Investigating the Coagulating Potential of Cactus Mucilage Powder for Surface Water Treatment (Case of Legedadi reservoir)
Creators: name: Tsion Eticha Urgessa
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2020
Subjects: Opunta Ficus Indica, surface water, optimization, Response surface methodology.

description: The method mostly effective and simple to apply for the removal of colloidal and suspended solid<br> contaminants from surface water which technically need adding either chemical or natural<br> coagulant is called a process of coagulation. However, the use of chemical coagulants have been<br> criticized, because of certain constraints, such as concern for human health, costs of chemicals<br> and the problem of sludge management (particularly in developing countries). The goal of this<br> study is to explore the coagulating ability of cactus mucilage powder (Opuntia Ficus Indica) for<br> surface water treatment as an alternative and the optimization of coagulation activity in order to<br> eliminate turbidity from the source of surface water using Design Expert® software. The OFI<br> mucilage powder was characterized using physico-chemical properties according to standard<br> procedure the results were: moisture content 12.58 %, bulk density 0.67 g/cm3, ash value 33.30<br> %, viscosity 15.00 mPas, pH 5.21 and conductivity 17.03 mS/cm. These physico-chemical<br> properties of the mucilage can be an indication on their potential use as a coagulant. Functional<br> group and surface morphology identification study also confirmed the presence of various<br> functional groups which are responsible for the coagulation process.<br> The initial surface water characteristic of some parameters measured before jar test are:<br> Temperature 20.25 0C, pH 6.66, EC 106.68 μS/cm, Turbidity 230.25 NTU, TSS 67.32 mg/L, TDS<br> 51.75 mg/L, TS 119.07 mg/L, 21,000 and 14,000 for total and fecal coliform per 100ml sample<br> respectively. This shows that the raw surface water was highly turbid, has low mineral content,<br> slightly acidic in pH and high health risk. Treated water using OFI powder was increased in TDS<br> and EC. The experiment was carried out using a jar test apparatus: coagulant dose, pH and slow<br> mixing time were the three factors considered on the turbidity removal efficiency optimized using<br> Design Expert® software of response surface methodology (RSM) Based on the design a quadratic model was developed to correlate the parameter variables to the<br> turbidity removal percentage. Furthermore, the analysis of variance (ANOVA) was used to check<br> the significance of the model and obtained coefficient of determination (R2) 0.98 for turbidity<br> removal. Optimum coagulation was at coagulant dose of 238.00 mg/L, pH 7.10, &amp; slow mixing<br> time of 29.00 minutes at these optimal conditions the removal efficiency of turbidity was 97.83%<br> and the sludge volume was reduced from 5.00% to 3.50%. Therefore, RSM can be used to optimize<br> the coagulation of surface water using OFI plant. Hence, it can be concluded that mucilage of OFI<br> can be used as coagulant to remove turbidity of surface water sources.<br>