固相萃取-UPLC-MS/MS法测定环境水体中多种抗生素

采用固相萃取-超高效液相色谱串联质谱法测定环境水样中25种磺胺类和喹诺酮类抗生素,通过优化试验条件,使方法在2.00μg/L～200μg/L范围内线性良好,方法检出限为1.01ng/L～2.85ng/L,7次测定结果的RSD为2.3%～8.0%。将该方法用于自来水和地表水测定,结果均为未检出,高、低质量浓度水平的加标回收率为61.2%～102%。     

HPLC-三重四级杆质谱法测定医疗废水中抗生素残留

采用固相萃取/高效液相色谱-三重四级杆质谱法同时测定医疗废水中的20种超痕量抗生素残留,通过优化试验条件,使方法在100μg/L～100μg/L范围内线性良好,方法检出限为024ng/L～122ng/L。空白水样和实际水样3个质量浓度水平的加标回收率分别为80.2%～108%和75.8%～114%,6次测定结果的RSD分别为2.4%～8.4%和1.7%～8.1%。将该方法用于测定重庆市2家三甲医院医疗废水中的超痕量抗生素残留,结果有11种抗生素检出,其余均为未检出。     

Effects of long-term amendment of organic manure and nitrogen fertilizer on nitrous oxide emission in a sandy loam soil

To understand the effects of long-term amendment of organic manure and N fertilizer on N2O emission in the North China Plain, a laboratory incubation at different temperatures and soil moistures were carried out using soils treated with organic manure （OM）, half organic manure plus half fertilizer N （HOM）, fertilizer NPK （NPK）, fertilizer NP （NP）, fertilizer NK （NK）, fertilizer PK （NK） and control （CK） since 1989. Cumulative N2O emission in OM soil during the 17 d incubation period was slightly higher than in NPK soil under optimum nitrification conditions （25℃ and 60% water-filled pore space, WFPS）, but more than twice under the optimum denitrification conditions （35℃ and 90% WFPS）. N2O produced by denitrification was 2.1-2.3 times greater than that by nitrification in OM and HOM soils, but only 1.5 times greater in NPK and NP soils. These results implied that the long-term amendment of organic manure could significantly increase the N2O emission via denitrification in OM soil as compared to NPK soil. This is quite different from field measurement between OM soil and NPK soil. Substantial inhibition of the formation of anaerobic environment for denitrification in field might result in no marked difference in N2O emission between OM and NPK soils. This is due in part to more rapid oxygen diffusion in coarse textured soils than consumption by aerobic microbes until WFPS was 75% and to low easily decomposed organic C of organic manure. This finding suggested that addition of organic manure in the tested sandy loam might be a good management option since it seldom caused a burst of N2O emission but sequestered atmospheric C and maintained efficiently applied N in soil.     

Effect of sulfate on the methanogenic activity of a bacterial culture from a brewery wastewater during glucose degradation

The maximum specific methanogenic activity （SMA） of a sludge originating from a brewery wastewater treatment plant on the degradation of glucose was investigated at various levels of sulfate on a specific loading basis. Batch experiments were conducted in serum bottles at pH 7 and 35℃. A comparison of the values indicates that the SMA of this mixed culture was increased and reached its highest level of 0.128 g CH4 gas COD/（g VSS.d） when biomass was in contact with sulfate at a ratio of 1：0.114 by weight.     

Anaerobic tapered fluidized bed reactor for starch wastewater treatment and modeling using multilayer perceptron neural network

Anaerobic treatability of synthetic sago wastewater was investigated in a laboratory anaerobic tapered fluidized bed reactor(ATFBR) with a mesoporous granular activated carbon(GAC)as a support material.The experimental protocol was defined to examine the effect of the maximum organic loading rate(OLR),hydraulic retention time(HRT),the efficiency of the reactor and to report on its steady- state performance.The reactor was subjected to a steady-state operation over a range of OLR up to 85.44 kg COD/(m~3.d).The COD removal efficiency was found to be 92% in the reactor while the biogas produced in the digester reached 25.38 m~3/(m~3·d) of the reactor. With the increase of OLR from 83.7 kg COD/(m~3.d),the COD removal efficiency decreased.Also an artificial neural network(ANN) model using multilayer perceptron(MLP)has been developed for a system of two input variable and five output dependent variables. For the training of the input-output data,the experimental values obtained have been used.The output parameters predicted have been found to be much closer to the corresponding experimental ones and the model was validated for 30% of the untrained data.The mean square error(MSE)was found to be only 0.0146.     

Irrigation Water Allocation Using an Inexact Two‐Stage Quadratic Programming with Fuzzy Input under Climate Change

Agricultural irrigation accounts for nearly 70% of the total water use around the world. Uncertainties and climate change together exacerbate the complexity of optimal allocation of water resources for irrigation. An interval‐fuzzy two‐stage stochastic quadratic programming model is developed for determining the plans for water allocation for irrigation with maximum benefits. The model is shown to be applicable when inputs are expressed as discrete, fuzzy or random. In order to reflect the effect of marginal utility on benefit and cost, the model can also deal with nonlinearities in the objective function. Results from applying the model to a case study in the middle reaches of the Heihe River basin, China, show schemes for water allocation for irrigation of different crops in every month of the crop growth period under various flow levels are effective for achieving high economic benefits. Different climate change scenarios are used to analyze the impact of changing water requirement and water availability on irrigation water allocation. The proposed model can aid the decision maker in formulating desired irrigation water management policies in the wake of uncertainties and changing environment.     

Testing and Improving Temperature Thresholds for Snow and Rain Prediction in the Western United States

The phase of precipitation at the land surface is critical to determine the timing and amount of water available for hydrological and ecological systems. However, there are few techniques to directly observe the precipitation phase and many prediction tools apply a single temperature threshold (e.g., 0°C) to determine phase. In this paper, we asked two questions: (1) what is the accuracy of default and station optimized daily temperature thresholds for predicting precipitation phase and (2) what are the regions and conditions in which typical temperature‐based precipitation phase predictions are most suited. We developed a ground truth dataset of rain vs. snow using an expert decision‐making system based on precipitation, snow depth, and snow water equivalent observations. This dataset was used to evaluate the accuracy of three temperature‐threshold‐based techniques of phase classification. Optimizing the temperature threshold improved the prediction of precipitation phase by 34% compared to using 0°C threshold. Developing a temperature threshold based on station elevation improved the error by 12% compared with using the 0°C temperature threshold. We also found the probability of snow as a function of temperature differed among ecoregions, which suggests a varied response to future climate change. These results highlight a current weakness in our ability to predict the effects of regional warming that could have uneven impacts on water and ecological resources.     

微量金属元素及其配合物对厨余垃圾甲烷发酵的影响

生物可利用的微量金属元素不仅能够保证污染物以最大的速率转化,而且还可以使某些特殊的转化得以发生,并提高微生物对有毒污染物质的耐受能力。在研究厨余垃圾总固体浓度(total solid, TS)、接种量和C/N比对厨余垃圾厌氧发酵影响的基础上,重点探讨微量金属元素钴及其配合物丝氨酸对厨余垃圾厌氧发酵甲烷产量及关键酶含量的影响。结果表明,当TS为0.5%、接种污泥量为100 mL/L和C/N比为20∶1时,厨余垃圾厌氧发酵的甲烷产率较高,为367 mL/g COD;添加2 μmol/L的微量金属元素钴-配合物丝氨酸时,甲烷产率则提高到432 mL/g COD,相应地,辅酶M的含量由空白实验的41.21 μmol/g VSS提高到54.64 μmol/g VSS,辅酶F₄₂₀的含量由0.31 μmol/g VSS提高到0.48 μmol/g VSS。     

厌氧序批式反应器内挥发性脂肪酸积累特性研究

小试规模的厌氧序批式反应器（ASBR）,通过人工配水,研究了启动3个月时间以及一个运行周期内反应器内挥发性脂肪酸（VFA）的积累情况,并通过分析期间产甲烷活性的变化说明了控制VFA积累的重要性。经过近120 d的运行,乙酸和丙酸的最大比产甲烷活性分别提高了1.8和2.2倍,说明反应器的启动过程即是微生物群落的优化和选择的过程,ASBR的抗冲击的能力较强说明随启动的进行和种群的优化,活性污泥凝聚性能增强,对VFA的降解能力增强。     

联合生物法处理炼油厂含油污泥的研究

大港石化公司采用联合生物法处理含油污泥,对使用好氧、厌氧工艺处理含油污泥的结果进行了探讨。实验结果表明:先进行好氧处理然后脱水再进行厌氧堆肥工艺处理含油污泥,除油率达到97.6%,除磷、钾的指标低于《城镇垃圾农用控制标准》(GB8172-87)的要求外,其他指标均符合该标准要求,且避免了二次污染。