First Application of Natural Polymer to the Direct Filtration System: Moringa Oleifera

摘要

Recent years, it has been found that Moringa oleifera is the best organic natural polymer discovered yet, which is active and safe for human health. The focus of this research has been the application of the natural polymer to the direct filtration system. The experimental work has been conducted in both laboratory and pilot scale employing natural turbid water. During the laboratory tests, jar test has been applied to compare between natural polymer and aluminum sulphate as a common coagulant in developing countries. The turbidity of the natural water samples were ranged from 7.60 to 23 NTU. Polymer dose of 1, 2 and 3 mg/l have been tested as well as alum dose of 5, 15 and 20 mg/l. After mixing and settling the jars, the best polymer dose was found to be 3 mg/l producing turbidity of 1.60 NTU while the best alum dose was 20 mg/l producing turbidity of 1.08 NTU. Noteworthy, it has observed that the sludge produced from the natural polymer is one fifth the sludge produced from the alum. A direct filtration pilot plant has been constructed to treat 3.0 m3/d of natural surface water as an average flow. The pilot plant consisted of rapid mixing tank, dosing system and 200 mm filtration column using coarse sand media. Results obtained from several runs showed that the naturally derived polymer has resulted in increasing the rate of filtration to 4.50 m/hr instead of 3.25 m/hr compared to the alum case. as well as increasing the run length up to 150%. Moreover, the effluent turbidity ranged from 0.76 to 1.03 NTU while the influent turbidity ranged from 17.70 to 23 NTU and the algal removal efficiencies ranged from 90 to 96% without chlorination. Thus constituting a high potential of using the Moringa Oleifera as a natural coagulant alternative to the alum and other metallic salts, especially in developing countries.