The combination of a low dose of coagulant with a ballast that can inactive phosphorus (P) in lake sediment—a technique known as “flock and lock”—is one method for restoration of eutrophic lakes. The effectiveness of a drinking water treatment residual (DWTR) as a ballast in flock and lock was assessed using assays of eutrophic lake water from Thailand dominated by Microcystis aeruginosa cyanobacteria colonies by measuring changes in chlorophyll-a, pH, and zeta potential. P sorption isotherms were developed from long-term batch equilibrium experiments; desorption of nutrients and metals was assessed via leaching experiments; and morphological changes to cellular structure were assessed using scanning electron microscopy. Results showed that combining DWTR with a low dose of aluminum sulfate (0.6-4.0 mg Al/L) effectively sank 74-96% of Microcystis, with DWTR dose (50-400 mg/L), initial chlorophyll-a concentration (92-976 µg/L), pH (7.4-9.3), and alkalinity (99-108 ppm CaCO₃) identified as factors significantly associated with sinking efficacy. P sorption capacity of the DWTR (7.12 mg/g) was significantly higher than a local soil (0.33 mg/g), enabling the DWTR to inactivate P in lake sediment. Desorption of Al, Fe, Ca and N from the DWTR was estimated to contribute to a marginal increase in concentrations of those compounds in the water column of a small shallow lake (1.2, 0.66, 53.4, and 0.07 µg/L, respectively) following a simulated application. Therefore, pre-treated DWTRs may be a viable alternative ballast in the flock and lock approach to lake restoration, supplementing or replacing modified local soils or lanthanum modified clays.

将低剂量混凝剂与可以使湖泊沉积物中的磷 (P) 失活的压载物相结合——这种技术被称为“flock and lock”——是恢复富营养化湖泊的一种方法。使用以铜绿微囊藻为主的泰国富营养化湖水的测定，评估了饮用水处理残留物 (DWTR) 作为畜群和船闸压舱物的有效性通过测量叶绿素 a、pH 和 zeta 电位的变化来观察蓝藻菌落。P 吸附等温线是从长期批次平衡实验中得出的；通过浸出实验评估营养物和金属的解吸；使用扫描电子显微镜评估细胞结构的形态变化。结果表明，DWTR 与低剂量硫酸铝 (0.6-4.0 mg Al/L) 相结合，可有效地沉没 74-96% 的微囊藻，DWTR 剂量 (50-400 mg/L)，初始叶绿素-a浓度 (92- 976 µg/L)、pH (7.4-9.3) 和碱度 (99-108 ppm CaCO ₃) 被确定为与下沉效率显着相关的因素。DWTR 的 P 吸附能力 (7.12 mg/g) 显着高于当地土壤 (0.33 mg/g)，使 DWTR 能够灭活湖泊沉积物中的 P。据估计，从 DWTR 中解吸 Al、Fe、Ca 和 N 会导致这些化合物在小型浅湖水柱中的浓度略有增加（分别为 1.2、0.66、53.4 和 0.07 µg/L），如下所示：一个模拟的应用程序。因此，预处理的 DWTR 可能是一种可行的替代压载物，用于湖泊修复、补充或替代改良的当地土壤或镧改良粘土的羊群和锁闭方法。