Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, Droevendaalsesteeg 3a, 6708 PB Wageningen, The Netherlands.
Water Authority Brabantse Delta, Team Knowledge, P.O. Box 5520, 4801 DZ Breda, The Netherlands.
Toxins (Basel). 2020 Nov 5;12(11):700. doi: 10.3390/toxins12110700.
The combination of a low-dose coagulant (polyaluminium chloride-'Floc') and a ballast able to bind phosphate (lanthanum modified bentonite, LMB-'Sink/Lock') have been used successfully to manage cyanobacterial blooms and eutrophication. In a recent 'Floc and Lock' intervention in Lake de Kuil (the Netherlands), cyanobacterial chlorophyll- was reduced by 90% but, surprisingly, after one week elevated cyanobacterial concentrations were observed again that faded away during following weeks. Hence, to better understand why and how to avoid an increase in cyanobacterial concentration, experiments with collected cyanobacteria from Lakes De Kuil and Rauwbraken were performed. We showed that the from Lake de Kuil could initially be precipitated using a coagulant and ballast but, after one day, most of the filaments resurfaced again, even using a higher ballast dose. By contrast, the from Lake Rauwbraken remained precipitated after the Floc and Sink/Lock treatment. We highlight the need to test selected measures for each lake as the same technique with similar species () yielded different results. Moreover, we show that damaging the cells first with hydrogen peroxide before adding the coagulant and ballast (a 'Kill, Floc and Lock/Sink' approach) could be promising to keep precipitated.
低剂量混凝剂（聚合氯化铝 - "Floc"）和能够结合磷酸盐的压载物（镧改性膨润土，LMB-"Sink/Lock"）的组合已成功用于管理蓝藻水华和富营养化。在最近对荷兰 Kuil 湖的 "Floc 和 Lock" 干预中，蓝藻叶绿素减少了 90%，但令人惊讶的是，一周后再次观察到蓝藻浓度升高，随后几周逐渐消失。因此，为了更好地理解为什么以及如何避免蓝藻浓度增加，对从 Kuil 湖和 Rauwbraken 湖收集的蓝藻进行了实验。我们表明，来自 Kuil 湖的蓝藻最初可以用混凝剂和压载物沉淀，但一天后，即使使用更高的压载剂量，大部分丝状蓝藻又重新浮出水面。相比之下，来自 Rauwbraken 湖的蓝藻在 Floc 和 Sink/Lock 处理后仍然沉淀。我们强调需要对每个湖泊进行选定措施的测试，因为相同的技术对类似物种（）产生了不同的结果。此外，我们表明，在用混凝剂和压载物之前先用过氧化氢破坏细胞（"Kill, Floc 和 Lock/Sink" 方法）可能有助于保持蓝藻沉淀。
