ABSTRACT

In this study, a multivariate $2^3$ experimental design was applied to optimize the operational conditions (seed mass, salt concentration, and pH) to employ Ceratonia siliqua L. (carob) and Moringa oleifera Lam (moringa) as coagulating/flocculating agents for water treatment. Currently, the coagulation stage in water treatment uses aluminium compounds, due to the characteristic reaction to natural alkalinity in raw water, and for its low market value. Considering that aluminium effects on human health are not sufficiently studied to acknowledge its toxicity, and its significant environmental impacts, it is suitable for the studies to search for alternatives to be employed in the water treatment that will be distributed to human consumption. This study was carried out with raw water of high turbidity level, 83.7 NTU. The raw water collected was also characterized according to pH, colour, Total Organic Carbon (TOC), Dissolved Organic Carbon (DOC), and Dissolved Organic Matter (DOM), with values of 6.7, 178 NTU, 6.80, 2.45 and 138.58 mg/L, respectively. The optimized results showed that with 2 g of seed, 0.5 mol ${\mathrm{L}}^{-1}$ of NaCl, and pH 11.0 In these conditions, moringa coagulant reached 90%, 86%, 6%, 67%, and 81% for turbidity, colour, DOC, TOC, and DOM removal, respectively, whereas the carob coagulant achieved 85%, 76%, 5%, 55.6%, 66.7%, respectively for the same parameters’ removal. Both coagulants presented lower sludge formation, 1.1 mL L⁻¹ for moringa coagulant, and 1.1 mL L⁻¹ for carob coagulant. The results could be considered promises, and natural polymers carob and moringa can be suggested as alternatives agents in coagulation/flocculation stages for water treatment.

摘要

在本研究中，多变量$2^3$应用实验设计来优化操作条件（种子质量、盐浓度和 pH 值）以使用Ceratonia siliqua L.（角豆）和辣木Lam（辣木）作为水处理的凝结剂/絮凝剂。目前，水处理中的混凝阶段使用铝化合物，这是由于其对原水的天然碱性反应的特性，以及其较低的市场价值。考虑到铝对人类健康的影响尚未得到充分研究以承认其毒性及其对环境的重大影响，因此研究适合寻找可用于水处理的替代品，这些替代品将分发给人类消费。本研究使用高浊度 83.7 NTU 的原水进行。收集的原水还根据 pH 值、颜色、总有机碳 (TOC)、溶解有机碳 (DOC) 和溶解有机物 (DOM) 进行表征，值为 6.7、178 NTU、6.80、2.45 和 138.58 mg/ L，分别。${\mathrm{大号}}^{-1}$NaCl 和 pH 11.0 在这些条件下，辣木混凝剂的浊度、颜色、DOC、TOC 和 DOM 去除率分别达到 90%、86%、6%、67% 和 81%，而角豆树混凝剂达到 85% , 76%, 5%, 55.6%, 66.7%，分别为相同参数的去除。两种混凝剂均呈现较低的污泥形成，辣木混凝剂为 1.1 mL L ^{-1 ，角豆树混凝剂为 1.1 mL L -1}。结果可以被认为是有希望的，并且可以建议天然聚合物角豆和辣木作为水处理混凝/絮凝阶段的替代剂。