Pilot-Scale Electrochemical Treatment of Textile Effluent and its Toxicological Assessment for Tilapia (Oreochromis niloticus L.) Culture

Textile industries have as main characteristic the generation of effluents with high color, and efficient treatment techniques are necessary. In this context, this study compared the efficiency of the electrochemical treatment for color removal from synthetic textile effluent using two configurations of sacrificial electrodes, parallel plates and array of cylindrical electrodes. For application of the electroflocculation technique, an electrochemical reactor was used, in a laboratory scale, operated in a continuous flow. The synthetic textile effluent was prepared with preset concentrations of reactive dye Blue 5G and sodium chloride. Sacrificial iron (Fe) electrodes with different configurations were used: parallel plates and cylindrical electrodes. The Hydraulic Retention Time (HRT) and electric current density (j) were controlled, and their effects on color removal were evaluated using a Central Composite Rotational Design (CCRD) composed of 12 trials. For the electrochemical treatment using parallel plates, the color removal efficiency ranged from 56.13% to 98.95% and for the electrochemical treatment using an array of cylindrical electrode, the color removal efficiency varied from 2.11% to 97.84%. The mathematical models representative of the process explained a high proportion of the total data variability, with a coefficient of variation of 99.49% and 97.21% for parallel plates and arrangement of cylindrical electrodes, respectively. The electrochemical treatment using parallel plates presents advantages over the configuration using a cylindrical electrode array, since the color removal efficiency is superior under the same operating conditions, representing economic and environmental gains.

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Toxicity Evaluation of Wastewater Treatment Plant of Textile Effluent Using Fish: Nile tilapia Oreochromis niloticus

International Journal of Aquaculture ◽

10.5376/ija.2013.03.0010 ◽

2013 ◽

Author(s):

Workagegn Kassaye Balkew

Keyword(s):

Wastewater Treatment ◽

Wastewater Treatment Plant ◽

Oreochromis Niloticus ◽

Nile Tilapia ◽

Treatment Plant ◽

Textile Effluent ◽

Toxicity Evaluation

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Pilot-scale electrochemical disinfection of surface water: assessing disinfection by-product and free chlorine formation

Water Science & Technology Water Supply ◽

10.2166/ws.2016.165 ◽

2016 ◽

Vol 17 (2) ◽

pp. 526-536 ◽

Cited By ~ 7

Author(s):

Charles E. Schaefer ◽

Graig M. Lavorgna ◽

Todd S. Webster ◽

Marc A. Deshusses ◽

Christina Andaya ◽

...

Keyword(s):

Surface Water ◽

Energy Demand ◽

Heterotrophic Bacteria ◽

Pilot Scale ◽

Electrochemical Treatment ◽

Mixed Metal Oxide ◽

Electrochemical Disinfection ◽

Subsequent Exposure ◽

Low Levels ◽

Chlorine Generation

Electrochemical disinfection of surface water using mixed metal oxide anodes was evaluated in a pilot-scale demonstration. Disinfection rates, chlorine generation, energy demand, and generation of disinfection by-products were monitored over the 190-day study. Particular attention was given to the generation of trihalomethanes (THMs) and haloacetic acids (HAAs) during the electrochemical treatment cycle. In addition, the potential for generation of THMs and HAAs during post-treatment storage of the water was assessed. The electrochemical treatment system resulted in a 2- to 3-log removal of total heterotrophic bacteria, with values below detection (<1 CFU/mL) often observed. Disinfection occurred with only very low levels of observed chlorine generation (<0.1 mg/L), suggesting that alternate disinfection mechanisms likely played a significant role in the observed removal of bacteria. THM and HAA concentrations after treatment were consistently well below regulatory levels. Results also showed that electrochemical treatment significantly reduced the formation of bromoform when the water received subsequent exposure to hypochlorite. Removal of naturally occurring bromide in the water by the electrochemical system may have been the cause (in part) for this observed mitigation of bromoform formation. The formation of calcium scale on the cathode surface over time was the primary operational challenge.

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Biological denitrification of a textile effluent in a dynamic sand filter

Water Science & Technology ◽

10.2166/wst.1998.0031 ◽

1998 ◽

Vol 38 (1) ◽

pp. 123-132 ◽

Cited By ~ 4

Author(s):

R. Canziani ◽

L. Bonomo

Keyword(s):

Removal Rate ◽

Plug Flow ◽

Pilot Scale ◽

Zero Order ◽

Biofilm Reactor ◽

Textile Effluent ◽

Order Kinetic ◽

Sand Filter ◽

Loading Rates ◽

Nitrogen Bubbles

Post-denitrification of a pre-treated textile effluent was tested in a pilot-scale dynamic up-flow sand filter, which has been used as a biofilm reactor, together with filtration of suspended solids (SS) and decolorization. The potential application of the reactor as a three-in-one unit (decolorization, filtration and denitrification) has been successfully tested. Biomass growth and the sloughing of biological film did not prevent the removal of high concentrations of influent SS. Both pilot- and bench-scale tests confirmed that the intrinsic denitrification kinetics was zero-order, corresponding to a half-order removal rate if nitrate concentration is lower than 10 mgN l−1. Zero-order and half-order kinetic constants have also been calculated. At low nitrate loading rates (up to 2 kgN m−3 d−1) the filter followed the ideal plug-flow hydrodynamic model. In the lower part of the filter, zero-order kinetics fitted denitrification removal rates, while in the upper part of the filter denitrification followed half-order kinetics. At nitrate loading rates higher than 2.5 kgN m−3 d−1, nitrogen bubbles developed and partially mixed the reactor. Consequently, flatter concentration profiles were detected in the reactor and denitrification followed half-order kinetics along the entire filter.

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