Fenton氧化对印染污泥脱水性能的影响

采用Fenton氧化法对印染污泥进行预处理,研究印染污泥中TSS、VSS、CST、SRF等脱水性能指标的变化规律.结果表明,当pH值为2.0,H2O2和Fe2+投加量分别为428 mg.g-1(干泥)和42.8 mg.g-1(干泥),反应时间1.5 h、反应温度80℃时,Fenton氧化后印染污泥的脱水效果最佳.在该条件下,TSS由18.66 g.L-1下降至4.82 g.L-1,去除率为74.17%;CST和SRF分别由98.6 s和6.03×1011s.2g-1下降至18.9 s和8.42×1010s.2g-1;污泥的平均粒径和中值粒径分别由53.8μm和42.9μm下降至19.8μm和16.2μm.     

还原铁法处理印染废水生化出水及原理

采用还原铁粉处理印染废水生化出水,以ADMI7.6作为主要测试指标,考察铁粉投加量、反应时间以及进水pH对出水水质的影响,并研究在此过程中铁粉还原作用和混凝絮凝作用对整体效果的贡献比.结果表明,条件1:铁粉投加量=1.0 g.L-1,反应时间150 min,进水pH 2;条件2:铁粉投加量1.0 g.L-1,反应时间150 min,进水pH 3.条件1时,ADMI7.6去除率达到80%,但铁泥量大,酸碱消耗大,在此反应条件下,铁粉还原去除40%,混凝絮凝去除60%;条件2时,ADMI7.6去除率达到50%左右,产铁泥量小,经济合理;在此反应条件下,铁粉还原去除55%—63%左右,混凝絮凝去除37%—45%左右.经XAD8/XAD4树脂联用,分析疏水酸、非酸疏水物质、弱疏水物质及亲水物质4类有机物的去除情况表明,条件1时,能够高效去除非酸疏水物质,去除率为95%,对于疏水酸以及弱疏水物质也有一定的去除效果;条件2时,对4类有机物去除均有一定作用,但对于非酸疏水物质以及疏水酸的去除效果要略差于条件1.     

A study on genotoxicity of textile dyeing industry effluents from Rajshahi,Bangladesh, by the Allium cepa test

Textile dye effluents are believed to be toxic as they might exert various harmful effects on living organisms including genotoxicity. These effluents are the main source of direct and continuous input of pollutants into the aquatic ecosystems. In this study, dye effluents from a local silk dyeing industry were analysed for their genotoxic potential by the Allium cepa genotoxicity test. The A. cepa test is characterised as a genotoxicity test where the roots of A. cepa are grown in different concentrations of the test material. The macroscopic results clearly showed that the toxicity of the dye effluents prompted A. cepa root growth inhibition, and this effect increased with higher concentrations of the effluents. At the cellular level, no dividing cells were found at higher concentrations such as 60%, 80% and 100% of the effluents. However, at a lower concentration of 20%, dividing cells were identified, although the mitotic index was much lower than that of the control. Microscopic analysis showed that the dye effluents induced chromosomal aberrations at significant levels. Taken together, these results revealed that the textile dyeing industry effluents are toxic to eukaryotic cells and these dyes have genotoxic properties that can potentially lead to cancer development and adverse health conditions.     

印染废水生化出水高锰酸钾强化混凝深度处理溶解性有机物的去除特性

采用高锰酸钾预氧化,强化某印染废水生化出水铁盐混凝深度处理溶解性有机物(DOM),考察了高锰酸钾强化混凝对印染废水生化出水中DOM的去除特性并为优化混凝深度处理工艺提供理论参考.在最优投加条件下,高锰酸钾强化混凝处理提高了DOM色度的去除效果,以美国染料生产协会色度值(ADMI7.6)表征时为84%,出水ADMI7.6值较单独混凝处理降低了43%.但以溶解性有机碳(DOC)表征时去除率基本保持不变,为55%.通过XAD-8/XAD-4吸附树脂分离技术和分子量分布分析发现,高锰酸钾强化混凝处理通过有效去除疏水性和弱疏水性DOM色度降低了出水的色度.同时,出水中亲水性和小分子DOM(MW<1 kDa)较单独混凝处理分别增加了34%和15%,导致了DOM去除率以DOC表征时无显著改善.采用三维荧光光谱技术定性分析表明,引起色度的可见类富里酸和类腐殖酸物质被进一步去除使出水色度降低,此时出水中增多的小分子亲水性DOM主要为类蛋白质和富里酸物质.因此,高锰酸钾强化混凝处理过程仍需与其它能去除亲水性、小分子量DOM(MW<1 kDa)的处理工艺结合,以提高总体去除效率.     

典型印染废水处理过程中芳香烃化合物的污染特征及污泥生态风险评价

采用GC-MS测定了典型综合印染废水处理厂废水和污泥中芳香烃化合物的含量.结果表明,原水中苯系物总量为203.96±15.18μg·L-1,其中二甲苯占62.7%,尾水中苯系物总量为0.2±0.029μg·L-1,整个处理工艺对苯系物的去除效率为99%.原水中多环芳烃(PAHs)总浓度达1349.51±35.77 ng·L-1,以3—6环为主,主要富集在颗粒物上.整个工艺对PAHs的去除效率为95%,尾水中PAHs总浓度为65.81±20.99ng·L-1,以2—3环为主.干污泥中PAHs含量高达2996.10±151.0 ng·g-1,污泥吸附为水相中PAHs去除的主要机理之一.印染污泥直接填埋或农用会引起潜在的生态危害.     

印染废水生化出水中有机污染物特性及在硫酸镁混凝过程中的去除行为

以某印染废水二级生化出水为研究对象,考察了生化出水中有机污染物中各组分含量、分子量分布特点等特性,以及各类有机物在硫酸镁混凝处理过程中的去除行为.实验结果表明,该印染废水的生化出水溶解性有机物的主要成分是疏水性物质,以溶解性有机碳（DOC）表征时占总DOC的78%,其中非酸疏水物质约占46%,而以UV254表征时约占总55%,以美国染料生产协会色度值（ADMI7.6）表征时为97%,其中以非酸疏水物质的贡献最大,达到66%,并且非酸疏水物质中不饱和双键或芳香环有机物的含量较高.生化出水中的DOC主要集中在小于1000 D的有机物上,占37%.在硫酸镁的最佳混凝条件下,可以有效地去除由大分子量的非酸疏水物质引起的色度,而对小分子量的有机物也有一定的去除效果.     

Sustainable co-evolution

Humankind is dependent upon Earth's ecological life support system, whose well-being, in turn, depends upon the practices of human society. The health of both systems requires harmonious, mutualistic interactions between them. Because of its population size and demographic distribution (increasingly urbanized), humankind is also dependent upon its technological life support system, which, as currently managed, threatens the ecological life support system. A fundamental difference exists between the two systems—humankind is capable of using intelligence and reason to regulate its activities but the 30+ million other life forms that comprise the ecological life support system cannot. As a consequence, empathy for the other system is the responsibility of human society. Sustainable co-evolution requires that human society has a high level of ecological literacy and acts in a nurturing, compassionate way toward the other system. Only then will sustainable co-evolution be possible since both systems are dynamic and continually changing.     

Polyurethane for removal of organic dyes from textile wastewater

Synthetic organic dyes are extensively used in consumer products from textile to pharmaceuticals. A large amount of organic dyes is ultimately discharged as effluent into water bodies, thus posing a serious threat to environment and life. Therefore, removal of dyes from water bodies is needed. To address this problem, various synthetic and natural materials have been used to adsorb dyes. Here, we review the application of polyurethane for removal of organic dyes. First, we review the application of simple and modified polyurethane as efficient and economic adsorbents for dyes. Secondly, we review the polyurethane-based membranes for separation and adsorption of various dyes. Thirdly, we describe polyurethane composites with improved efficiency of dyes removal. Finally, we review the bioremediation of dyes where polyurethane has been proven as an excellent inert support.     

Performance of bioferric-submerged membrane bioreactor for dyeing wastewater treatment

Adding iron salt or iron hydroxide to sludgemixed liquor in an aeration tank of a conventional activated sludge processes (bioferric process) can simultaneously improve the sludge’s filterability and enhance the system’s treatment capacity. In view of this, Fe(OH)₃ was added to a submerged membrane bioreactor (SMBR) to enhance the removal efficiency and to mitigate membrane fouling. Bioferric process and SMBR were combined to create a novel process called Bioferric-SMBR. A side-by-side comparison study of Bioferric-SMBR and common SMBR dealing with dyeing wastewater was carried out. Bioferric-SMBR showed potential superiority, which could enhance removal efficiency, reduce membrane fouling and improve sludge characteristic. When volumetric loading rate was 25% higher than that of common SMBR, the removal efficiencies of Bioferric-SMBR on COD, dye, and NH₄ ⁺-N were 1.0%, 9.5%, and 5.2% higher than that of common SMBR, respectively. The trans-membrane pressure of Bioferric-SMBR was only 36% of that in common SMBR while its membrane flux was 25% higher than that of common SMBR. The stable running period in Bioferric-SMBR was 2.5 times of that in common SMBR when there was no surplus sludge discharged. The mixed liquor suspended solids concentration of Bioferric-SMBR was higher than that of common SMBR with more diversified kinds of microorganisms such as protozoans and metazoans. The mean particle diameter and specific oxygen uptake rate of Bioferric-SMBR were 3.10 and 1.23 times the common SMBR, respectively.     

Mutagenicity assessment of textile dyes from Sanganer (Rajasthan)

Sanganer town, district Jaipur (Rajasthan, India) is famous worldwide for its hand block dyeing and textile printing industries. These industries use a variety of chemicals and dyes during processing and finishing of raw materials. Most of the textile dyes used by these industries have not been evaluated for their impact on health and the environment. The workers in these industries are exposed to such dyes with no control over the length and frequency of exposure. Further, untreated and sometimes even treated effluents from these industries are released into surface waters of Amani Shah drainage or through the drainage systems, seep into the ground water and adjoining water bodies. Since many textile dyes are known carcinogens and mutagens, a complete evaluation of the safety of these dyes in the human environment must include an evaluation of their genotoxicity or mutagenicity. A total of 12 textile dyes from Sanganer were tested for their mutagenicity, by Ames Salmonella reversion assay using strain TA 100 of Salmonella typhimurium. Only 1 dye, Red 12 B showed absence of mutagenic activity. The remaining 11 dyes were all positively mutagenic.     

Sustainable development as freedom

There has been considerable debate about how best to define sustainable development. In this commentary, I argue that Amartya Sen's concept of 'development as freedom' is the appropriate theoretical framework for understanding sustainable development. Environmentalists should consider defining their goal as 'sustainable development as freedom,' the achievement of the greatest possible level of freedom without restricting the access of future generations to these same freedoms. The adoption of this framework has implications for the work of environmental NGOs, which are briefly discussed.     

Removal of textile dyes from water by the electro-Fenton process

An environmentally friendly electrochemical treatment, electro-Fenton process, was applied to the depollution of a synthetic dismissal composed of three dyes, yellow drimaren, congo red and methylene blue, frequently used in textile and dyehouses. Here, we show that those dyes and their mixture are quickly degraded under current controlled electrolysis conditions, leading to an almost complete mineralization. The results show the efficiency of electro-Fenton process to quickly degrade aqueous effluents polluted by synthetic organic dyes.     

臭氧氧化印染废水生化出水的生化降解特性

测定了不同比臭氧消耗量条件下,印染废水生化出水中生化可降解溶解性有机碳（BDOC）在28 d内的变化过程,并对接种培养前后的三维荧光光谱进行了分析.结果表明,臭氧氧化能有效降低印染废水生化出水的色度和芳香度,明显提高可生化性.在比臭氧消耗量2.7 mg.mg-1条件下,预计臭氧氧化和生物滤池联用技术对DOC的去除率约为54%.另外,亲水性有机物对BDOC的贡献率与比臭氧消耗量呈正比关系.类腐殖和类色氨酸物质的荧光强度在一定程度上反映了生化难降解有机物的含量.     

Treatment of textile dye wastewater using ozone combined with photocatalyst

Ozonolysis combined with photocatalysis was used as a new approach for the treatment of textile dye wastewater containing azo dyes. The color reduction was very fast when only ozone was used for the treatment, but a 90% Total Organic Carbon (TOC) reduction was obtained only during a combined treatment. Reactive Black 5 dye containing two different percentages of NaCl was used for the experiment. The color reduction was fast in the neutral and basic pH. However for a fast TOC reduction acidic pH was found to be more effective. On‐line UV‐Vis spectrophotometry was used to measure the color reduction.     

Treatment of dyeing wastewater using coal fly ash as co-coagulant

This article deals with the co-coagulation of dyeing wastewater by coal fly ash using FeSO₄ as coagulant, Benzo Scarlet 4BS and Brilliant Acid Scarlet 3R as the testing dyes. The optimal concentration of FeSO₄ for co-coagulation process is 0.6–0.8?g/L wastewater, and the concentration of fly ash 4–5?g/L. The experimental results show that the co-coagulation process by fly ash helps to improve the color reduction, greatly accelerate the formation and settling of the floc, and reduce the content of the floc. The mechanism for co-coagulation process is discussed and similar effect is obtained when the co-coagulation method is applied for the treatment of the real dyeing wastewater samples.     

Adsorptive removal of a synthetic textile dye using cocoa pod husks

The adsorption of a synthetic textile dye (Remazol Brilliant Black Reactive) on cocoa pod husk-based activated carbon was investigated in batch process. The adsorbent prepared was characterized by gas adsorption surface analysis (Brunauer Emmett Teller, BET), scanning electron microscopy, and Fourier transform infrared spectroscopy. The effects of initial dye concentration, contact time, solution temperature, and solution pH were evaluated. Equilibrium data were fitted to Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherm models, the first being the best with maximum monolayer coverage of 111?mg?g^?1. Kinetic data were fitted into pseudo-first-order, pseudo-second-order, intraparticle diffusion, and Elovich models; the pseudo second-order model provided the best correlation. Maximum adsorption was observed at pH 7. Standard free energy, standard enthalpy, and standard entropy were also calculated. The adsorption interaction was found to be endothermic and spontaneous. Both the mean free energy of adsorption and the activation energy show that the mechanism is by physisorption.     

Effect of textile industrial effluent on tree plantation and soil chemistry

A field study was conducted at Arid Forest Research Institute to study the effect of textile industrial effluent on the growth of forest trees and associated soil properties. The effluent has high pH, electrical conductivity (EC), sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) whereas the bivalent cations were in traces. Eight months old seedlings of Acacia nilotica, Acacia tortilis, Albizia lebbeck, Azadirachta indica, Parkinsonia aculeata and Prosopis juliflora were planted in July 1993. Various treatment regimes followed were; irrigation with effluent only (W1), effluent mixed with canal water in 1:1 ratio (W2), irrigation with gypsum treated effluent (W3), gypsum treated soil irrigated with effluent (W4) and wood ash treated soil irrigated with effluent (W5). Treatment regime W5 was found the best where plants attained (mean of six species) 173 cm height, 138 cm crown diameter and 9.2 cm collar girth at the age of 28 months. The poorest growth was observed under treatment regime of W3. The growth of the species varied significantly and the maximum growth was recorded for P. juliflora (188 cm height, 198 cm crown diameter and 10.0 cm collar girth). The minimum growth was recorded for A. lebbeck. Irrigation with effluent resulted in increase in percent organic matter as well as in EC. In most of the cases there were no changes in soil pH except in W5 where it was due to the effect of wood ash. Addition of wood ash influenced plant growth. These results suggest that tree species studied (except A. lebbeck) can be established successfully using textile industrial wastewater in arid region.     

Biological treatments of textile industrial effluents in Lagos metropolis, Nigeria

The assessment of the effluents from two textile industries in Ilupeju in Lagos metropolis, Nigeria showed that they were high in conductivity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS) and contained traces of heavy metals like Ca, Zn but high concentrations of Cr and Pb. These wastewaters are normally discharged into neighbouring water bodies. Five bacterial groups, namely Micrococcus sp., Enterobacter sp., Alcaligens sp., Bacillus sp. and Acinetobacter sp. were isolated from these effluents. They were used individually for biotreatment and found to be able to utilize the components of the wastewaters for growth, Bacillus sp. and Acinetobacter sp. being the most efficient utilizers as they were able to reduce BOD to zero. The total viable count (TVC) increased significantly depicting growth of the bacterial population. The pH was regulated from 3.4-6.80 for NSF effluent and 12.2-10.29 for STI effluent. The work emphasises the level of industrial pollution in our environment as wastes are indiscrimately dumped into surrounding water bodies in urban areas, the textile industry being a case study. The treatment of any form of waste before disposal into the environment is important and ensures safety of the populace.