An agricultural waste as a novel coagulant aid to treat high turbid water containing humic acids

Abstract

Production of potable water from most raw water sources usually uses the coagulation/flocculation process to remove turbidity. Alum is widely used as a coagulant. However, there is concern about its associated risk of Alzheimer disease. As a result, there has been considerable interest in the development of natural coagulants and coagulant aids in order to reduce the dose of alum. This study aimed to evaluate the use of the Corchorus Olitorius L. (COL), a leaf vegetable grown in Africa and the Middle East, as a novel coagulant aid. COL has important advantages over other coagulant aids. It is an agricultural waste that is widely produced and does not require further chemical treatment. Tests were carried out to evaluate the optimal dosages and conditions required to achieve optimum removal of both turbidity and humic acid. Based on the results of jar test, COL is an efficient coagulation aid. It has the ability to reduce both the primary coagulant dose from 600 mg l -1 to 300 mg l -1 and the residual turbidity from 5.63 to 0.26 NTU. This novel coagulant aid also reduced the total organic carbon (TOC) concentration to zero level. It also increased the rate of flocculation.