Federal University of Ceará, Department of Hydraulic and Environmental Engineering, Block 713, Campus Pici, Fortaleza, Ceará, Brazil.
Federal University of Rio Grande do Norte, Postgraduate Program in Civil and Environmental Engineering, Natal, Brazil.
Sci Total Environ. 2024 Aug 20;939:173378. doi: 10.1016/j.scitotenv.2024.173378. Epub 2024 May 24.
Cyanobacterial blooms have been a growing problem in water bodies and attracted attention from researcher and water companies worldwide. Different treatment methods have been researched and applied either inside water treatment plants or directly into reservoirs. We tested a combination of coagulants, polyaluminium chloride (PAC) and iron(III) chloride (FeCl), and ballasts, luvisol (LUV) and planosol (PLAN), known as the 'Floc and Sink' technique, to remove positively buoyant cyanobacteria from a tropical reservoir water. Response Surface Methodology (RSM) based on Central Composite Design (CCD) was used to optimize the two reaction variables - coagulant dosage (x) and ballast dosage (x) to remove the response variables: chlorophyll-a, turbidity, true color, and organic matter. Results showed that the combination of LUV with PAC effectively reduced the concentration of the response variables, while PLAN was ineffective in removing cyanobacteria when combined to PAC or FeCl. Furthermore, FeCl presented poorer floc formation and lower removal efficiency compared to PAC. This study may contribute to the theoretical and practical knowledge of the algal biomass removal for mitigating eutrophication trough different dosages of coagulants and ballasts.
蓝藻水华已成为水体中的一个日益严重的问题，引起了全球研究人员和水务公司的关注。已经研究和应用了不同的处理方法，无论是在水处理厂内部还是直接在水库中。我们测试了一种组合混凝剂，聚氯化铝（PAC）和氯化铁（FeCl）和压载物，淋溶土（LUV）和雏形土（PLAN），称为“絮凝和下沉”技术，以去除热带水库水中的正浮力蓝藻。基于中心组合设计（CCD）的响应面法（RSM）用于优化两个反应变量 - 混凝剂剂量（x）和压载物剂量（x），以去除响应变量：叶绿素-a、浊度、真色和有机物。结果表明，LUV 与 PAC 的组合有效地降低了响应变量的浓度，而 PLAN 与 PAC 或 FeCl 结合时对去除蓝藻无效。此外，与 PAC 相比，FeCl 的絮体形成较差，去除效率较低。本研究可能有助于通过不同剂量的混凝剂和压载物去除藻类生物量以减轻富营养化的理论和实践知识。
