农药污染地下水的微生物治理及含水层渗透性变化研究

采用了从农药厂阿特拉津生产车间排污口污泥中分离出的菌种AT菌 ,进行了农药阿特拉津污染地下水微生物治理的模拟实验研究 ,在实验条件 (T =10℃ ,pH =7.5 )与野外含水层的条件基本一致情况下 ,难于生物降解的污染质阿特拉津的一次投菌降解率可达 3 1.0 8% ;设计了两种有效细菌的投放方式以模拟野外条件下的菌种投加条件。另外 ,AT菌的作用会造成被治理含水层的渗透性能降低 ,两种投菌方式下 ,实验后含水层的渗透系数分别下降 60 .5 4%和 3 4 5 6%。清水冲洗 10d的渗透性恢复率分别为 48.96%及 81.3 6% ,说明清水渗透恢复的方法效果明显     

秸秆固定化石油降解菌降解原油的初步研究

用秸秆做载体固定嗜碱芽孢杆菌(Bacillus alcalophilus SG)降解原油,其原油去除率为73.88%,高于单纯投加菌液或者菌液与秸秆的混合物的原油去除率.秸秆的最佳投加量(干重)为25.0 g/L,最佳固定化时间为30 h.用预处理过的秸秆固定SG,降低了固定化SG的原油去除率.在固定化培养基中添加无机盐离子,促进了固定化SG对原油的降解.不同初始pH的原油培养基在固定化SG降解原油的过程中逐渐呈中性或偏碱性.固定化SG在pH 6.0～10.0时对原油均有不错的降粘能力.     

常熟河网区水污染物总量控制研究

基于常熟河网原型调水实验和水功能区划，建立了感潮地区河网水量水质模型，对常熟河道水质降解系数及水环境容量进行了计算，并按照点源和面源对区域内污染源进行统计，在此基础上进行了常熟河网水污染物总量控制值和现状削减量的计算，为该地区的水污染防控提供了科学依据。     

Human exposure to dioxins through the diet in Catalonia,Spain: carcinogenic and non-carcinogenic risk

The main objectives of this study were to estimate the dietary intake of dioxins by the population of Catalonia, Spain, to determine which food groups showed the greatest contribution to this intake, and to assess the health risks potentially associated with the dietary dioxin intake. From June to August 2000, food samples were randomly acquired in seven cities of Catalonia. Dioxin concentrations were determined in 108 samples belonging to the following groups: vegetables, fruits, pulses, cereals, fish and shellfish, meats and meat products, eggs, milk and dairy products, and oils and fats. Estimates of average daily food consumption were obtained from recent studies. Total dietary intake of dioxins for the general population of Catalonia was estimated to be 95.4 pg WHO-TEQ/day (78.4 pg I-TEQ/day), with fish and shellfish (31%), diary products (25%), cereals (14%) and meat (13%) showing the greatest percentages of contribution to dioxin intake. The contribution of all the rest of food groups to the total dietary intake was under 20%. The non-carcinogenic risk index of dioxin intake through the diet was in the range 0.34-1.36, while the carcinogenic risk level was 1,360 excess cancer over a lifetime of 70 years. Our results corroborate the decreasing tendency in dietary intake of dioxins found in recent studies (2000-2001) from various countries.     

Electrochemical degradation of chlorophenoxy and chlorobenzoic herbicides in acidic aqueous medium by the peroxi-coagulation method

The degradation of 4-chlorophenoxyacetic acid (4-CPA), 4-chloro-2-methylphenoxyacetic acid (MCPA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) as chlorophenoxy herbicides, as well as of 3,6-dichloro-2-methoxybenzoic acid (dicamba) as chlorobenzoic herbicide, has been studied by peroxi-coagulation. This electrochemical method yields a very effective depollution of all compounds in acidic aqueous medium of pH 3.0 working under pH regulation, since they are oxidized with hydroxyl radicals produced from Fenton's reaction between Fe(2+) and H(2)O(2) generated by the corresponding Fe anode and O(2)-diffusion cathode. Their products can then be removed by mineralization or coagulation with the Fe(OH)(3) precipitate formed. Both degradative paths compete at low currents, but coagulation predominates at high currents. The peroxi-coagulation process of dicamba at I>or=300 mA leads to more than 90% of coagulation, being much more efficient than its comparative electro-Fenton treatment with a Pt anode and 1 mM Fe(2+), where only mineralization takes place. For the chlorophenoxy compounds, electro-Fenton gives a slightly lower depollution than peroxi-coagulation, because more easily oxidable products are produced. Oxidation of chlorinated products during peroxi-coagulation is accompanied by the release of chloride ion to the solution. The efficiency of this method decreases with increasing electrolysis time and current. The decay of all herbicides follows a pseudo-first-order reaction, with a similar constant rate for 4-CPA, MCPA, 2,4-D and 2,4,5-T, and a higher value for dicamba.     

同步硝化反硝化生物脱氮技术研究

讨论了影响同步硝化反硝化反应的各参数，并进行了单因素实验与正交实验，获得了同步硝化反硝化生物脱氮工艺运行的最佳条件：DO浓度控制在0．5～2mg／L，COD浓度为600～800mg／L，混合液悬浮固体（MLSS）为5000mg/L，pH值在8．0左右，反应时间为6h。在此条件下，氨氮及COD的去除率都较高，分别达85％和95％，总氮去除率为68．5％。     

同步硝化反硝化生物脱氮技术研究

讨论了影响同步硝化反硝化反应的各参数,并进行了单因素实验与正交实验,获得了同步硝化反硝化生物脱氮工艺运行的最佳条件:DO浓度控制在0.5～2 mg/L,COD浓度为600～800mg/L,混合液悬浮固体(MLSS)为5000 mg/L,pH值在8.0左右,反应时间为6 h.在此条件下,氨氮及COD的去除率都较高,分别达85%和95%,总氮去除率为68 5%.     

造纸中段废水与生活污水合并深度处理工艺

采用水解酸化 CAST 混凝 复合滤池与水解酸化 接触氧化 混凝 复合滤池2种组合工艺对造纸中段废水与生活污水进行合并处理对照试验.结果表明,两种工艺都是切实可行的,二级出水均可达到<污水综合排放标准>(GB8978-1996)二级标准,深度处理出水可达中水水质要求.其中以水解酸化 CAST 混凝 复合滤池组合工艺效果最好.     

Biochar as low-cost sorbent of volatile fuel organic compounds: potential application to water remediation

Pyrolysis of waste materials to produce biochar is an excellent and suitable alternative supporting a circular bio-based economy. One of the properties attributed to biochar is the capacity for sorbing organic contaminants, which is determined by its composition and physicochemical characteristics. In this study, the capacity of waste-derived biochar to retain volatile fuel organic compounds (benzene, toluene, ethylbenzene and xylene (BTEX) and fuel oxygenates (FO)) from artificially contaminated water was assessed using batch-based sorption experiments. Additionally, the sorption isotherms were established. The results showed significant differences between BTEX and FO sorption on biochar, being the most hydrophobic and non-polar contaminants those showing the highest retention. Furthermore, the sorption process reflected a multilayer behaviour and a relatively high sorption capacity of the biochar materials. Langmuir and Freundlich models were adequate to describe the experimental results and to detect general differences in the sorption behaviour of volatile fuel organic compounds. It was also observed that the feedstock material and biochar pyrolysis conditions had a significant influence in the sorption process. The highest sorption capacity was found in biochars produced at high temperature (>?400 °C) and thus rich in aromatic C, such as eucalyptus and corn cob biochars. Overall, waste-derived biochar offers a viable alternative to be used in the remediation of volatile fuel organic compounds from water due to its high sorption capacity.

     

Microplastic distribution in surface sediments along the Spanish Mediterranean continental shelf

Environmental Science and Pollution Research - Microplastics (MPs) are widely recognised as a contaminant of emerging concern in the marine environment. This work provides original data of the...