OKRA (HIBISCUS ESCULENTUS) AND FENUGREEK (TRIGONELLA FOENUM GRACEUM) MUCILAGE:CHARACTERIZATION AND APPLICATION AS FLOCCULANTS FOR TEXTILE EFFLUENT TREATMENTS

The use of new food grade polysaccharides (mucilage) obtained from Hibiscus esculentus and Trigonella foenum graceum,commonly called Okra and Fenugreek,respectively,as flocculants was described.These polysaccharides were used for removal of solids (suspended solids (SS) and total dissolved solids (TDS)) and dyes from real textile effluents and aqueous solutions of different class of synthetic dyes.Influences of varying polysaccharide concentration,contact time and pH on removal of pollutant from the textile...

Optimization of continuous electrocoagulation-adsorption combined process for the treatment of a textile effluent

The aims of this study is to design and optimize the functioning of a full continuous combined process based on electrocoagulaion-adsorption on crude Tunisian clay to treat a real textile effluent.The clay characterization shows that the used clay is a rich-smectite clay.The response surface methodology(RSM)technique based on Box-Behnken design(BBD)was used to optimize the process.At optimum conditions which are initial pH solution of 8.24,effluent flow rate of 0.5 L·min^(-1),voltage of 70 V,and added suspension of clay flow rate of 100 ml·min^(-1) the achieved color,chemical oxygen demand(COD)and total suspended solid(TSS)removal efficiencies were respectively 96.87%,89.77%and 84.46%with0.75 USD·m^(-3) as total cost.The additional laboratory experiments at optimum conditions agree with the predicted results,which confirm the accuracy and the capability of RSM to predict results in the defined space.Finally the designed process could be a good eco-friendly alternative to treat and reuse wastewater in industrial process with reasonable cost.

Screening of Methyl Red Degrading Bacteria Isolated from Textile Effluents of Savar Area, Dhaka, Bangladesh

Physicochemical properties and metal contents of five dye-based textile effluents collected in summer and winter season, 2016 from Savar, Dhaka, Bangladesh were within the recommended acceptable limit. The average value of all physicochemical parameters was found high in summer season except turbidity. A total of 94 heavy metal resistant bacteria (46 gram positive & 48 gram negative) were isolated from textile effluent samples and among them 17 isolates were multi metal resistant. Highest tolerance level of the isolates was shown at 10 mM concentration against Pb. All the heavy metal resistant bacterial isolates were presumably grouped into 14 genera according to morphological and biochemical assay. Three isolates designated WFB3c (65.41%), WFB4g (62%) and SFB5c (60.07%) were found to potentially degrade dye as well as tolerate heavy metals. Three potential dye decolorizer isolates were screened out and most potential one (WFB3c) was identified as Proteus mirabilis according to the 16S rRNA identification. The isolated bacterial strain Proteus mirabilis would be a potential candidate for microbes based treatment to decolorize dye from textile effluents.

Treatment of Textile Dye Effluent Using a Self-made Positively Charged Nanofiltration Membrane

A selfmade positively charged nanofiltration （NF） membrane was used to treat textile dye effluent to generate water for reuse, and the factors affecting nanofiltration process such as operating pressure, feed flow and membrane cleaning were investigated. With an applied pressure of 1.0 MPa and a feed flow of 40 L/h, this NF membrane has a removal of 93.3% for CODor and a reduction of approximately 51.0% in TDS, salinity and conductivity achieving the chroma removal of 100%. The permeate obtained through this membrane is suitable for recycling. Moreover, the membrane could be reused after being cleaned with 1% NaOH solution.

Activated Carbon Adsorption Properties of the Residual Matters in Textile Dyeing and Printing Secondary Effluent

The research employed the adsorption isotherm measurement, the batch kinetic adsorption and the rapid small-scalecarbon column test （RSSCT） to find out the characteristics and main impacting factors of＇granular activated carbon （GAC） adsorption, in treating the textile dyeing-printing/polyester alkali de-weighting secondary effluent （TSE）. The adsorption affinities and capacities for the organics surrogated by CODCr, color and UV254 （UV absorbency-at λ= 254 nm） predicted by isotherm, small- seale-fixed bed were discussed. ＇Adsorption rates for CODCr, color and UV254 are much different and carbon particle size dependent. The color adsorption rate and capacity should be taken as the main consideration factors in designing bioactivated carbon filter（BACF）. The breakthrough of GAC adsorption column is mainly influenced by the low MW readily adsorbable organics in TSE. UV254, is a good adsorption breakthrough indicator. The study provides references for BACFs＇ design and operation control in textile secondary effluent （TSE） tertiary treatment.

Assessment of the Total Organic Carbon and Conductivity in Consecutive Dyeings with Reactive Dyestuffs Using Treated Effluent by UV/H202 Photocatalysis

The paper was monitored the conductivity （g.L＂l of NaCI）, the absorbances values （Abs） and the amount of TOC （total organic carbon）, before and after five consecutive dyeings made with reuse water, obtained from treated effluent by UV/H202 photocatalysis. All rates of decolorization were above 92%, the removal of total organic carbon was above 89% in all treatments and the economy of NaCI was from 3.10 in the first recipe, 3.17 in the second, 3.49 in the third, 3.79 in the fourth and 4.05 in the fifth recipe. The five dyeings compared with same dyeings made with deionized water presented a color deviation （AE＊） below 1. The conventional dyeings would consume 80 L/kg against 40 L/kg used in the dyeing process proposed in this study, representing a great economy of water, with no discharge of effluents.