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Fluoride Removal from Groundwater by Technological Process Optimization

Abstract

Fluoride removal from aqueous solutions was studied using nanofiltration and sorption techniques which have always been best key ways to deal with water contaminated by fluoride. In this presented work, we were firstly interested on fluoridated rejected water overcoming the drawback of RO membrane process of groundwater treatment plant in Baltic region (Kretinga, Lithuania). Opoka sorbent has shown effective results of fluoride sorption with efficiency higher than 77 %. In order to understand the sorption phenomenon and to validate the results obtained, we have applied experimental data on Freundlich and Langmuir isotherms which allow us to determine isotherms parameters (KF; 1/n and KL; q max) and to confirm the experiment. Because of the unacceptable tariff of drinking water treated by RO, defluoridation with nanofiltration method is proposed in this study as a solution which can replace reverse osmosis technique. For that, tests of nanofiltration for fluoride removal were carried out at laboratory scale by using nanofiltration flat sheet membranes (NF270 and NF90).

Open access
Geostatistical Methods in Water Distribution Network Design - A Case Study

Abstract

Modeling of the loads of water supply networks and their subsequent forecasting is an element necessary for making optimum decisions in the process of planning the development and operation of the water supply networks. The results of this modeling are decisive for the selection of the diameters of the pipelines and their arrangement on the water demand area. This study presents the results of estimation of average values of loads for the selected investment variants. The aim of the article is to present the possibility of simulations and analyses of the geostatistical interpolation methods. Data input in the model regarded the fragment of the real water supply network administered by the Municipal Water and Sewerage Company in Warszawa. Results of the computer analyses for the presented investment variants were related to the operating data of the water supply network and the data on water demand for the years 2014-2017 and 2018-2025. The aim of this paper is to present the advantages of GIS for the water supply systems and to prove that using the appropriate IT system, with provision of proper data processing, may lead to decisions which are optimum in view of the established, often very complex criteria.

Open access
Hydrochemical Diversity of a Large Alluvial Aquifer in an Arid Zone (Draa River, S Morocco)

Abstract

In arid areas, with rivers functioning episodically, alluvial resources are the main source of water. Considering the intensified regulation of discharge in montane catchments, supplying the intermittent rivers, in the nearest future alluvial aquifers will gain key importance for the functioning of people in arid zones. The research aimed to investigate the diversified chemistry of alluvial waters typical of large intermittent river valleys in hot arid zones as well as to analyse processes determining the water chemistry and affecting its diversity. The detailed study, carried out in October 2015, covered the Draa river valley (1100 km total length) in the region of the Mhamid Oasis. The examined water was sampled from all wells found in the study area. Concentrations of the main cations: Ca2+, Mg2+, K+, Na+, NH4 +, and Li+, anions: Cl, SO4 2−, HCO3 , and NO3 , as well as trace elements: Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, and Zn, were identified. Results were analysed with statistical, hydrochemical, and geochemical modelling methods. Alluvial waters of the eastern and western part of the oasis differed in concentrations of numerous components, what resulted from the regulation of irrigation. Specific electrical conductivity showed a 3.5-fold increase, from 3800 to 13800 μS/cm, consistent with the direction of water flow in the oasis, from east to west. Even a greater rise was observed for ions: Cl (6x), Na+ (5.5x), Mg2+ (5.0x), Ca2+, and SO4 2− (3.5x). Such a composition indicated multiionic hydrochemical type of waters dominated by Na+ and Cl. Additionally, high Pearson correlation coefficients were recorded for Na+ and Cl (0.98) as well as Mg2+ and Cl (0.97). The saturation index suggested that the main water components originated from dissolving of minerals such as halite, anhydrite, sylvite, and gypsum. Groundwater chemistry in the Mhamid Oasis was determined mainly by geogenic processes, such as dissolving of evaporates, precipitation of carbonate minerals, and ion exchange.

Open access
Hypothetical Accident in Polish Nuclear Power Plant. Worst Case Scenario for Main Polish Cities

Abstract

Poland is under threat of potential accidents in nuclear power plants located in its close vicinity, in almost all neighboring countries. Moreover, there are plans to establish a new nuclear power plant in Polish coast. In this paper the analysis of atmospheric transport of radioactive material released during a potential accident in the future nuclear power plant is presented. In the first part of study transport of radioactivity as seen from the long time perspective is analyzed. This involves trajectory analysis as a tool for describing the statistics of air pollution transport pattern and screening the meteorological situations for episode studies. Large sets of meteorological data for selected episodes were stored as a result of this process. Estimation of risk includes both analysis of the consequences and probability analysis of an occurrence of such situation. Episodes then were comprehensively studied in the second phase of the study, using the Eulerian dispersion model for simulation of atmospheric transport of pollutants. This study has proven that the time needed for reaction in case of (hypothetical) accident is enormously short.

Open access
Influence of Liming on Kinetics of Sewage Sludge Pyrolysis

Abstract

Thermogravimetry (TG) is the fast and reliable method for characterization of thermal decomposition of any material and in particular to determine the kinetics of pyrolytic decomposition of sewage sludge. Two types of sewage sludge with and without addition of lime were investigated from kinetic point of view. For TG analysis samples of selected sewage sludge were heated under the inert atmosphere of argon with constant heating rate from 303 to 1273 K; the three heating rate β = 5, 10 and 20 K/min were chosen. The iso-conversion methods of Friedman and Ozawa-Flynn-Wall were employed for analysis of TG results. As the sewage sludge decomposition is very complex process it cannot be described by a simple stoichiometric equation, therefore the so called lumping of reactions in the selected temperature ranges were used with detailed principles arising from visual analysis of DTG curve. The deconvolution of DTG curves performed according to Fraser-Suzuki asymmetric profile allowed the identification of number of lumps and their contribution to the overall mass loss. So the decomposition of sewage sludge with lime addition could be described with five groups of reactions while the one without lime by means of six lumps. The thermal decomposition of sewage sludge was assumed to proceed according to the scheme of parallel concurrent independent reactions of n-th order. The values of the apparent activation energies at different constant values of conversion degrees were determined by the iso-conversion analysis. To estimate the kinetic parameters the non-linear regression with Levenberg-Marquart optimization procedure was used. The kinetic parameters such as activation energy, pre-exponential factor, reaction order and fraction of total mass loss associated with a given reaction were determined. The impact of sewage sludge liming revealed in essential differences of pyrolysis products and pyrolysis kinetics of limed sludge and without lime one was highlighted.

Open access
Monitoring and Protection of Forest Ecological Tourism Resources by Dynamic Monitoring System

Abstract

Forest can adjust climate and provide resources for the development of the society and tourism as well as promote the progress of human civilization, which is of great significance to the survival and development of human beings. With the industrial development and the improvement of people’s living standard, the development strength on forest resources is becoming higher than ever before. As forest resources are important resources which can maintain the ecological balance of the earth, its monitoring and protection is necessary. Hence, remote sensing technology has been developed for monitoring the changes of forest resources, which has the quickness characteristics and real-time spatial information acquisition and analysis capacities. This paper firstly introduced the geographical location, geomorphology, climate status, soil and vegetation types of Zhangjiakou City, Hebei Province and the basic theory of remote sensing monitoring such as vegetation spectral reflectance and normalized differential vegetation index (NDVI). Then, the NDVI was used to analyse the vegetation coverage and area ratio of Zhangjiakou City in 2006, 2010 and 2016. It was found that the vegetation coverage during the ten years from 2006 to 2016 showed an overall trend of growth. Conclusions: It is concluded that dynamic monitoring can effectively monitor and protect forest vegetation, which provided ideas for the follow-up forestry planning and ecological tourism development in Zhangjiakou.

Open access
Multipurpose Usage of Magnetic Proppantsduring Shale Gas Exploitation

Abstract

Magnetic material may be added to proppant, as the magnetic marker allows to determine the range and efficiency of hydraulic fracturing. However, magnetic proppant may be also used in flowback fluid treatment and monitoring of environmental pollution. As a result of shale gas hydraulic fracturing, large volume of flowback fluid is created. Flow back fluid have similar properties to fracturing fluid, but it is potentially enriched with large amount of salts and organic compounds leached from shale. Magnetic proppant may serve as a heterogeneous catalyst during organic pollutants decomposition. Additionally, in case of leakage and consequently the fracturing fluid pollution, magnetic proppant is placed into the soil environment. It can be detected using magnetometric methods. This article discusses the above-mentioned issues based on the knowledge and experience of the authors and the literature review.

Open access
Natural Flavonoids as Potential Photosensitizers for Dye-Sensitized Solar Cells

Abstract

Natural flavonoids quercetin, morin, fisetin and luteolin were studied as potential photosensitizers for dye-sensitized solar cells (DSSC). Spectroscopic methods were used to investigate the formation of dye/TiO2 nanoparticles assemblies and the development of their absorption spectra. The results show that the flavonoids adsorb well on TiO2 nanoparticles and this process causes the shift of absorption spectra from the near UV into the visible range of solar light. The mode of binding of the dye molecules on TiO2 surface is analyzed by comparison of spectral absorption properties and with the use of structural differences introduced by fisetin and luteolin for discrimination between several possibilities.

Open access
Reconstruction of Dynamics of SO2 Concentration in Troposphere Based on Results of Direct Measurements

Abstract

A method for the reconstruction of the dynamics of processes with discrete time, developed in our previous papers, has been applied for study the dynamics of concentration of sulfur dioxide in lower troposphere. For the analysis, recordings of sulfur dioxide concentration from four measurement stations located in Poland (two of them has been located in huge cities and two in rarely inhabited regions) were used. We managed to obtain the deterministic and stochastic component of this dynamics. In result, we estimate the lifetime of sulfur dioxide in troposphere and the increase of sulfur dioxide concentration influenced by anthropogenic sources.

Open access
Sorption of Hydrogen Chloridein The Fluidized Bed Reactor

Abstract

Combustion of fuels, including renewable fuels and thermal treatment of waste (CFCs, pesticides), is associated with emissions of pollutants including halogens. The reversible process of sorption/desorption of HCl, in a fluidized (bubbling) bed reactor (BFB), during co-combustion of Cl-materials, was carried out. The thermal decomposition of methylene chloride (DCM, CH2Cl2) in an inert sand bed with the addition of the hydroxyapatite sorbent (HAp, Ca5(PO4)3(OH)) was investigated. The process parameters were as follows: temperature - 930 °C, the air excess - 1.3, stream rate of CH2Cl2 - 50 cm3/h. The concentration of HCl, CCl4, CHCl3, CH2Cl2, CH3Cl, COCl2 in the exhaust gases were monitored online with FTIR spectroscopy. The main chlorine product was hydrogen chloride. Samples of unprocessed HAp, taken from the bed during the process, and solid apatite residues were analyzed by X-ray diffraction (XRD). The content of chlorapatite (Ca5(PO4)3Cl) in the analyzed samples was respectively 11, 53 and 19 %. X-ray fluorescence (XRF) analysis showed the molar ratio of Ca:P:Cl was: 1.00:0.36:0.01, 1.00:0.36:0.09, 1.00:0.37:0.04 respectively. The HAp could be used as an sorbent of the HCl(g) during combustion of materials containing chlorine.

Open access