饮用水源中藻毒素污染控制研究

藻毒素给传统净水工艺带来了诸多不利影响,增加了水处理难度。通过对国内外饮用水源藻毒素去除技术的分析,揭示了各种技术去除效果、局限性,对藻毒素研究前景进行了展望。提出综合控制办法:水污染综合治理、采用臭氧活性炭工艺和生物调控法相结合。     

饮用水处理中藻毒素污染及其工艺控制特性研究

有毒藻类在富营养化水源水中大量繁殖形成极富危害的藻毒素污染。藻毒素在水环境的迁移转化受光照、温度、有机物、水生生物等因素的共同影响。好氧条件下 ,已驯化的微生物对水中藻毒素的降解较为迅速。水处理的单元工艺 (混凝、沉淀、砂滤、加氯等 )及其组合的常规工艺对藻毒素的去除率较低 ,而常规工艺 +活性炭过滤、臭氧 +常规工艺两种工艺能 10 0 %地去除水中的藻毒素。不破坏藻细胞而能够大量降低其数量的预处理 +臭氧 +常规工艺 +活性炭工艺应能够取得最佳的解毒效果。     

TiO_2在饮用水膜处理技术中的应用研究进展

对于微污染水源水中天然有机物(NOMs)、藻毒素、农药等有毒有害物质,常规的水处理工艺不仅去除效果十分有限,而且会增加消毒副产物。膜分离技术是有效的解决方法之一,但如何制备新型膜材料、减少膜污染是实现膜分离技术在饮用水生产中应用的关键技术;TiO2催化氧化与膜处理技术联用后,可以提高膜通量,杀死细菌和有效减轻膜污染;在膜制备过程中TiO2不仅可以直接制备成膜,而且还可以杂合无机膜或有机膜制备复合膜,能够明显改善膜的亲水性,提高膜通量,在膜分离过程中同时具有催化性能。     

利用超滤法去除藻类的试验研究

以藻、微囊藻毒素(Microcystin,MCYST)为研究对象,考察了超滤在不同的水温透膜压力、藻含量、膜污染程度下对藻的去除效果,同时研究了超滤对池塘水中囊藻毒素的去除情况,初步探讨了超滤除藻技术应用于水厂生产实际的可能性.     

压力强化混凝沉淀过滤除藻工艺中藻毒素去除研究

为了探究压力强化混凝沉淀过滤除藻工艺中藻毒素的去除效果,试验对比研究了预加压和预氧化后的含藻水,经混凝沉淀、粉末活性炭吸附后的藻毒素去除效果,考察了不同粉末活性炭投加点及投加量对藻毒素去除效果的影响。结果表明,含藻水加压后混凝沉淀,藻类和浊度物质去除效果最优,蓝藻去除率达到96.2%,浊度降至0.49NTU。含藻水在加压和高锰酸钾预氧化后,水中藻毒素浓度未增加,而次氯酸钠预氧化后水中藻毒素浓度最大增幅为215.78%;对于加压水样,在混凝剂投加前30min或投加后7min投加粉末活性炭效果较好,粉末活性炭投加量为5~20 mg/L时,沉淀水藻毒素平均去除率分别达54.13%和53.57%,而与混凝剂同时投加则效果不佳。对次氯酸钠预氧化的水样,粉末活性炭与混凝剂同时投加时效果最好,沉淀水藻毒素平均去除率15.84%。     

水源水中藻类及藻毒素控制试验研究

研究了氯、高锰酸钾、臭氧等单独预氧化及与混凝沉淀联合作用时,水源水中藻类及藻毒素含量的变化规律,发现预氧化对藻类的去除作用有限,混凝沉淀对藻毒素的去除作用也有限,而两者的联合作用可提高对藻类和藻毒素的去除效果;在合适的投加量下,藻类去除率在80%以上,藻毒素的去除率近90%,可有效减轻后续处理工艺的负荷,保障饮用水的安全。     

微囊藻毒素的处理方法研究进展

微囊藻毒素是在藻类细胞内合成的毒素,细胞死亡后释放出来并表现出毒性.本文主要综述了水体中藻毒素目前常用的各种物理、化学、生物以及低温等离子体灭活技术等方法的国内外研究现状,介绍了影响去除的因素、机理以及存在的问题和未来研究发展的方向.     

臭氧—曝气生物滤池处理难生物降解废水的试验研究进展

臭氧与曝气生物滤池组合工艺,可提高难生物降解废水的处理效率。文章综述了该组合工艺在不同行业难生物降解废水处理中色度、COD去除率等方面的研究进展,表明组合工艺对不同原水的处理效果明显。指出臭氧与曝气生物滤池组合工艺作为一种深度处理工艺是非常适合我国国情的水处理技术,尤其对我国今后中水回用、企业污水闭路循环以及＂零排放＂...     

富营养化原水中蓝藻及其毒素的生物降解技术研究

本文主要研究以生物接触氧化作为预处理工序的富营养化原水的实用处理方法 ,以有效去除蓝藻及其藻毒素。考察了生物反应器内流态、构型对处理效果的影响 ,确定了最佳的工艺参数和处理效率 ,并初步探讨了藻类和藻毒素的降解机理。同时与传统自来水厂常规工艺处理富营养化原水中藻类及其藻毒素的处理效果相比较 ,讨论了生物预处理工艺保障水厂供水水质的积极作用。主要研究成果如下 :(1)对水厂常规工艺出水取样检测发现 ,ＮＨ3 -Ｎ ,ＮＯ2 --Ｎ ,ＣＯＤＭｎ等常规指标的去除效率普遍不高 ,藻类和藻毒素的去除效率也不理想。(2 )三阶生物接触氧…     

电化学法在钢铁企业循环冷却水处理中的研究

电化学循环水水处理技术是一种兼具杀菌灭藻、缓蚀和阻垢功能的水质稳定技术,其作用机理主要是通过电解反应,将水中的污染物通过电化学氧化、电化学还原和阴极吸附等方法去除。结合电化学设备在某钢铁冶金企业间冷开式循环冷却水处理中进行中试,通过对试验结果的分析与讨论,验证了电化学法的杀菌灭藻、缓蚀和阻垢等水质稳定效果。同时,以工程造价、运行成本方面对电化学法与传统化学药剂法进行对比分析。分析和研究了电化学设备应用于钢铁冶金企业循环冷却水处理的技术可行性和经济合理性。     

城市污水中EDCs的活性污泥法去除特性研究

以4种(壬基酚(4-n-NP),双酚A(BPA),雌二醇(E2)、乙炔基雌二醇(EE2))内分泌干扰物(EDCs)为目标物,针对其在城市污水处理厂工艺流程中的分布与去除进行了研究,并进一步实验研究了其去除机理。所有EDCs在城市污水厂进出水中均被检出,进水中平均浓度分别为E2:64.8 ng/L,EE2:171.5 ng/L,4-n-NP:115.4 ng/L,BPA:920.7ng/L;出水中平均浓度分别为E2:22.8 ng/L,EE2:49.9 ng/L,4-n-NP:50.9 ng/L,BPA:84.3 ng/L。污水中EDCs目标物的去除主要来自于生物处理阶段,其去除机理主要是生物降解,生物降解速率与EDCs种类及污泥类型有关。污泥吸附对EDCs的去除可产生一定的影响。     

Technological and hygienic consequences of reservoirs eutrophication in the Czech Republic

More than one half of drinking water demand in the Czech Republic is covered by surface water resources. The most frequent problems of the water treatment and supply are caused by the eutrophication of reservoirs. Biological parameters of drinking water quality based upon the microscopic analysis are included in local standards and commonly used in water works laboratories. Several new methods and criteria have been elaborated: microscopic evaluation of the separation efficiency of water treatment, categorization of microorganisms according to their separability, a screening bioassay for the assessment of biological stability of the water in course of the treatment and distribution, biological indicators of the eutrophication degree of reservoirs and their tributaries. A set of supplementary biological methods and criteria for special cases was published. Algal toxins have been detected not only in cyanobacterial water blooms in reservoirs but also in periphyton layers growing m different units of water works treatment trains. Two examples of the integrated system approach to the water supply from eutrophicated reservoirs inclusive of proposed preventive and remedial measures are selected from a recently finished extensive research project. Improvement actions in the resources protection, water works design and operation, laboratory control system and legislation are recommended.     

Support Vector Machines and Multilayer Perceptron Networks Used to Evaluate the Cyanotoxins Presence from Experimental Cyanobacteria Concentrations in the Trasona Reservoir (Northern Spain)

Cyanobacteria also known as blue-green algae can be found in almost every conceivable environment. Cyanobacteria blooms occur frequently and globally in water bodies and they are a major concern in terms of their effects on other species such as plants, fish and other microorganisms, but especially by the possible acute and chronic effects on human health due to the potential danger from cyanobacterial toxins produced by some of them in recreational or drinking waters. Consequently, anticipation of cyanotoxins presence is a matter of importance to prevent risks. The aim of this study is to build a cyanotoxin diagnostic model by using support vector machines and multilayer perceptron networks from cyanobacterial concentrations determined experimentally in the Trasona reservoir (recreational reservoir used as a high performance training centre of canoeing in the Northern Spain). The results of the present study are two-fold. In the first place, the significance of each biological and physical-chemical variables on the cyanotoxins presence in the reservoir is presented through the model. Secondly, a predictive model able to forecast the possible presence of cyanotoxins is obtained. The agreement of the model with experimental data confirmed its good performance. Finally, conclusions of this innovative research work are exposed.     

多氯联苯在土壤水环境中生物降解过程规律研究

土壤水环境中的有机污染物多氯联苯(PCB)可以采用土地生物处理的方法进行降解，在综合考虑土壤水环境系统中有机污染物生物降解各分过程的基础上所建立的数学模型，可以预测降解PCB所需的时间、降解程度以及降解结束后被土壤所屏蔽的PCB的量。数学模型通过美国Alcoa公司在LTU基地的大型土地生物处理工程得到了验证。利用数学模型和理论分析，预测了2，3，4和5-Cl-PCB的土地生物处理过程及规律。     

Removal of geosmin and 2-methylisoborneol by biological filtration.

The quality of drinking water is sometimes diminished by the presence of certain compounds that can impart particular tastes or odours. One of the most common and problematic types of taste and odour is the earthy/musty odour produced by geosmin (trans-1, 10-dimethyl-trans-9-decalol) and MIB (2-methylisoborneol). Taste and odour treatment processes including powdered activated carbon, and oxidation using chlorine, chloramines, potassium permanganate, and sometimes even ozone are largely ineffective for reducing these compounds to below their odour threshold concentration levels. Ozonation followed by biological filtration, however, has the potential to provide effective treatment. Ozone provides partial removal of geosmin and MIB but also creates other compounds more amenable to biodegradation and potentially undesirable biological instability. Subsequent biofiltration can remove residual geosmin and MIB in addition to removing these other biodegradable compounds. Bench scale experiments were conducted using two parallel filter columns containing fresh and exhausted granular activated carbon (GAC) media and sand. Source water consisted of dechlorinated tap water to which geosmin and MIB were added, as well as, a cocktail of easily biodegradable organic matter (i.e. typical ozonation by-products) in order to simulate water that had been subjected to ozonation prior to filtration. Using fresh GAC, total removals of geosmin ranged from 76 to 100% and total MIB removals ranged from 47% to 100%. The exhausted GAC initially removed less geosmin and MIB but removals increased over time. Overall the results of these experiments are encouraging for the use of biofiltration following ozonation as a means of geosmin and MIB removal. These results provide important information with respect to the role biofilters play during their startup phase in the reduction of these particular compounds. In addition, the results demonstrate the potential biofilters have in responding to transient geosmin and MIB episodes.     

灰水处理及回用技术研究综述

由于灰水污染物浓度较低,水量占比大,约占家庭生活污水总量的75%左右,容易实现灰水处理与再生利用,因此研究灰水回用技术具有重要的现实意义。综述了不同地区的灰水水量和水质特点,总结分析了过滤、人工湿地、膜生物反应器等不同处理技术对灰水的处理效果。结果表明,灰水的产生量受生活方式、气候条件等因素影响。灰水中的污染物主要与使用的洗涤剂类型有关,并受到其他家庭活动的影响。人工湿地和过滤技术能有效去除灰水中的污染物,是较适宜的灰水处理技术。当前国内外更多的关注了单项处理技术对灰水中污染物的去除效果,未来应该结合灰水的水量水质特点研发针对不同回用目标的灰水处理组合工艺,研究灰水中微污染物去除技术,确保公众健康。     

Water circuit closure with membrane technology in the pulp and paper industry.

In this study, membrane filtration as an internal purification method, "the kidney", in the pulp and paper industry is discussed. Membrane filtration is economically competitive and a very versatile process. It can be used to remove the enriched organic and/or inorganic loads either partially or totally from, for example, the mechanical pulping and paper making water circuits and it can be applied to various points within the process. With the so-called shear enhanced membrane modules very high fluxes, in ultrafiltration about 400 L/(m2h) and in nanofiltration fluxes almost 200 L/(m2h), have been obtained. Depending on the membrane, suspended solids (microfiltration), polysaccharides, extractives and high molar mass lignous substances (ultrafiltration) and multivalent salts (nanofiltration) can be removed. Ultrafiltration permeate can well be used in paper machine showers to replace fresh water. The quality of the nanofiltration permeate is significantly higher than that of ultrafiltration. The membrane processes can be enhanced by various pre-treatment techniques to produce higher permeate fluxes and to eliminate membrane fouling. Such pre-treatment methods are, e.g., chemical treatment, ozonation and biological treatment. The most cost-effective processes were chemical flocculation, pH adjustment and thermophilic aerobic biological treatment.     

Removal of cyanobacterial metabolites through wastewater treatment plant filters

Wastewaters have the potential to proliferate excessive numbers of cyanobacteria due to high nutrient levels. This could translate to the production of metabolites, such as the saxitoxins, geosmin and 2-methylisoborneol (MIB), which can impair the quality of wastewater destined for re-use. Biological sand filtration was assessed for its ability to remove these metabolites from a wastewater. Results indicated that the sand filter was incapable of effectively removing the saxitoxins and in some instances, the effluent of the sand filter displayed greater toxicity than the influent. Conversely, the sand filter was able to effectively remove geosmin and MIB, with removal attributed to biodegradation. Granular activated carbon was employed as an alternative filter medium to remove the saxitoxins. Results showed similar removals to previous drinking water studies, where efficient removals were initially observed, followed by a decrease in the removal; a consequence of the presence of competing organics which reduced adsorption of the saxitoxins.     

含沙量对水体耗氧有机污染物降解耗氧影响

在泥沙存在情况下，水体中的耗氧有机污染物的降解耗氧规律与清水中有很大的差异。从水体耗氧有机物降解反应动力学和溶解氧反应动力学方程出发，考虑泥沙对耗氧有机污染物降解的影响，得出了耗氧有机物降解过程耗氧量随时间变化表达式。通过室内实验研究了含沙量对耗氧有机污染物的耗氧规律的影响，利用耗氧量随时间表达式对实验数据进行分析，得出了泥沙影响下的耗氧有机污染物耗氧速率常数与含沙量的一般规律。结果表明，泥沙对耗氧有机污染物降解耗氧过程符合一级动力学反应，且耗氧速率常数随含沙量的增大而增大，由泥沙存在引起的溶解氧衰减速率常数与含沙量之间存在非线线的函数关系。     

Review on the fate of organic micropollutants in wastewater treatment and water reuse with membranes

A brief review of the fate of micropollutants in membrane-based wastewater treatment due to sorption, stripping, biological degradation/transformation and membrane separation is discussed, to give an overview of these technologies due to the growing importance for water reuse purposes. Compared with conventional activated sludge treatment (CAS) micropollutant removal in membrane bioreactor (MBR) is slightly improved due to complete suspended solids removal and increased sludge age. For discharge to sensitive receiving waters advanced treatment, such as post-ozonation or activated carbon adsorption, is recommended. In water reuse plants nanofiltration (NF) and reverse osmosis (RO) efficiently reject micropollutants due to size exclusions as well as electrostatic and hydrophobic effects reaching potable quality. To remove micropollutants fully, additionally post-ozone or the addition of powdered activated carbon (PAC) have to be applied, which in parallel also reduce NDMA precursors. The concentrate has to be treated if disposed to sensitive receiving waters due to its high micropollutant concentration and ecotoxicity potential. The present review summarizes principles and capabilities for the most important membrane-based applications for wastewater treatment, i.e. porous membranes in MBRs (micro- or ultrafiltration) and dense membrane applications (NF and RO) for water reuse.