PhD. María Irene Kopytko 1, Ing. Eliana Paola Rueda Villamizar 2, Ing.Yuliana Rincón Picón 3.
1 Environmental Engineering Department, Faculty of Engineering, Pontificia Bolivariana University, Bucaramanga, Colombia. 2 Pontificia Bolivariana University, 3 Pontificia Bolivariana University, Bucaramanga, Colombia.

Abstract

The natural substance and alum were tested in the process of water treatability at Palmichada stream (Colombia), where Aloe Vera showed good performance in every assay due to the great versatility of its composition, which aids in the coagulation as well as in the flocculation process. Regardless of the turbidity of the water sample analyzed, the Aloe Vera solution proved to be a poor primary coagulant.The solution of Aloe Vera as coagulation aid achieved a decrease up to 20% of the optimal dose of aluminum sulfate in water samples in medium turbidity and up to 40% of the optimal dose of alum in high turbidity samples at Palmichala stream,andexceeding 95% turbidity removal. In the same way, when applied as a flocculation aid in conjunction with alum, the blend caused a reduction of 20% in the optimal dose of alum and removed turbidity up to 96% from the raw water. Introducing the Aloe Vera solution in coagulation – flocculation procedures avoids the generation of any non-treatable wastes or changes in the natural taste of water. These processes are easy to operate and require minimum maintenance. Design and operation parameters were calculated for small plants in rural areas when applying the experimental results from this study. Raw water with medium-level turbidity (45,5 NTU) required 56mg/l of alum with 5mg/l of Aloe Vera blend as a coagulation aid while water with a high-level turbidity (101 NTU) required 24mg/l of alum with 14mg/l of Aloe Vera blend as a coagulation aid in order to achieve more than 90% turbidity removal.

I. INTRODUCTION

Water is a vital resource, but presents a worrisome depletion in recent times. Adequate water supply for human consumption is a concern, since most of this resource is found in oceans where the high salt content makes it unsuitable for drinking. Features such as growing population, increased economic activities and industrialization have resulted in high demand for drinking water and the subsequent misuse of this natural resource, which is severe. This hinders the treatability process and increases water treatment costs. For these reasons, coagulation - flocculation procedures associated with other processes are of great importance in order to separate contaminating components and achieving high degrees of drinking water quality.

Aluminum sulfate (alum) has been the chemical coagulant used for drinking water treatments due to the low costs, attainability and comfortable handling. However, continuous use of alum has caused several problems affecting human health. Studies have shown that aluminum is one of the causes for Alzheimer's syndrome [1]. In addition, aluminum sulphate generates inconveniences because of the large amounts of sediments, which may be regarded as highly hazardous waste [2],[3],[4]. Another adverse characteristic of aluminum sulfate is the permanence in the drinking waterlife-cycle that are present in natural water resources, animals, people and plants [5].Owing to various problems generated by the use of alum, new alternatives for drinking water treatments should be studied. [6],[7].

Colombia holds diverse natural resources, which are able to offer various alternative methods to treat water.This study aims to promote the use of natural substances in drinking water treatments through easy applicable methods suitable for small populations that require them. [8]In the past two decades, an innovative drinking water treatment strategy using natural coagulants has shown high reliability for coagulation - flocculation techniques achieving high efficiency in turbidity removal and color while providing additional advantages such as low cost and manageability, e.g. Okra gum, dry flowers of Calotropis Procera, few plant seeds of the species Loganiaceae-Strychnos potatorum and Moringaceae-Moringa Olifera and Moringa stenopetala have been used to clarify turbid water. [9], [10], [11], [12].