| Due to the high Chemical Oxygen Demand(COD) and chromaticity, the wastewater discharged from textile industry gradually becomes a bigger concern in the environment. With the water resources being increasingly deteriorated, the standard enforced by the government in textile wastewater discharge becomes much stricter. Therefore, it is of great technological importance and environmental value to advance the method in treatment of textile wastewater.Dissolved Organic Matter(DOM) is the primary components among the organic pollutants in textile wastewater, so the development of advanced treatment of textile wastewater will benefit from the characterization of the DOM in the process. Compared with the two-dimensional electrode, the three-dimensional electrode has been increasingly studied and applied, due to high mass transfer efficiency, high reaction rate and low energy consumption. The DOM in textile wastewater biotreated effluent was separated with resin separation and ultrafiltration, the distribution, classification and structure of DOM were characterized by the three-dimensional fluorescence spectroscopy, UV-visible spectroscopy, IR and GC-MS. The major research contents and conclusions are as follows:(1) The DOM composition of the biotreated effluent was analyzed by resin separation, the results indicated that HON, HOA, HYI, and HOB were accounted for 37.2%, 30%, 27.8% and 5% of the total COD,39.2%, 32.5%, 20.4% and 7.9% of the DOC, and 49.6%, 19.1%,30.8% and 0.5% of the UV254. In addition, they also contributed to the chromaticity with a percentage of 52.2%, 26.1%, 17.45 and 4.3%, respectively.(2) Three-dimensional fluorescence spectra showed that textile wastewater biotreated effluent mainly consisted of protein substances and fulvic acid, but with lower amount of protein substance indicated from the lower peak in fluorescence spectra. Additionally, UV-visible spectrum indicated that the wastewater contained organic compounds including benzene rings, carboxyl and hydroxy, while the infrared spectrum suggested the existence of hydrogen bond, amine substance, benzene derivatives, chloride or bromide, alcohol, ether or ketone in the effluent.(3) In the effluent, organic compounds with molecular weight smaller than 1KDa, 100 KDa~0.45 um、10~100 KDa、1~5 KDa and 5~10 KDa contributed to the total COD with a percentage of 56.9%,22.5%,13.5%,4.3% and 2.8%, the DOC with a percentage of 60.7%,20.7%,10.2%,5.4% and 3%. They were also correspondingly accounted for 73.1%,1.8%,15.5%,4.1% and 5.5% in UV 254 and 60%,20%,10%,6.67 and 3.33% in the chromaticity.(4) The results of GC-MS showed that biotreated effluent consisted of 50 different kinds of organic compounds, including eight priority pollutants: naphthalene, ethylbenzene, oleoyl chloride, o-xylene, mesitylene, chlorinated tetradecane, inter-ethyltoluene, 1-chloro-decane.(5) Textile wastewater biotreated effluent was treated by three-dimensional electrode reactor, 69.3% COD removal rate was acquired with initial COD concentration of 85.8 mg/L, under the optimal conditions with anodic plate of iron plate, cathode plate of stainless steel, particle electrodes of 1 mm columnar activated carbon, electrolysis voltage of 10 V, the initial p H of 4, with reaction time of 30 min.(6) The experimental results indicated that three-dimensional electrode reactor was effective in the removal of organic matters from textile wastewater biotreated effluent. The removal rate of hydrophobic organic compounds was better than the hydrophilic organic matter removal efficiency, organic compounds with higher molecular weight were easier to remove compared with organic compounds with smaller molecules. humic acid and fulvic acid in wastewater also could be removed effectively. Especially, the priority pollutants, including naphthalene, ethylbenzene, oleoyl chloride, o-xylene, mesitylene, chlorinated tetradecane, inter-ethyltoluene, 1-chloro-decane could also be effectively removed. The analysis indicated the reduction in the composition of conjugated radical, and the lower degree of aromatization in the treated effluent, however, the significant removal of amine substance, chloride and bromide was not observed in this process. |
PDF Full Text Request