Pilot scale treatment of textile wastewater by combined process (fluidized biofilm process–chemical coagulation–electrochemical oxidation) (original) (raw)
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Treatment of text wastewaters from a large dyeing and finishing mill by a continuous process of combined chemical coagulation, electrochemical oxidation and activated sludge treatment is investigated. The experimental results are assessed in terms of COD and color (turbidity) reductions to determine the overall treatment efficiency of the combined process. Operating variables, such as the wastewater flow rate, conductivity, pH, applied current and amount of polyaluminum chloride (PAC), are explored to determine their respective effects on the efficiency of the electrochemical oxidation of the textile wastewater. Optimum operating range for each of those operating variables are experimentally obtained. Economic evaluation of the combined treatment method indicates that it is highly competitive in comparison to the conventional treatment method practiced in the textile industry.
Treatment of Textile Wastewater by Electro-coagulation and Activated Sludge Process
In the present study, removal characteristics of Cu (II) ion from waste water using fly ash – a low cost adsorbent has been studied. Environment friendly wastewater treatment method is the biggest challenge faced by textile industries. Water system around Dhaka City Corporation experiences high concentration of COD and color in the discharge effluent into environment by textile industries. Lack of appropriate treatment facility for wastewater exceeds the standard discharge limits. Conventional wastewater treatment methods become decisive challenge to environmental engineers for increasing more and more restrictive effluent by water and industrial discharges. Biologically treated discharges will no longer be reduced textiles dyes or color as 53% of 87 colors are identified as non-biodegradable. On the other hand, electro-coagulation or coagulation method produces a huge amount of hydroxide sludge that is harmful for our environment. The purpose of this study is to investigate a single treatment method that is properly and effectively treated different types of textile effluent. Electro-coagulation method for treatment of textile effluent and reduction of COD, BOD and color from effluent is compared with activated sludge process. The chemical and biological oxidation is carried out using electro-coagulation and bacillus bacteria respectively without adjustment pH of the wastewater sample. In this work, the comparison of the efficiency of electro-coagulation and activated sludge process for COD, BOD and color removal of different textile industries in Bangladesh are investigated. Electro-coagulation or coagulation method and activated sludge process results are not satisfied to protect our ecology and human health, so combined method of wastewater treatment is necessary. From cost estimation and practical performance of different treatment methods textile wastewater revealed high susceptibility to treat the effluents using electro-coagulation and biological method separately. Effluent characteristics such as color and chemical oxygen demand (COD) are reduced by considerable amount by electro-coagulation method but in activated sludge process marked degradation of pollutants than coagulation method. If we combined at first electro-coagulation then activated sludge process, a better result will be found that is more effective and economical than any single method because non-biodegradable organic matters are not destroyed by activated sludge process, so combination of methods is necessary.
Treatment of Textile Wastewater by Electrochemical Method
In this study, the textile dying effluent treatment by electrochemical oxidation technique is optimized experimentally. It was identified that copper and stainless steel were the best anode and cathode materials respectively. The operational parameters such as supporting electrolyte (sodium chloride) concentration, initial pH and electrolysis time on pH changes and percentage of color, Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), Total Organic Carbon (TOC) were determined. The optimum range for each of these operating variables was experimentally investigated. The results show that the percentage of color, COD, BOD, TOC are removed effectively in the aqueous solution. The optimum conditions identified for electrochemical oxidation technique are 0.1M Nacl concentration, 7.67 pH and 105 minutes electrolysis time. Under these conditions the percentage of color and COD removal efficiencies were reached 96.2, while for BOD and TOC removals the percentage is slightly lower.
Innovative Electrochemical treatment of textile dye wastewater
Egyptian Journal of Chemistry
A PPLICATION of electrocoagulation (EC) for removal of Chemical Oxygen Demand (COD) and color from textile wastewater is the aim of this research. Batch wise experiments were carried out using iron electrodes to investigate effect of pH, current density and electrolysis time on percentage removals. Results show maximum removal efficiency of COD (65%) and color (97%) at 0.9 A and 0.4 A, respectively at 1.6 V and 120 minutes reaction time. Moreover, the results show that the COD removal is influenced by the pH with maximum removal at pH 8. The EC process improves wastewater biodegradability with increasing BOD/ COD ratio from 29% to 34%. The results prove that the EC is effective in color and COD removal. Regarding electrical current, there was no significant difference between 0.5 A and 0.7A in color removal and so 0.5 A is selected as cost effective for the treatment process with estimated Electricity Consumption of 3.2 kWh/m 3. Impact of treated wastewater on oxygen uptake rate of activated sludge biomass was investigated and the results indicated that both dye and minerals content have negative impact and therefore it is recommended to reuse treated effluent in industrial processes or consider total dissolved solids in the effluent disposal limits.
Alexandria Engineering Journal, 2014
Toxic organic dye removal from the textile wastewater is a serious concern. It is difficult to choose a single or a combination of treatment techniques between various available options; each with certain advantages and drawbacks. Six different techniques were applied on the same textile wastewater to evaluate the most effective in terms of treatment efficiency. The three most important textile wastewater quality parameters of chemical oxygen demand (COD), total suspended solids (TSS) and color were made the basis of the comparison of different treatment techniques. Other critical parameters such as treatment time, ease of operation and chemical cost employed were also considered. No single biological or physico-chemical treatment technique was found capable of removing up to 80% of the influent COD, TSS and color simultaneously from the textile wastewater. The conventional activated sludge (CAS) treatment followed by effluent polishing with the sand filtration (SF) and activated carbon adsorption columns was proved to be the most promising with COD, TSS and color removal efficiencies of 81.6%, 88.5% and 94.5% respectively. Moreover this combination of techniques enjoys lower chemical cost, medium operation time and fewer difficulties in the process control. Hence, the combination is recommended for the treatment of the textile effluents. ª 2014 Production and hosting by Elsevier B.V. on behalf
Journal of Water Process Engineering, 2019
The present study deals with the treatment of real effluents, containing a mixture of reactive dyes (mainly methylene blue), by electrocoagulation (EC) coupled with electrochemical advanced oxidation processes (EAOPs) such as peroxi-coagulation (PC), anodic oxidation (AO), and electro-Fenton (EF), individually. To choose the right treatment process, the key criteria should be higher degradation efficiency and minimal energy consumption. Textile effluents are physico-chemical characterized and the operating parameters i.e. the initial pH, the current density, and the electrolysis time, were investigated. Wastewater treatment energy consumption was evaluated for each combined process. The results highlighted high efficiency of electrochemical processes in effective degradation of organic pollutants at the optimum operating conditions. Among the electrochemical advanced oxidation processes tested, sequential EC-EF treatment was being preferred and quite effective since it provided electro generated hydroxyl radical % OH especially when using the boron-doped diamond. Thus, removals of 97%, 100% and 100% for, respectively, TOC, turbidity and color removal were achieved by using the EC-EF combined process. Energy consumption values were evaluated for textile dye decolorization as 0.45-1.5 kW h kg −1 of the removed TOC, depending on the applied current density. Regarding the efficiency level and the operating cost, the EC-EF combined process offers many advantages allowing the reuse of the treated water for other purposes.
Materials, Energy and Environment Engineering, 2017
The textile industry is one of the prevailing industry practicing enormous amount of dyes, fibers and other chemicals in different production practices including dyeing, bleaching and finishing. Approximately 100,000 dyes are commercially available with an estimated annual production exceeding 700,000 tons, and nearly 30 % of these dyes are gone astray along with wastewater. So it becomes a necessity to treat the wastewater before discharge. More than 2500 textile weaving industries and 4200 textile finishing factories are established in India. The major pollutants from textile wastewater mainly including surfactants, finishing agents, metal complexes, inhibitor compounds, ionic compounds, dyeing substances, phosphates, dissolved and suspended solids. Textile wastewater has been observed to have high COD values, strong color, immense TDS and varying pH. Therefore, due to large quantities of pollutants present in wastewater, textile industries suffer a lot of problems in discharging the same. Various methods have been proposed for effluent treatment, including Fentons method, ozonation, photochemical treatment, coagulation, adsorption, biological method and electrochemical treatment (Khandegar and Saroha 2013). Due to use of numerous chemicals in the physical, chemical and biological methods these are inefficient for effective treatment. Hence the industrial operators are searching for better methods to solve their wastewater treatment problems.
Journal of The Textile Institute, 2020
Color is one of the main problems in wastewater and many techniques can be applied to remove it. In the present work, a pilot plant scale investigation was carried out to optimize treatment efficiency in order to reduce the amount of residual adsorbed dye that will be found in the waste sludge. For degradation of textile wastewater (TWW), coagulation-flocculation experiments were performed in a jar test apparatus using FeCl 3 , Fe(SO 4), Al 2 (SO 4) 3 and Cu(SO 4) as a coagulant agent and three bacteria (Sphingomonas paucimobilis, Bacillus sp. and filamentous bacteria) by means of biodegradation, coagulation-flocculation process and their combination. The color, COD and phenol removal were 81.82%, 76.17% and 35.69% respectively. UV-vis and nuclear magnetic resonance (NMR) spectroscopy analysis confirmed the biodegradability of the TWW by post and pre-treatment of the developed bacterial consortium. The textile wastewater phytotoxicity assessment on Sorghum bicolor and Triticum aestivum showed 80% and 60% reduction after post-treatment textile wastewater.
Frontiers in Microbiology, 2021
Wastewater discharge is a matter of concern as it is the primary source of water pollution. Consequently, wastewater treatment plays a key role in reducing the negative impact that wastewater discharge produce into the environment. Particularly, the effluents produced by textile industry are composed of high concentration of hazardous compounds such as dyes, as well as having high levels of chemical and biological oxygen demand, suspended solids, variable pH, and high concentration of salt. Main efforts have been focused on the development of methods consuming less water or reusing it, and also on the development of dyes with a better fixation capacity. However, the problem of how to treat these harmful effluents is still pending. Different treatment technologies have been developed, such as coagulation-flocculation, adsorption, membrane filtration, reverse osmosis, advanced oxidation, and biological processes (activated sludge, anaerobic-aerobic treatment, and membrane bioreactor)....