Mechanochemical activation and spark plasma sintering of the lead-free Ba(Fe1/2Nb1/2)O3 ceramics

Abstract: This paper investigates the impact of the technological process (Mechanochemical Activation (MA) of the powder in combination with the Spark Plasma Sintering (SPS) method) on the final properties of lead-free Ba(Fe1/2Nb1/2)O3 (BFN) ceramic materials. The BFN powders were obtained for different MA duration times (x from 10 to 100 h). The mechanically activated BFN powders were used in the technological process of the BFN ceramics by the SPS method. The measurements of the BFNxMA ceramic samples included the following analysis: Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), DC electrical conductivity, and dielectric properties. X-ray diffractions (XRD) tests showed the appearance of the perovskite phase of BFN powders after 10 h of milling time. The longer milling time (up 20 h) causes the amount of the perovskite phase to gradually increase, and the diffraction peaks are more clearly visible. Short high energy milling times favor a large heterogeneity of the grain shape and size. Increasing the MA milling time to 40 h significantly improves the microstructure of BFN ceramics sintered in the SPS technology. The microstructure becomes fine-grained with clearly visible grain boundaries and higher grain size uniformity. Temperature measurements of the BFN ceramics show a number of interesting dielectric properties, i.e., high values of electric permittivity, relaxation properties with a diffusion phase transition, as well as negative values of dielectric properties occurring at high temperatures. The high electric permittivity values predestines the BFNxMA materials for energy storage applications e.g., high energy density batteries, while the negative values of dielectric properties can be used for shield elements against the electromagnetic radiation

Use of Vermicompost from Sugar Beet Pulp in Cultivation of Peas ( Pisum sativum L.)

A properly conducted vermicomposting process is an environmentally friendly technology used to transform selected organic waste into vermicompost. This organic fertilizer is increasingly used in agriculture and horticulture as an alternative to mineral fertilizers. Research has investigated the use of vermicompost made from the waste mass of sugar beet pulp as a soil additive in the cultivation of peas (Pisum sativum L.). Experimentally, five treatments consisted of: a heavy clay soil as control (SL); the same soil with 10, 25, and 50% substitution of vermicompost, (V10, V25, and V50, respectively); and a standard peat-based horticulture substrate (GS) for comparison. Analyzed pea characteristics and the content of macro and microelements in their biomass were most favorably influenced by 25 and 50% vermicompost addition, and the values obtained were similar to those in the GS treatment. The lowest values of analyzed traits for P. sativum were found in the SL group. Thus, appropriate addition of vermicompost in the construction of plant growing substrates can reduce the use of inorganic fertilizers and be an alternative to peat in the medium, contributing to reduced use of this valuable environmental resource

SLUDGE AS AN AGENT IMPROVING SOIL PROPERTIES

Sewage-treatment plants generate sludge which needs to be neutralized for legal, esthetical, and practical reasons. Economical and ecological concerns indicate that sludge, as long as it is possible, should be returned to the natural environment. The article presents the process of autothermal thermophilic aerobic digestion (ATAD) as a measure to produce biomass, which can be naturally utilized. The description of theoretical principles of the process in question is accompanied by presentation of an ATAD installation which has been functioning since 2009 at the municipal sewage-treatment plant in Olecko. Results of microbiological and chemical tests carried out in the years 2010–2012 have been analyzed. Examinations embraced sludge which was the final product of the aforementioned sewage-treatment plant

DROP IN CONDUCTIVITY OF SEWAGE SLUDGE IN THE PROCESS OF AUTOTHERMAL THERMOPHILIC AEROBIC DIGESTION

The article presents research on the assessment of electrolytic conductivity changes of sludge during the process of its autothermal thermophilic aerobic digestion (ATAD), which takes place in a two-stage installation system, operating in a municipal sewage-treatment plant. In the years 2012-2014 sludge was studied and the results were analyzed. Thickened sludge in the intermediate tank, which was then directed to installation reactors, was examined. Conductivity was measured in each tank. In this manner collected results made it possible to follow the changes of this index at consecutive stages of the system. The results were statistically analyzed and it was determined to what degree, as a result of an objective process, the values of processed sludge conductivity would change. The conclusions from the carried-out studies and from own experiments are also presented

CHANGES IN HYDROGEN ION EXPONENT OF SEWAGE SLUDGE IN THE PROCESS OF AUTOTHERMAL THERMOPHILIC AEROBIC DIGESTION

This paper presents a study on the evaluation of digested sewage sludge during the process of Autothermal Thermophilic Aerobic Digestion (ATAD), taking place as a three-tank process at a municipal waste water treatment plant in Luban, Poland. ATAD installation was manufactured by FUCHS Enprotec GmbH Mayen-Deutschland. Over the period from June 2006 to February 2010 sewage sludge digested by tha ATAD-Process was examined. The hydrogen ion exponent was measured in every tank. The results obtained indicated changes in the composition of the digesting sludge at successive stages of the process. Over the study period the ATAD-installation was in both a two- and a three-stage process. pH of sludge under study during the process of the thermophilic stabilisation changes and its value grows significantly, with the installation working in a two-stage arrangement from 6,63 to 7,99, and when the installation was operated as a three-stage system from 6,60 to 8,14. The results collected were subject to the statistical analysis. The paper presents conclusions drawn from the study and own experience

DYNAMICS OF WATER CONSUMPTION CHANGES IN A TOURIST RESORT

This work presents problems related to the water consumption in the city of Olecko situated in the north-east part of Poland in the Warmińsko-Mazurskie Province of the country, at the eastern border of the Mazurian Lake District along the trail connecting the land of the Large Mazurian Lakes with the Suwalsko-Augustowskie Lake District. Over 2011–2012 water extraction to the municipal water supply network was studied. The volume of water extracted every day was analyzed and the gathered volumes were analyzed statistically. The varying water extraction was also studied. The obtained results were presented in a graphic form. Basing on the descriptive stats and prepared diagrams certain general conclusions were drawn and the collected study figures and facts were summed up. This allowed to determine days of the highest and lowest water consumption. Also months of extreme water extraction and consumption were determined. The water extraction ranged from 1641 m3/24h to 2607 m3/24h, at an average value of 2077.4 m3/24h. Over the period under study the day of the largest water extraction and consumption was in July and the day of the lowest water extraction and consumption in December. During a week inhabitants used the highest water amount on Saturdays and the lowest on Sundays and other feast-days. Basing on the conducted measurements also the coefficient of water consumption per capita was determined. The fluctuation of this coefficient was identical as that for the water consumption. Within the period of study it ranged from 73.3 l/M 24h to 116.5 l/M 24h. The average value of the specific water consumption was 92.8 l/M 24h. For the sake of discussion the obtained results were compared with observations across the country

Analysis of the Quality of Stabilized Municipal Sewage Sludge

The sludge management of many wastewater treatment plants in Poland has not been properly solved as yet. The exploiters and designers have to cope often with the dilemma of choosing the method of processing and neutralizing sewage sludge. The method discussed in the article is only one of the options that fully fits in the trends of implementing good practices in the management of sewage sludge. It is a process technologically and economically effective and environmentally friendly. It contributes significantly to minimizing the amount of sewage sludge and allows the production of organic fertilizer instead of waste. The work discusses the quality of sewage sludge after autothermal thermophilic stabilization (ATAD). The results of investigations of the reaction of sludge, dry mass, dry organic matter, content of biogenic substances, calcium and magnesium compounds and heavy metals were analyzed

Utilization of Sewage Sludge after the Process of Autothermal Digestion

Sediments constitute one of the wastes that are generated in sewage treatment plants. The methods of their final management depend on the sewage sludge system management. One of the employed methods is Autothermal Thermophilic Aerobic Digestion (ATAD). The article presents the process of autothermal oxygen digestion of sewage sludge as a method enabling to obtain biomass, which can be used in the natural environment. In addition to the description of the theoretical basis of the discussed process, the quality of the formed sewage sludge is presented. The amount of sludge and the manner of its final utilisation were also analyzed. The results were presented on the basis of waste records kept in each of the analyzed sewage treatment plants. Sludge transfer cards in 2013-2018 were also analyzed in the sewage treatment plants where sludge undergoes the ATAD process

Analysis of Water Age and Flushing of the Water Supply Network of the Pressure Reduction Zone

The water of appropriate quality introduced in the water system changes its chemical properties. Depending on the chemical properties of water and pipe materials, various phenomena may occur, e.g. corrosion, and biofilm structure. The decreasing water demand in existing water systems leads to a reduction in the water flow velocity in the pipes. Accordingly, the age of the water in the system increases. It is especially visible at connections and long sections of the network. The deteriorating water quality along with the elapsing time of its stay in the pipes makes it necessary to perform appropriate measures, e.g. flushing the network. Water supply services usually perform them intuitively. The choice of flushing sites, times, or flow rates is not measured and verified. The age of the water and the efficiency of flushing can be simulated in computer programs. EPANET provides tools for such simulations. The research aimed to check the effects of flushing the network and the age of water in the pressure reduction zone. This is a case that is particularly prone to the increasing age of water. The research has shown that the network flushing sites used so far contribute to the exchange of water in the main water pipes. The simulations showed the need for the additional flush in new places, and in the tested case, the age of the water in the pipes is as much as the intervals between subsequent rinses

Optimization of Energy Consumption in the Pumping Station Supplying Two Zones of the Water Supply System

Water supply pumping stations are among the main energy-consuming elements in the water supply system. The energy optimization of a pumping station can significantly affect the energy consumption of a water utility. This article deals with the energy optimization of water pumping stations. The work assumes several variants of optimization of water supply pumping stations through changes in the water supply system, pressure changes in the pumping station, and modification of the number of pumps. After analyzing the network, conducting field tests, and creating a model of the water supply network, the network was calibrated in order to reproduce the existing water network as accurately as possible. Then, a variant analysis was performed, and the best optimization method for the pumping station was selected. In two variants, there was a decrease in electricity consumption; in three there, was an increase; in one, there was no change. By connecting the DMA zones and modifying the pressure in the pumping station, the energy consumption of the pumping stations was reduced. On this basis, it was found that it is possible to optimize the water pumping station by modifying the pumping station and work related to the network layout