凝结的自生腐殖酸作为加重剂，并证明了在加重聚集中改善絮体沉降的原因不仅仅与絮体的比重增加有关，而且还与由于添加的颗粒而引起的絮体的显著重构有关。絮体的重构可以从存在加重剂时可测量的絮体生长之前的滞后时间增加、颗粒加入絮体后微米级以上的絮体分形维数增加以及沉降后沉积物体积减小得到证明。描述了一个基于作用在弹性絮体上的紊流粘性效应的絮体压实简单模型。
