Trihalomethanes minimization in drinking water by coagulation/flocculation/sedimentation with natural coagulant Moringa oleifera Lam and activated carbon filtration

Water treatment plants are designed to remove turbidity and apparent colour, and produce safe water from a microbiological and chemical point of view. Disinfection is the step responsible for the microbiological security, for which chlorine is the most widely‐used agent, since it can react with orga...

Full description

Saved in:
Bibliographic Details
Published in:Canadian journal of chemical engineering 2016-07, Vol.94 (7), p.1277-1284
Main Authors: dos Santos, Tássia Rhuna Tonial, Bongiovani, Milene Carvalho, Silva, Marcela Fernandes, Nishi, Letícia, Coldebella, Priscila Ferri, Vieira, Marcelo Fernandes, Bergamasco, Rosângela
Format: Article
Language:English
Subjects:
Activated carbon
Coagulants
coagulation/flocculation/sedimentation
Color
Colour
Filtration
Hexanes
Moringa oleifera Lam
Sedimentation
trihalomethanes
Turbidity
water treatment
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Water treatment plants are designed to remove turbidity and apparent colour, and produce safe water from a microbiological and chemical point of view. Disinfection is the step responsible for the microbiological security, for which chlorine is the most widely‐used agent, since it can react with organic matter present in raw water to form total trihalomethanes (TTHM), which are harmful to humans. In this context, it is proposed to evaluate the effectiveness of the combined process of coagulation, flocculation, and sedimentation (C/F/S) followed by an activated carbon column. The water for the tests was from the Pirapó River (Brazil) with low colour and turbidity. In C/F/S tests, natural coagulant solutions from Moringa oleifera (MO) degreased with ethanol (MO(et)) and hexane (MO(hex)) were compared to coagulant aluminum polychloride (PAC) with further filtration in an activated carbon column. For all these tests, removal efficiency of apparent colour, turbidity, dissolved organic carbon (DOC), and compounds with UV254nm absorption (UV254nm) were evaluated. The disinfection process was performed and residual chlorine and TTHM formation were evaluated. It was observed that the process of C/F/S using MO(et) followed by filtration through activated carbon was able to reduce the values ​​of physicochemical parameters (96 % removal for turbidity and apparent colour, 93 % for UV254nm, and 99 % for DOC) with reduced formation of TTHM (25.31 μg/L). Moreover, oil extraction with ethanol presents advantages over hexane due to being a solvent with good operational security, low toxicity, and being a bio‐renewable source, all characteristics not present in hexane.
ISSN:0008-4034
1939-019X
DOI:10.1002/cjce.22506