Cactus has shown great capabilities as a bio coagulant/flocculent in the treatment of wastewater and as a factor for sustainable development of the environment, due to its abundance and non-toxicity for human health. This has encouraged the present study based on the design of experiments to optimize the two operating factors: the bio coagulant dosage and initial pH. The effect of these considered factors on turbidity and chemical oxygen demand (COD) reduction performances was investigated to treat sewage wastewater from plants by the coagulation/flocculation process using the response surface methodology (RSM) based on a central composite faced design (CCFD). The effect of the pH on the supernatant turbidity removal and the COD reduction was very significant whereas that of the coagulant dosage was insignificant on the COD removal efficiency. Experimental results revealed that the maximum reduction of turbidity and COD could be reached at a coagulant dosage of 28 mg/l and a pH of 12. At these optimal conditions, the removal efficiency of turbidity and COD was 98.33% and 96.55% respectively. By the end of the treatment, final values of 0.84 NTU and 20.8 mg/l were obtained for turbidity and COD, respectively. A notable decrease of orthophosphate (O- PO4−2), nitrite (N-NO3−), ammonium (N-NH4+) and suspended matter (SM) was observed. The study also showed that the quadratic regression model could be used as a theoretical basis for the process based on a high coefficient of determination R2 value > 0.96, obtained from the analysis of variances (ANOVA).

中文翻译：

---

响应面方法在生物混凝过程（污水废水处理厂）的建模和优化中的应用

由于仙人掌丰富且对人类健康无毒，仙人掌在废水处理中作为生物混凝剂/絮凝剂显示出强大的能力，并作为环境可持续发展的一个因素。这鼓励了基于实验设计的本研究来优化两个操作因素：生物混凝剂剂量和初始 pH 值。研究了这些考虑因素对浊度和化学需氧量 (COD) 降低性能的影响，以使用基于中心复合面设计 (CCFD) 的响应面方法 (RSM) 通过混凝/絮凝过程处理来自植物的污水。pH值对上清液浊度去除和COD降低的影响非常显着，而混凝剂用量对COD去除效率的影响不显着。实验结果表明，混凝剂用量为28 mg/l，pH值为12时，浊度和COD的降低幅度最大。在这些最佳条件下，浊度和COD的去除效率分别为98.33%和96.55%。到处理结束时，浊度和 COD 的最终值分别为 0.84 NTU 和 20.8 mg/l。观察到正磷酸盐 (O-PO4-2)、亚硝酸盐 (N-NO3-)、铵 (N-NH4+) 和悬浮物 (SM) 的显着减少。该研究还表明，基于从方差分析 (ANOVA) 获得的高决定系数 R2 值 > 0.96，二次回归模型可用作该过程的理论基础。