Integrated electrochemical processes for textile industry wastewater treatment: system performances and sludge settling characteristics

Hanane Afanga,Hicham Zazou,Youness Rakhila,Abdellah Elmchaouri,Rachid Ait Akbour,Mohamed Hamdani,Jaafar Ghanbaja,Fatima Ezzahra Titchou

doi:10.1186/s42834-019-0043-2

Hanane Afanga, Hicham Zazou + Show 6 more

Open Access

https://doi.org/10.1186/s42834-019-0043-2

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Abstract

Textile wastewater containing toxic dyes needs efficient treatment before being released into the environment. Certain dyes are known or presumed to have carcinogenic potential for humans. In this work, hybrid electrochemical processes including electrocoagulation (EC) alone and combined with electro Fenton (EF), anodic oxidation (AO) and peroxi-coagulation (PC) were tested to treat real textile wastewater using a batch reactor. A sequential EC and EF (EC-EF) process was found to be more effective. The experimental results indicated that the effectiveness of the treatment decreases in the following order: EC-EF > EC-AO > EC-PC > EC. EC-EF results showed a decrease in chemical oxygen demand (COD, 97%), total organic carbon (98%), total suspended solids (98%), and the concentration of metal species; showing that the treatment of such wastewater type can be achieved by combined EC-EF process in a one-pot bench-scale reactor. The electrical energy consumption, the iron dissolution, and the biological oxygen demand/COD ratios of EC and EC-EF processes were evaluated. Characterization of the sludge generated during EC treatment at current density of 20 mA cm− 2 was carried out. Precipitation, adsorption, and electrochemical oxidation/reduction of organic dyes and metallic ions occurred during the treatment. This investigation shows the efficiency of combined EC-EF to treat textile wastewater.

Highlights

The textile industry requires very large quantities of water during manufacturing and processing procedures, being major consumer of water [1]
The findings indicated that the effectiveness of the treatment decreases in the sequence EC-electro Fenton (EF) > ECAO > EC-PC > EC
The combination EC and EF (EC-EF) treatment leads to high color and total organic carbon (TOC) removal of real textile wastewater containing mainly methylene blue

Summary

Introduction

The textile industry requires very large quantities of water during manufacturing and processing procedures, being major consumer of water [1]. This industry uses about 10,000 different dyes, and more than 0.7 Mt of these dyes are annually produced worldwide [2]. Ten to fifteen percent of these dyes are released to the environment which constitutes one of the biggest environmental problems of the twenty-first century. These products cause serious damage to the environment due to the high concentration of color and dissolved matter in wastewater [3, 4].

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