Obecnie beton jest najczęściej wykorzystywanym materiałem kompozytowym spośród wytworzonych przez człowieka, a drugim po wodzie w całym kompleksie stosowanych materiałów. To ekologiczny materiał wytworzony z miejscowych surowców – kruszywa, cementu, wody, domieszki i dodatku mineralnego, charakteryzujący się najmniejszym śladem węglowym. W artykule przedstawiono wyniki badań betonów klasy C20/25 na bazie CEM I 42,5R, kruszywa otoczakowego oraz popiołu lotnego z termicznego przekształcania osadów ściekowych w ilościach 5, 10, 15 i 20% masy cementu. W toku prac eksperymentalnych wykonano pomiary wytrzymałości na ściskanie po dwóch okresach dojrzewania oraz mrozoodporność F150. Zebrane wyniki badań umożliwiły porównanie właściwości betonów wytworzonych z popiołem pochodzącym z dwóch oczyszczalni ścieków. Uzyskane wyniki badań potwierdzają możliwość wytwarzania betonu zwykłego, modyfikowanego popiołem lotnym z termicznego przekształcania osadów ściekowych. Średnią wytrzymałość na ściskanie dla betonu zawierającego 20% popiołu z Krakowa ustalono na 50,1 i 50,6 MPa po 28 i 56 dniach dojrzewania, a dla popiołu z Warszawy na 42,6 i 45,7 MPa.
Air protection technologies generate massive amounts of solid wastes, including fly ash (FA). Zeolite synthesis from FA seems to be an effective method for FA utilization. In addition, fly ash zeolites (FAZs) could be used for sulfur dioxide (SO2) adsorption. Since there is a lack of sufficient information about SO2 uptake on FAZs, we investigated this phenomenon in detail. Two commercially available zeolites, 3A and SM-27, and two FAZs, one manufactured by the authors and the other obtained from Kimura Chemical Plants, were used for SO2 adsorption tests. Our experiments confirmed that FAZs could be efficient SO2 adsorbents. Observed SO2–zero emission periods varied from 2-3 min for non-activated zeolites to 7-15 min for their thermally activated counterparts. The thermal activation of FAZs increased 2-3 times their SO2 adsorption capacity, resulting in up to 38 mg of SO2/g of zeolitic material.
Our paper deals with the balance of chlorine in coal combustion and flue gas desulfurization based on measurement results acquired at two different boilers of the CEZ thermal power plant in Melnik, Czech Republic. In bottom ash and electrostatic ash 30–35% of chlorine remains and more than 60% chlorine enters flue gas desulfurization. Almost all chlorine in flue gas entering flue gas desulfurization is removed from 90% in limestone scrubbers. Only up to 8% of chlorine content leaving the scrubbers is emitted to ambient air.
In this study, the chemical characterization of solid residues, i.e., bottom ash, fly ash, and filter cake, produced from the Izmit Hazardous and Clinical Waste Incineration Plant (IZAYDAS) was investigated. The IZAYDAS is located in the city of Kocaeli in Turkey and it has been in use since 1997. Several parameters were measured, including AOX, Cl⁻, CN⁻, SO₄²⁻ and selected heavy metals including Pb, Cd, Cr(VI), Cu, Ni, Hg, As(III), and Zn. The results showed that although the temperature and furnace residence time inside the kiln are maintained for complete combustion, cold points and pyrolytic conditions may occur locally and cause the formation of products of incomplete combustion in bottom ash. Fly ash has the highest content of soluble metals among the solid residues investigated. The concentrations in leachates are generally low in filter cake. Moreover, it has been proven that the AOX levels are higher in the bottom ash than in both the fly ash and filter cake.
The influence of curing time on the shear strength of fluidized fly ash. The paper presents results of research on the influence of compaction and air and water curing on angle of internal friction and cohesion of fluidized fly ash from “Połaniec” Power Plant. It was stated that the increase in compaction resulted in an insignificant increase of the angle of internal friction and a quite signifi cant increase of cohesion. While the type and time of curing had a great influence on the angle of internal friction and cohesion. The highest values of angle of internal friction were obtained in the air curing, and the lowest in the water curing whereas in case of cohesion there was an inverse relation. The rise of curing time resulted in largely increased cohesion and small changes of angle of internal friction.
Studies were carried out on the effect of various methods of storing municipal refuse upon the survival and passage of saprophytic microorganisms (TVC, Gram positive bacteria, Gram negative bacteria, thermotolerants, yeasts), bacteria indicative of sanitary conditions (TC, FC, E. coli, FS, enterococci, Clostridium perfringens) and opportunistic pathogens (hemolytic streptococci, staphylococci, in this Staphylococcus aureus) into leachates. Studies were made from June to October using PCV columns 105 mm in diameter and 1000 mm high, in 5 combinations: 1) permeable bottom, 2) bottom sealed with a 150 mm layer of clay, 3) bottom sealed with a 150 mm layer of fly ash, 4) permeable bottom but municipal refuse mixed with fly ash, and 5) bottom sealed with a 75 mm layer of fly ash. Bacteria counts in fresh refuse were typical of untreated municipal sewage. With the exception of thermotolerants and hemolytic streptococci, bacteria and yeast counts decreased after 143 days, although to a varying extent. Leachates from municipal refuse stored in columns in particular experimental combinations usually contained the highest numbers of microorganisms during the first 35 days. Later on their counts decreased. On the average, the lowest numbers of the microorganisms were leached from the columns sealed with a 150 mm layer of fly ash, while the highest numbers were observed in the case of columns with permeable bottom and those sealed with a 150 mm layer of clay.
Both sewage sludge and fly ash are wastes. Their granulation can decrease their adverse effect. Due to the contents of biogens in the sewage sludge the granulates will have fertilizing and soil-forming properties. The aim of this study was to find such proportion of components used for production of ash-sludge granulates that would decrease the volume of extracted contaminants to meet the requirements of regulation [36] preserving their fertilizing properties. In our study two types of fly ash were mixed in various proportions with municipal stabilized sewage sludge. The obtained granulates were subjected to one- and three-stage elution tests. In the eluates the concentration of nitrogen compounds, phosphorus, magnesium, calcium and heavy metals was determined. The mixture with the same share of sewage sludge and fly ash proved to be of high fertilizing value at the same time.
On the basis of X-ray diffraction, infrared spectroscopy, and thermogravimetry examinations, it was concluded that chemically modified lignite fly ash showed a zeolite-like structure. It was found that the zeolitized coal ash samples were effective adsorbents for n-butylamine removal.
W artykule przedstawiono wyniki badań właściwości (konsystencji, gęstości, wytrzymałości na ściskanie, zginanie oraz rozciąganie przy rozłupywaniu) betonów zwykłych oraz betonów zawierających w swoim składzie włókna stalowe i popioły lotne. Do wykonania betonu wykorzystano cementy CEM I o klasie wytrzymałości 32,5R, 42,5R, 52,5R. Dla każdego rodzaju cementu wykonano beton z włóknami stalowymi w ilości 0,7% oraz włóknami stalowymi w ilości 0,7% i popiołem lotnym w ilości 5% masy cementu. Po wykonaniu badań stwierdzono, że dodanie włókien stalowych i popiołu lotnego poprawia właściwości na zginanie i rozciąganie przy rozłupywaniu, wytrzymałość na ściskanie ulega pod ich wpływem spadkowi.