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681.
Model reactor for photocatalytic degradation of persistent chemicals in ponds and waste water 总被引:10,自引:0,他引:10
A laboratory scale flow-through model reactor for the degradation of persistent chemicals using titanium dioxide (TiO2) as photocatalyst immobilized on glass beads is presented. In the test system with a volume of 18 L contaminated water is pumped to the upper part of the floating reactor and flows over the coated beads which are exposed to UV-radiation. The degradation of two dyes of different persistance was investigated. Primary degradation of methylene blue did not fit a first order kinetic due to coincident adsorption onto the photocatalyst and direct photolysis, resulting in a half-life of 6 h. A filtrate of a green algae suspension accelerated the colour removal. In contrast, reactive red 2 was degraded only by photocatalysis; neither adsorption nor direct photolysis led to a colour removal. The course of primary degradation followed a first order kinetic with a half-life of 18 h and a rate constant of 0.04 h−1. Analysis of the degradation products indicated mineralization by detection of NO2− and NO3−, accompanied by a decrease of pH and an increase of conductivity. A successful adaptation of the model reactor (scale 1:10) to dimensions required for surface waters and waste water treatment plants would be a costefficient and environmentally sustainable application of photocatalysis for the treatment of industrially polluted water and could be of relevance for third world contries, particularly those favoured by high solar radiation. 相似文献
682.
Adama Ndao Lalit R Kumar Rajeshwar. D. Tyagi Jose Valéro 《Journal of environmental science and health. Part. B》2020,55(2):115-126
AbstractThe aim of this study was to produce Bacillus thuringiensis-based biopesticide using starch-producing industry wastewater (SIW) fortified with soybean medium and optimize the formulated product using different adjuvants. This study was necessary as low endotoxin concentration is obtained in formulated biopesticide when SIW alone is used as fermentation medium. The fermentation runs were conducted using SIW alone and SIW fortified with 25% soybean (w/v) medium in 2000?L and 150?L bioreactor, respectively. SIW supplemented with soybean medium showed an increase in cell count (from 1.95?×?108 to 1.65?×?109 CFU mL–1), spore synthesis (from 1.5?×?108 to 1.35?×?109 CFU mL–1) and endotoxin concentration (from 436 to 1170?μg mL–1) when compared to SIW medium alone. The fermented broth was concentrated using continuous centrifugation and adjuvants were added for biopesticide formulation in order to enhance its resistance against UV rays and rainfastness. Entomotoxicity of the formulation produced using fermented broth of SIW fortified with soybean (38,000?IU μL–1) was higher than that obtained by SIW medium alone (21,000?IU μL–1), commercial biopesticide Foray 76B (20,000?IU μL–1) and Btk sander’s (12,500?IU μL–1). 相似文献
683.
684.
Jean-Paul Schwitzguébel Hailong Wang 《Environmental science and pollution research international》2007,14(7):446-544
Goal, Scope and Background Aquaculture activities are well known to be the major contributor to the increasing level of organic waste and toxic compounds
in the aquaculture industry. Along with the development of intensive aquaculture in China, concerns are evoked about the possible
effects of everincreasing aquaculture waste both on productivity inside the aquaculture system and on the ambient aquatic
ecosystem. Therefore, it is apparent that appropriate waste treatment processes are needed for sustaining aquaculture development.
This review aims at identifying the current status of aquaculture and aquaculture waste production in China.
Main Features China is the world’s largest fishery nation in terms of total seafood production volume, a position it has maintained continuously
since 1990. Freshwater aquaculture is a major part of the Chinese fishery industry. Marine aquaculture in China consists of
both land-based and offshore aquaculture, with the latter mostly operated in shallow seas, mud flats and protected bays. The
environmental impacts of aquaculture are also striking.
Results Case studies on pollution hot spots caused by aquaculture have been introduced. The quality and quantity of waste from aquaculture
depends mainly on culture system characteristics and the choice of species, but also on feed quality and management. Wastewater
without treatment, if continuously discharged into the aquatic environment, could result in remarkable elevation of the total
organic matter contents and cause considerable economy lost. Waste treatments can be mainly classified into three categories:
physical, chemical and biological methods.
Discussion The environmental impacts of different aquaculture species are not the same. New waste treatments are introduced as references
for the potential development of the waste treatment system in China. The most appropriate waste treatment system for each
site should be selected according to the sites’ conditions and financial status as well as by weighing the advantages and
disadvantages of each system. Strategies and perspectives for sustainable aquaculture development are proposed, with the emphasis
on environmental protection.
Conclusions Negative effects of waste from aquaculture to aquatic environment are increasingly recognized, though they were just a small
proportion to land-based pollutants. Properly planned use of aquaculture waste alleviates water pollution problems and not
only conserves valuable water resources but also takes advantage of the nutrients contained in effluent. It is highly demanding
to develop sustainable aquaculture which keeps stocking density and pollution loadings under environmental capacity.
Recommendations and Perspectives The traditional procedures for aquaculture waste treatment, mainly based on physical and chemical means, should be overcome
by more site-specific approaches, taking into account the characteristics and resistibility of the aquatic environment. Further
research needs to improve or optimize the current methods of wastewater treatment and reuse. Proposed new treatment technology
should evaluate their feasibility at a larger scale for practical application.
ESS-Submission Editor: Dr. Ding Wang (wangd@ihb.ac.cn) 相似文献
685.
Fenton试剂在乳化液废水处理中的应用 总被引:1,自引:0,他引:1
用Fenton试剂处理乳化液废水,通过试剂在不同配比条件下对废水处理效果的实验比较,选择了最佳反应条件,废水处理后的COD测量结果表明,反应处理在实验室可行。 相似文献
686.
聚苯乙烯基离子交换纤维去除铅离子的应用研究 总被引:5,自引:0,他引:5
聚苯乙烯其离子交换纤维是一种理想的离子交换材料。它的特殊的物理形态决定它对一些有害气体如铅烟、颗粒铅等具有很好的净化作用,铅烟净化效率可达80%;对水溶液中毒性铅离子去除率可达86%。该纤维可做为治理毒性铅离子的材料。 相似文献
687.
针对生物质固体废物量大面广,具有污染和资源利用双重特性,厌氧发酵能源化可促进其污染控制,且过程中部分有机成分在微生物作用下转化成腐殖质(HS).通过分析厌氧发酵过程中HS转化规律、HS结构特征与氧化还原性能、腐殖质还原菌与产甲烷菌活性、产CH4效率之间的响应关系和作用机制研究进展,总结凝练出生物质厌氧发酵系统内HS对CH4的调控原理,为减少厌氧发酵系统内HS对产CH4途径的抑制作用,提高发酵效率的技术研究提供理论支撑. 相似文献
688.
Chemical waste compositions are important for municipal solid waste management, as they determine the pollution potentials from different waste strategies. A representative dataset for chemical characteristics of individual waste fractions is frequently required to assess chemical waste composition, but it is usually reported in developed countries and not in developing countries. In this study, a dataset for Chinese waste was established through careful data screening and assessment, named as CN dataset. Meanwhile, a dataset for Danish waste (DK dataset) was also summarized based on previous studies. In order to quantitatively evaluate the reliabilities of CN and DK datasets, the chemical waste compositions in four Chinese cities were estimated by utilizing both of them, respectively. It is indicated that the usage of CN datasets led to significantly lower discrepancies from the actual values based on laboratory analysis in most cases. Within the datasets, the moisture contents of food waste, paper, textiles, and plastics, the carbon content of food waste, as well as the oxygen content of plastics would induce significant divergences, which should be paid special attention when gathering the information. In addition, the fractional waste compositions in China showed similar features with other developing countries but differ significantly with developed countries. Thus the above-mentioned conclusions could also be true in other developing countries. 相似文献
689.
为研究城市生活垃圾填埋场中抗生素的残留及其浓度特征,采集上海市老港填埋场中固体废弃物和渗滤液样本,采用超高效液相色谱三重四级杆质谱联用技术(UPLC-3Q-MS)检测抗生素浓度.结果显示,固体废弃物和渗滤液中四环素类、磺胺类、喹诺酮类、大环内脂类及β-内酰胺类抗生素的检出浓度范围分别为0.1~4.9μg·kg~(-1),nd~3245.0 ng·L~(-1)、nd~16.3μg·kg~(-1),nd~1360.0 ng·L~(-1)、0.2~367.5μg·kg~(-1),nd~6950.0ng·L~(-1)、LOQ~8.4μg·kg~(-1),0.3~9450.0 ng·L~(-1)及nd~2.8μg·kg~(-1),nd~293.5 ng·L~(-1).抗生素浓度在垃圾填埋场中的分布存在时空差异,填埋场1.5 m处固体废弃物中抗生素的浓度高于0.5 m处,新鲜渗滤液中抗生素浓度大于老龄渗滤液.研究结果为可今后垃圾填埋场中残留抗生素的治理提供理论依据. 相似文献
690.
包装废弃物添加脱氯半焦制备SRF的热解及动力学特性 总被引:1,自引:0,他引:1
利用热重红外分析仪(TG-FTIR)对包装废弃物添加了4种不同比例脱氯半焦制备而成的固体衍生燃料(SRF)的热解特性及热反应动力学进行了研究分析.研究发现,4种燃料热解过程主要包括4个阶段,其中300~400℃和400~500℃为两个主要失重阶段.前一阶段,SRF-1失重显著高于SRF-2、SRF-3和SRF-4,而后一阶段失重分别呈2、3、4倍增加.4种燃料热解残余量的顺序为SRF-4SRF-3SRF-2SRF-1,即添加了脱氯半焦的燃料热解程度越高.FTIR分析表明,添加了脱氯半焦的SRF燃料第三失重峰处不产生氯代烃.随脱氯半焦添加量的增加,第二失重峰CO2产生的浓度减少;第三失重峰CH4析出浓度增加;第四失重峰CO2析出的浓度增加.采用DEAM分布活化能法得到,转化率α0.3时,SRF-2和SRF-3的活化能均高于SRF-1的活化能,0.3α0.9时(α为0.6时除外),SRF-2、SRF-3和SRF-4 3种燃料的活化能低于SRF-1,且SRF-1的活化能呈升高的趋势,而其他3种燃料呈相反趋势.脱氯半焦的添加有利于SRF燃料的热解. 相似文献