The effect of nitrogen supplementation on the efficiency of colour and COD removal by Malaysian white-rot fungi in textile dyeing effluent.

White-rot fungi, namely Coriolus versicolor and Schizophyllum commune, were studied for the biodecolorization of textile dyeing effluent in shaker-flask experiments. The results showed that C. versicolor was able to achieve 68% color removal after 5 days of treatment while that of S. commune was 88% in 9 days. Both fungi achieved the above results in non-sterile condition with diammonium hydrogen phosphate as the nutrient supplement. On the other hand, the best COD removal of 80% was obtained with C. versicolor in 9 days in sterile effluent with yeast extract as nutrient supplement, while S. commune was able to remove 85% COD within 8 days in non-sterile textile effluent supplemented with diammonium hydrogen phosphate.     

Effect of ozone, chlorine and hydrogen peroxide on the elimination of colour in treated textile wastewater by MBR.

In treating textile wastewater, the application of membrane bioreactor (MBR) technology showed high efficiency in COD and BOD5 removal. However, insufficient colour removal was achieved for possible reuse. The aim of the work presented in this paper was to test the performance of chemical advanced oxidation on the elimination of the colour downstream of an MBR. To improve the quality of the membrane bioreactor effluent three different oxidation treatments were tested at lab-scale: ozonation, chlorination and hydrogen peroxide oxidation. Colour, COD and BOD5 were controlled in order to assess the effectiveness of each process. For chlorination, even with 250 mg/L (active chlorine) only 80% colour removal (SACin = 14; SACout = 2.8) was achieved which is considered unsatisfactory. For hydrogen peroxide, the colour removal was even poorer; it was just 10% at a concentration of 250 mg/L. In contrast, good results were obtained by ozonation. By using only 38 mg/L within 20 minutes, it was possible to achieve the reuse recommendation with a satisfactory colour removal of 93% (SACin = 14; SACout = 0.98). The results showed that ozonation was the most promising method.     

臭氧对二级出水中溶解性有机物的氧化特性

利用臭氧对二级出水进行深度处理对于缓解北方地区河流污染问题具有重要意义。为了探究臭氧对二级出水中溶解性有机物的氧化特性,在取自北京市砂河污水处理厂二级出水的水样中分别持续通入不同浓度的臭氧,检测60min内各水样中溶解性有机碳(DOC)、紫外吸收光谱、荧光光谱、分子量分布随时间变化情况。结果发现:水样中DOC去除率与臭氧浓度和通入时间呈正相关,在臭氧浓度为1.31mg/L、通入时间为60min时,可达到最大DOC去除率(70%);通入臭氧5min时,水中溶解性有机物的荧光特性基本消失;紫外吸光度值部分减少;分子量为5～6kDa、1～3kDa和400Da的有机物显著减少,部分转化为分子量为60Da的有机物。经过臭氧氧化处理,二级出水中有机物含量显著减少,大分子有机物几乎被全部降解。     

Effect of chemical treatment on the acute toxicity of two commercial textile dye carriers.

In the present experimental study, the effect of chemical treatment (coagulation-flocculation) on the acute toxicity exerted by two commercial dye carriers (called Carrier A and B herein) often used in the textile industry was investigated. Two different test organisms were selected to elucidate the situations in activated sludge treatment systems (activated sludge microorganisms) as well as in receiving water bodies (ultimate marine discharge). According to the results of a comprehensive analysis covering COD removal efficiencies, sludge settling characteristics and operating costs involved in coagulation-flocculation, the optimum treatment conditions were defined as follows; application of 750 mg/L ferrous sulphate at a pH of 9.0 for Carrier A; and application of 550 mg/L ferrous sulphate at a pH of 9.0 for Carrier B. The acute toxicities of both dye carriers towards marine microalgea Phaeodactylum tricornutum could be reduced significantly after being subjected to coagulation-flocculation. Fair toxicity removals (towards heterotrophic mixed bacterial culture accommodated in activated sludge treatment) were obtained with coagulation-flocculation for both of the carriers under investigation.     

水环境中PPCPs的臭氧氧化和高级氧化技术

药物和个人护理用品(PPCPs)是最近十年引起关注的一类新型有机微量污染物,其对人类健康和生态环境安全的影响受到了越来越多的关注.传统的给水处理和污水处理工艺都不能有效去除水中的PPCPs,因此有必要采用臭氧氧化、高级氧化等工艺进行深度处理.臭氧是选择性氧化剂,其与PPCPs的反应受PPCPs的基团电子特性和溶液pH的影响;高级氧化技术产生的羟基自由基·OH氧化能力强,与PPCPs的反应没有选择性,主要包括O_3/H_2O_2、UV/H_2O_2、UV/TiO_2、芬顿和光芬顿氧化等.这些深度处理工艺的采用受一些因素的限制,同种工艺或不同工艺的组合能达到更高的去除效率.     

Degradation of wine industry wastewaters by photocatalytic advanced oxidation.

Wine industry wastewaters contain a high concentration of organic biodegradable compounds as well as a great amount of suspended solids. These waters are difficult to treat by conventional biological processes because they are seasonal and a great flow variation exists. Photocatalytic advanced oxidation is a promising technology for waters containing high amounts of organic matter. In this study we firstly investigated the application of H2O2 as oxidant combined with light (artificial or natural) in order to reduce the organic matter in samples from wine industry effluents. Secondly, we studied its combination with heterogeneous catalysts: titanium dioxide and clays containing iron minerals. The addition of photocatalysts to the system reduces the required H2O2 concentration. Although the H2O2/TiO2 system produces higher efficiencies, the H2O2/clays system requires a H2O2 dosage between three and six times lower.     

臭氧及其高级氧化工艺对消毒副产物的控制研究

饮用水处理中产生的消毒副产物(DBPs)具有致癌致突变等健康风险,且其在水中广泛存在,引起了水处理行业的广泛关注。DBPs的前体物主要是消毒前未被水处理工艺去除,且能与消毒剂反应形成DBPs的有机物或无机离子。在消毒前,通过增设新的处理工艺(如预处理或深度处理工艺)以去除DBPs前体物,是控制DBPs的有效措施。臭氧及其高级氧化工艺能够有效氧化降解部分有机污染物,所以其已经成为控制某些典型DBPs的重要工艺。综述了臭氧及其高级氧化技术对典型DBPs——三卤甲烷及卤乙酸的控制效果,详细讨论了这些技术的降解效率、机理及反应动力学,以期为微污染原水条件下DBPs的有效控制提供有益参考。     

On the effect of pharmaceuticals on bacterial nitrite oxidation.

Pharmaceuticals or their metabolites are partially excreted with urine or faeces ending up in raw sewage. Many of these substances are not biodegradable and their presence in influents of municipal wastewater treatment plants may cause adverse effects to sensitive biological processes such as nitrification, while on the other hand, they may go through the activated sludge process unreacted. The second step of nitrification, i.e. oxidation of nitrite to nitrate is particularly sensitive. Inhibition of this step under uncontrolled conditions may lead to accumulation of nitrite nitrogen in the plant effluent, a form of nitrogen which is particularly toxic. The effects caused by the presence of seven different pharmaceuticals to a culture of nitrite-oxidizing bacteria isolated from activated sludge are presented. These pharmaceuticals were ofloxacin, propranolol, clofibrate, triclosan, carbamazepine, diclofenac and sulfamethoxazole. Different effects were observed for each of the pharmaceuticals tested in this study. In the cases of ofloxacin and sulfamethoxazole significant inhibition was observed. Triclosan presented a substantial inhibitory effect on the substrate (nitrite) reduction rate. The long-term effect of triclosan on nitrite oxidizers was also examined in a CSTR reactor and conclusions were drawn regarding the reversibility of the inhibition caused by this compound.     

The effects of polymer characteristics on nano particle separation in humic substances removal by cationic polymer coagulation.

Removal of humic substances by coagulation involves nano- and microparticle transport processes. The objective of this paper has been to describe the effects of polymer characteristics on the initial coagulation of nano-sized humic substances and on the aggregates' ability to form larger flocs. The study offers a direct comparison of four different low molecular weight polycations, with charge densities ranging from 4.0 to 7.0 meq/g, as well as of a low and medium molecular weight cationic polyacrylamide with practically equal charge densities. The extent of coagulation of humic substances, determined as the percentage removal of humic substances after filtration through 0.1 microm, could, regardless of the polymer type, be explained by the amount of cationic charge equivalents added per mg TOC of humic substances. The optimal polymer dosage with respect to the extent of flocculation, determined as the percentage removal after filtration through 11 microm could not be explained by this, but the maximum extent of flocculation obtained with each polymer type increased with increasing polyelectrolyte charge density. However, the weak polycation chitosan showed a significantly higher maximum extent of flocculation than would be predicted from its charge density. Polyelectrolyte molecular weight did not show any significant effect on the coagulation of humic substances, nor did it increase the extent of floc separability at 11 microm.     

pH对粉末活性炭去除有机物的影响

粉末活性炭去除水中有机物的效果受水的pH影响较大。降低水的pH,可显著提高粉末活性炭去除有机物的效果。对于黄浦江水,当pH为5.5,粉末活性炭投加量为40mg/L时,DOC和UV_(254)的去除率分别达到43.8％和36.2％。     

Model experiments on improving nitrogen removal in laboratory scale subsurface constructed wetlands by enhancing the anaerobic ammonia oxidation.

Anaerobic ammonia oxidation (Anammox) has been identified as a new general process-strategy for nitrogen removal in wastewater treatment. In order to evaluate the role and effects of the Anammox process in wetlands, laboratory-scale model experiments were performed with planted fixed bed reactors. A reactor (planted with Juncus effusus) was fed with synthetic wastewater containing 150-200 mg L(-1) NH4+ and 75-480 mg L(-1) NO2(-). Under these operating conditions, the plants were affected by the high ammonia and nitrite concentrations and the nitrogen removal rate fell within the same range of 45-49 mg N d(-1) (equivalent to 0.64-0.70 g Nm(-2)d(-1)) as already reported by other authors. In order to stimulate the rate of nitrogen conversion, the planted reactor was inoculated with Anammox biomass. As a result, the rate of nitrogen removal was increased 4-5-fold and the toxic effects on the plants also disappeared. The results show that, in principle, subsurface flow wetlands can also function as an "Anammox bioreactor". However, the design of a complete process for the treatment of waters with a high ammonia load and, in particular, the realisation of simple technical solutions for partial nitrification have still to be developed.     

混凝沉淀工艺对不同优势藻类的去除特性研究

为了考察混凝沉淀工艺的除藻性能在不同藻类优势期内的变化,将试验过程分为绿藻优势期和蓝藻优势期两个阶段,进行进水藻类群落结构特征及其变化对混凝沉淀除藻效能的影响研究.结果表明,混凝沉淀在绿藻优势期和蓝藻优势期的除藻效率分别为68.3%和40.4%,且各种藻类的去除效能并无明显的相互影响.蓝藻优势期的藻类去除率大大低于绿藻优势期,其根本原因在于占优势地位的微囊藻的生理生态特征.因此,把水中的所有藻类笼统地作为一个去除对象是不适宜的,应分析水中藻类群落结构特征,并根据特定原水中的优势藻种类进行针对性的除藻方案研究.     

Comparison of the efficacy of oxidative processes and flocculation for the removal of colour from Eop effluent.

Up to 30% of the released colour arising from bleached kraft pulp and paper production comes from the alkaline extraction stage. This waste stream can therefore be readily targeted to remove colour at source in mills where improved colour management is required. The efficacy of five advanced oxidative treatment and physico-chemical technologies in removing colour from a typical Eop stage effluent was compared. The most effective oxidative treatment was peroxymonosulphate (79% colour removal in 15 minutes). Ozone and TAML treatments removed 74% and 58% of colour respectively within 30 minutes. In comparison, hydrogen peroxide alone was only able to remove 35% of the colour over 4 hours. Coagulation with polyaluminium chloride achieved 89% colour removal within 5 minutes. However, this treatment produced an undesirable sludge, and may cause toxicity in the treated wastewater. Overall, colour removal ability of the five technologies ranked from highest to lowest was polyaluminium chloride > peroxymonosulfate > ozone > TAML > hydrogen peroxide. Other factors, such as operating costs, feedstock modification and capital infrastructure, also need to be taken into account when selecting the most suitable colour management option.     

活性炭-纳米二氧化钛电催化氧化处理染料废水

采用吸附、焙烧法制备活性炭-纳米二氧化钛催化剂,对偶氮染料甲基橙溶液进行电催化氧化降解实验。考察催化剂量、槽电压、pH值、电解质浓度、反应时间等因素对处理效果的影响,探讨该法对COD和色度的去除机制;并以水杨酸为探针性物质,推测出电催化氧化过程中羟基自由基.OH的产生。     

田间尺度下土壤水流非均匀运动特征的染色示踪研究

根据碘和淀粉的显色反应原理对土壤优先流进行了示踪研究,开展了入渗水量深度分别为 20mm、40mm、60mm和80mm的4组染色示踪试验。通过对垂直剖面流动模式的分析和对整个试验区域入渗深度分布的统计分析,研究了土壤水流运动的非均匀特征与入渗初始条件和边条件之间的关系。研究结果表明：(1)土壤水流运动在剖面内和剖面之间均表现出明显的变异特征;(2)土壤初始含水率升高对土壤优先流的发展有明显的抑制作用、降低了入渗在剖面内和剖面间的变异程度;(3)随着入渗水量的增大,土壤水入渗的非均匀程度非线性减小,但过多的增大入渗水量对提高入渗均匀度的作用有限;(4)互相关函数分析可成功地用来研究土壤水流入渗变异特征的方向性、比较入渗在剖面内和剖面间变异程度的大小以及确定入渗区域中土壤优先流的可能最大宽度。     

Advanced oxidation of commercial textile biocides in aqueous solution: effects on acute toxicity and biomass inhibition.

In the present study, the decomposition of two biocides used in the textile finishing process with Advanced Oxidation Processes (AOPs) has been studied. Different AOPs, i.e O3/OH-, TiO2/UV-A and Fe2+/H2O2 have been used representing mutually combined components of the chemically and photochemically driven advanced oxidation systems. The course of reaction was examined by changes in chemical oxygen demand (COD), total organic carbon (TOC) and acute toxicity towards the water flea Daphnia magna (assessed in terms of the effective dilution ratio LD50). Particular attention has been paid to determine the inhibitory effect of raw and ozonated biocides on biological activated sludge consortium at concentrations typically encountered in textile finishing effluents. Significant oxidation and mineralization of both biocides could be achieved employing ozonation at pH = 11.5 and heterogeneous photocatalysis (TiO2/UV-A) at pH = 5.0, whereas Fenton's reagent appeared to be less effective in COD and acute toxicity abatement.     

不同吸附材料对水中高氯酸盐的去除效果比较研究

首先通过高氯酸盐的吸附平衡实验,比较8种不同吸附材料的吸附能力。实验结果表明:对高氯酸盐吸附,Langmuir模型拟合效果要优于Freundlich模型,吸附类型主要为单层吸附。对不同吸附材料的高氯酸盐吸附自由能计算也得出,高氯酸盐的吸附主要为化学吸附。8种材料吸附能力由大到小依次为:阴离子交换树脂>木质活性炭>椰壳活性炭>煤质活性炭>壳聚糖>沸石>膨润土>颗粒氢氧化铁。研究中还对高氯酸盐的吸附动力学进行探讨。并对吸附动力结果进行了一级和二级动力学方程拟合。二级拟和的线性相关系数明显高于一级。说明不同材料对本研究中所使用的高氯酸盐的吸附更符合二级动力学方程。对吸附速率的比较则得出,阴离子交换树脂和活性炭的吸附速率要明显高于其他吸附材料。     

污水再生处理雾化曝气臭氧氧化系统运行费用分析

雾化曝气臭氧氧化是利用近年来倍受关注的微米气泡将臭氧溶入水中的一项新技术。系统掌握雾化曝气臭氧氧化系统运行费用及其影响因素,对降低其运行成本具有重要意义。影响雾化曝气臭氧氧化系统工程运行费用的主要因素有臭氧投加量、臭氧气体浓度、气液比及循环泵过流水量等工艺参数,其中臭氧投加量和臭氧气体浓度的影响最大。在保证处理效果的前提下,减少臭氧投加量、提高臭氧气体浓度及加大气液比,是有效降低微米气泡发生设备运行费用的关键。研究结果表明,在其他条件相同的情况下,雾化曝气臭氧氧化系统的臭氧投加量需低于微孔曝气臭氧氧化系统的臭氧投加量30%～40%,其运行费用才有优势。     

The effects of dissolved organic matter on the decomposition of di-n-butyl phthalate by ozone/hydrogen peroxide process.

The effects of the dissolved organic matter (DOM) on the ozone decay and the di-n-butyl phthalate (DBP) decomposition during ozone/hydrogen peroxide (O3/H2O2) process were investigated (DBP-d4 was used instead of DBP). Four surface waters, two secondary municipal sewage effluents (SMSEfs) and Suwannee river natural organic matter were used as DOM. The ozone decompositions in the DOM solutions were separated by instantaneous ozone consumption and slower ozone decay. The effect of H2O2 addition on the ozone decay was clearly observed at slower ozone decay. Ozone decomposition rate at slower ozone decay increased linearly with H2O2 dose. DBP-d4 was exponentially decreased with ozone consumption. Ozone consumption required to decompose 90% of DBP-d4 ((deltaO3)90%) in SMSEFs was higher than those in surface waters. The (deltaO3)90% per DOC of DOM values were from 22 to 23 micromole/mgC for SMSEFs and from 10 to 17 micromole/mgC for surface waters. The (deltaO3)90% values were correlated to specific ultraviolet absorbance at 254 nm (SUVA254) for surface waters.     

Heterogeneous catalytic oxidation of hypophosphite by H2O2: pH effect.

Phosphorus chemicals control key aspects of eutrophication and other environmental process. Hypophosphite (HP) originating from manmade and natural sources was evidenced as present in the environment and was investigated rarely. Recently, iron oxide has been used as a catalyst for oxidising organic contaminants with hydrogen peroxide (i.e. heterogeneous Fenton-like reaction). This study focused mainly on the oxidation of 1.0 mM HP by hydrogen peroxide in the presence of a novel iron oxide catalyst (B1 catalyst) which was prepared through a fluidised-bed Fenton reactor (FBR-Fenton). The background experiments including the oxidation experiment of HP by air only, by H2O2 only and adsorption of HP by B1 catalyst were first elucidated. It was found that HP could not be oxidised at all by air and H2O2 at pH 2.5-12 in 24 hours. On the other hand, it could be adsorbed by B1 catalyst with 89.8% removal at pH 2.5 in 5 hours and complete desorption at pH 11.0. Then, we investigated the effects of pH and Fe leaching from the catalyst on the oxidative efficiency of HP. We found that although the removal rate of HP at pH 2.5 is faster than that at pH 4.0, B1 catalyst has a higher HP oxidation efficiency at pH 4.0 than that at pH 2.5. We conclude that it is a major heterogeneous catalytic oxidation by our novel iron oxide catalyst to oxidise HP at pH 4.0. Also, B1 could be a useful and potential catalyst for the treatment of HP wastewater.