EMMC process for combined removal of organics, nitrogen and an odor producing substance

In order to improve the process performance regarding the removal of organics, nitrogen, and an odor-causing compound (sulfide) contained in domestic wastewater, an entrapped-mixed-microbial cell (EMMC) with and without humic substances for both fixed and moving carrier reactors and conventional suspended growth culture (i.e. conventional activated sludge process) were investigated simultaneously. Both synthetic (simulated to the organics concentration of general domestic sewage) and actual domestic wastewater were investigated under operational conditions of 12 h of hydraulic retention time (HRT) with 1 h of aeration and 1 h of non-aeration, and 6 h of HRT with continuous aeration, at a room temperature of 25 +/- 2 degrees C. It was found that entrapping humic substances in the EMMC carriers had no impact on the removal of organics, nitrogen, and the odor-producing compound. Additionally, the performance of the EMMC moving carrier system for the removal of these pollutants is similar to that of the EMMC fixed carrier system. In general, the EMMC associated systems which provide high solids retention time achieve a better removal of chemical oxygen demand (COD), nitrogen, and the odor-producing substance than the suspended growth system for both HRTs of 6 h (continuous aeration) and 12 h (1 h of aeration and 1 h of non-aeration). Both the fixed and moving carrier EMMC processes, therefore, have the potential for improvement or replacement of the existing conventional activated sludge process with regard to improving the effluent qualities (such as COD, nitrogen and odor-producing compound) for reuse/disposal.     

Analysis of spatial and temporal changes of vegetation cover and its driving forces in the Huainan mining area

Environmental Science and Pollution Research - The Huainan mining area is rich in coal resources and has sparse vegetation and many collapsed waterways. Large-scale and long-term underground coal...     

延边地区水稻稳产高产施肥体系的探讨

采用二次饱和D-最优设计,建立了有机肥、氮肥、磷肥和钾肥配合施用对水稻产量影响的数学模型.研究表明有机肥施用量的过多或过少均使水稻产量下降,化肥的施用也有相似的影响;有机肥与氮肥、磷肥、钾肥只有施用量在适宜的范围内,交互作用较大,产量最高.提出了延边地区水稻获得稳产、高产的施肥体系.     

Geostatistical analysis and risk assessment on soil total nitrogen and total soil phosphorus in the Dongting Lake plain area, China

Nonpoint-source pollution and water body eutrophication have become increasing concerns for scientists and policymakers. Nitrogen and phosphorus affect environmental pollution, especially lake eutrophication. To assess the environmental risk of soil total nitrogen (TN) and total phosphorus (TP) pollution, a typical ecological unit of Dongting Lake plain was selected as the experimental site. To verify the stationary of the data, a moving windows technique was adopted. Our results showed that Box-Cox transformation achieved normality in the data set and dampened the effect of outliers. The best theoretical model for semivariogram of TN and TP was a spherical model. The ordinary kriging estimates of TN and TP concentrations were mapped. The integrative comparisons of semivariogram parameters with different trends to the kriging prediction errors of TN and TP indicated that the two-order trend is preferable. Kriging SDs provided valuable information that will increase the accuracy of TN and TP mapping. The probability kriging method is useful to assess the risk of N and P pollution by providing the conditional probability of N and P concentrations exceeding the threshold concentrations of 3.2 and 1.05 g/kg, respectively. The probability distribution of TN and TP at different levels will be helpful to conduct risk assessment, optimize fertilization, and control the pollution of N and P.     

乌江流域县域社会经济发展的综合评价与分析

在简要阐述了县域社会经济发展综合评价原则的基础上,建立了悬域社会经济发展综合评价的指标体系,利用层次分析法确定了各评价因子的权重。接着以乌江流域为例,对流域内４０个县域的社会经济发展水平进行了定量评价,指出了流域内县域社会经济发展中存在的问题,并提出了相应的对策,旨在为促进乌江流域的县域社会经济协调发展提供某些科学依据。     

Mercury uptake by Paspalum distichum L. in relation to the mercury distribution pattern in rhizosphere soil

Environmental Science and Pollution Research - Paspalum distichum L. was tested to evaluate their phytoremediation capacity for Hg contaminated soil through analyzing the dissipation of Hg in soil...     

混凝沉淀-二氧化氯氧化法处理印染废水

介绍了混凝沉淀－ＣｌＯ２氧化法处理印染废水的反应机理,工艺流程,处理效果及经济效益分析。在２个工厂的实际应用表明,该法工艺简单,操作方便,投资少,效果好。     

Shell shape variation in populations of Mytilus chilensis (Hupe 1854) from southern Chile: a geometric morphometric approach

The pattern of shell shape variation in populations of the mussel, Mytilus chilensis (Hupe 1854) from Southern Chile was analyzed as a function of sample origin (cultivated vs. wild) and latitude, using standard tools of geometric morphometrics for landmark data. Additionally, posterior adductor muscle index (PAMI), Freeman condition index and shell thickness were measured in each sample. Highly significant differences in shell shape components were found among mussel populations. These differences are related to the origin of samples (expansion of the posterior adductor muscle scar, elongation of the lateral ligament and of the ventral umbo position in non-cultivated samples) and to latitude (more elongated shells and more extended posterior adductor muscle scar in most southern samples when compared with the northernmost ones). PAMI and shell thickness were statistically higher in wild population, and Freeman condition index was higher in cultivated shells. It is suggested that in wild populations of M. chilensis, the mussels may face higher predator pressures and other environmental stress factors. Consequently, individuals may be using higher energy fraction to reinforce shells and to promote adductor muscle growth at the expense of somatic growth. In contrast, individuals found in calm aquaculture environments are relatively protected from predators and use most of their assimilated energy in somatic growth. In turn, this growth depends on changes that covariate with shell morphology.     

Modulation of hepatic and intestinal glutathione S-transferases and other antioxidant enzymes by dietary lipids in streptozotocin diabetic rats

Antioxidant enzymes in liver and small intestine were investigated using control and streptozotocin diabetic rats fed diets with 5% olive, sunflower or fish oil for five weeks. In liver, Glutathione Peroxidase and Superoxide Dismutase decreased and in intestine Glutathione-S-transferase (GST) increased by diabetes. In isolated jejunum and ileum, this increase in GST activity was due to an increase in GST-alpha and -mu isoenzymes in jejunum and GST-alpha, mu and -pi in ileum. Since GST plays an important role in protecting tissues from oxidative damage, our results highlight the role of the intestine against free radicals in physiological or pathological situations.