More than 80% of sewage sludge (SS) produced in Iran is landfilled with high environmental impact. The chemical properties of SS produced from wastewater plants of cites of Arak, Isfahan, Kermanshah, Rasht, Saveh, Shiraz, Sanandaj, Tehran, Takestan, and Toyserkan were studied to assess the potential beneficial effects of their application to agricultural soil as sustainable SS management. The pH and EC values, total content and water-soluble concentration of nutrients and heavy metals, their water-extractable pools were determined, and their speciation was done through the NICA–Donnan model using the Visual MINTEQ software. Relatively high contents of N, P, and physiologically active cations indicated potential beneficial effects of SS for land application in the agro-ecosystems, whereas the heavy metal content depended on the SS production site, with higher levels found in the SS of the Arak and Saveh wastewater treatment plants. The pH value was the main factor controlling the metal speciation, with Cu and Pb having the highest affinity for the organic matter, and Zn and Mn being mainly present as free ions or inorganic species. Results showed that SS from different locations in Iran differed in their main chemical properties and elemental composition and that speciation analysis could be used to predict potential beneficial and harmful effects of SS, particularly upon the modeling of metal–organic complexes by the NICA–Donnan approach. Globally, our results confirmed that while the SS produced in Iran has potential suitable chemical properties for use in agriculture, their heavy metals load should not be ignored.
Mathematical Geosciences - Characterization of field-scale reservoir connectivity is critical for production optimization and field development planning. The information content of the data... 相似文献
The bioremediation of soil contaminated with the herbicide 2,4‐dichlorophenoxy acetic acid has been studied applying the bacterium Ralstonia eutropha. The effects of temperature, pH, and moisture content of soils on the rate of degradation of this herbicide have been investigated. The Taguchi experimental design method was applied to determine the relative impacts of the pertinent system variables. According to this approach, four series of experiments were performed under various operating conditions. In all four series the herbicide was degraded efficiently, however, the highest rate was observed at a temperature of 35°C, pH 6, and at 80% moisture content of the soil. A kinetic model for the biodegradation of the herbicide was developed for this particular conditions based on the Monod type growth equation and autocatalytic behavior of the decomposition reaction. A close correlation has been observed between the experimental data and those predicted from the model. The degree of agreement was between 85–95%. 相似文献
Multiple-point statistics (MPS) provides a flexible grid-based approach for simulating complex geologic patterns that contain high-order statistical information represented by a conceptual prior geologic model known as a training image (TI). While MPS is quite powerful for describing complex geologic facies connectivity, conditioning the simulation results on flow measurements that have a nonlinear and complex relation with the facies distribution is quite challenging. Here, an adaptive flow-conditioning method is proposed that uses a flow-data feedback mechanism to simulate facies models from a prior TI. The adaptive conditioning is implemented as a stochastic optimization algorithm that involves an initial exploration stage to find the promising regions of the search space, followed by a more focused search of the identified regions in the second stage. To guide the search strategy, a facies probability map that summarizes the common features of the accepted models in previous iterations is constructed to provide conditioning information about facies occurrence in each grid block. The constructed facies probability map is then incorporated as soft data into the single normal equation simulation (snesim) algorithm to generate a new candidate solution for the next iteration. As the optimization iterations progress, the initial facies probability map is gradually updated using the most recently accepted iterate. This conditioning process can be interpreted as a stochastic optimization algorithm with memory where the new models are proposed based on the history of the successful past iterations. The application of this adaptive conditioning approach is extended to the case where multiple training images are proposed as alternative geologic scenarios. The advantages and limitations of the proposed adaptive conditioning scheme are discussed and numerical experiments from fluvial channel formations are used to compare its performance with non-adaptive conditioning techniques. 相似文献
Salpingoporella species from algal bearing of Barremian-Aptian limestones in the Kopet Dagh basin (NE of Iran) are described. Different species (S. cemi, S. hasi, S. heraldica, S. hispanica, S. milovanovici, S. muehlmbergi, S. parapiriniae, S. piriniae, S. cf. biokovensis, S. steinhauseri, S. polygonalis) are investigated from different biometrical aspects such as depositional environments and biogeographical distribution as well as their systematic palaeontology from two formations (the Tirgan and Sarcheshmeh formations) in nine stratigraphic sections. 相似文献
In this article we present GeoTxt, a scalable geoparsing system for the recognition and geolocation of place names in unstructured text. GeoTxt offers six named entity recognition (NER) algorithms for place name recognition, and utilizes an enterprise search engine for the indexing, ranking, and retrieval of toponyms, enabling scalable geoparsing for streaming text. GeoTxt offers a flexible application programming interface (API), allowing for customized attribute and/or spatial ranking of retrieved toponyms. We evaluate the system on a corpus of manually geo‐annotated tweets. First, we benchmark the performance of the six NERs that GeoTxt provides access to. Second, we assess GeoTxt toponym resolution accuracy incrementally, demonstrating improvements in toponym resolution achieved (or not achieved) by adding specific heuristics and disambiguation methods. Compared to using the GeoNames web service, GeoTxt's toponym resolution demonstrates a 20% accuracy gain. Our results show that places mentioned in the same tweet do not tend to be geographically proximate. 相似文献
