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PL
Fosfor jest mineralnym składnikiem odżywczym koniecznym zarówno dla wzrostu roślin, jak i właściwego funkcjonowania człowieka. Przewiduje się, że złoża fosforytu mogą zostać zużyte w ciągu 100 lat, a duże zasoby fosforu występują jako typowe zanieczyszczenia w zbiornikach wodnych i glebach. W 2014 r. fosfor został zamieszczony w wykazie surowców krytycznych dla Unii Europejskiej. Dlatego niezwykle ważne jest odzyskanie fosforu w kontekście gospodarki o obiegu zamkniętym iremediacji środowiska. Jednym z możliwych źródeł dużej dostępności są komunalne osady ściekowe. W pracy przedstawiono najważniejsze techniki stosowane do odzysku fosforu z odcieków, osadów ściekowych oraz popiołu z osadu ściekowego. Zestawiono również wyniki zawartości fosforu w ściekach pochodzących z Oczyszczalni Ścieków Płaszów w Krakowie. Stwierdzono, że w osadach ściekowych i w odciekach znajdują się fosforany w śladowych ilościach. Istnieje możliwość odzysku fosforu z odcieków, osadów ściekowych oraz z popiołów osadów ściekowych.
EN
The test results for the content of total P, orthophosphates, as well as BOD₅ and COD parameters in raw and biol. treated municipal and domestic sewage were obtained from annual reports for 2020-2021 provided by the sewage treatment plant. The content of orthophosphates and total P in raw sewage and sewage after the biological dephosphatation process was analyzed and the degree of P reduction was calculated in the studied time periods. The effectiveness of biological removal of P compounds was assessed based on indicators such as the ratio of BOD₅ :total P, COD:total P and COD:BOD₅.
PL
Biologiczna stabilizacja beztlenowa, zwana inaczej fermentacją beztlenową, jest jednym z najważniejszych procesów przeróbki osadów stasowanych w oczyszczalniach ścieków. Proces ten umożliwia redukcję masy osadów przeznaczonych do zagospodarowania, zmniejsza udział patogenów oraz eliminuje odory. W procesie tym powstaje biogaz, który stanowi cenne źródło energii odnawialnej. Celem stabilizacji beztlenowej jest generowanie bezpiecznego dla środowiska odpadu, który może być wykorzystany, np. do celów rolniczych lub do rekultywacji. Stabilizacji beztlenowej poddawane są głównie osady nadmierne. Niestety stosowanie nowoczesnych technologii oczyszczania ścieków oraz zagęszczanie osadów z dodatkiem polielektrolitu powodują, że znaczna część materii organicznej zawartej w tych osadach staje się niedostępna i trudno biodegradowalna w procesie fermentacji metanowej, co wpływa negatywnie na przebieg fazy hydrolitycznej limitującej szybkość stabilizacji. W związku z powyższym konieczne jest stosowanie metod mających na celu wstępną obróbkę osadów nadmiernych przed procesem stabilizacji beztlenowej, która pozwoli na przyspieszenie fazy hydrolitycznej oraz poprawi uzyskiwane w procesie efekty. Jedną z takich metod jest dezintegracja ultradźwiękowa.
EN
Anaerobic biological stabilization, known as anaerobic digestion, is one of the most important sewage sludge treatment processes used in wastewater treatments plants. This process enables reducing the mass of sludge intended for management, reduces the share of pathogens and eliminates odours. In this process, a biogas is produced, which is a valuable source of renewable energy. The purpose of anaerobic stabilization is to generate environmentally safe waste that can be used, for example, for agricultural purposes or for reclamation. Excess sludge is mainly subjected to anaerobic stabilization. Unfortunately, the use of advanced wastewater treatment technologies and sludge thickening with the addition of polyelectrolyte makes a significant part of the organic matter contained in the sludge unavailable and difficult to biodegrade in the process of methane fermentation, which negatively affects the course of the hydrolytic phase, limiting the rate of stabilization. Therefore, it is necessary to use methods aimed at the pre-treatment of excess sludge before the anaerobic stabilization, which will allow for the acceleration of the hydrolytic phase and improve the effects obtained in the process. One of such methods is ultrasonic disintegration.
PL
Procesy stosowane w oczyszczalniach ścieków nie gwarantują usuwania metali ciężkich, a jedynie sprawiają, że zanieczyszczenia te kumulują się w osadach ściekowych. Dlatego też zawartość metali w osadach ściekowych stanowi jedno z głównych kryteriów ograniczających wykorzystanie tej grupy odpadów do kondycjonowania i nawożenia gleb, jak również do rekultywacji i rewitalizacji terenów zdegradowanych w wyniku działalności człowieka. Obecność metali w osadach ściekowych wiąże się z potencjalnym zagrożeniem, zarówno w aspekcie ekologicznym, jak i zdrowotnym. Dlatego też, tak ważne jest monitorowanie zarówno ogólnej zawartości tych zanieczyszczeń w osadach ściekowych, jak również ich form chemicznych (specjacyjnych) występowania. Narzędziem ułatwiającym podjęcie decyzji o tym, czy dany osad ściekowy może być stosowany na cele przyrodnicze, w szczególności w rolnictwie, jest analiza potencjalnego ryzyka ekologicznego.
EN
The processes used in wastewater treatment plants do not guarantee the removal of heavy metals, but only make these pollutants accumulate in the sewage sludge. Therefore, the content of metals in sewage sludge is one of the main criteria limiting the use of sewage sludge for soil conditioning and fertilization, as well as for the reclamation and revitalization of areas degraded by human activity. The presence of metals in sewage sludge is associated with a potential threat, both in terms of ecology and health. Therefore, it is so important to monitor both the total content of these pollutants in sewage sludge, as well as their chemical (speciation) forms of occurrence. A tool facilitating the decision on whether a given sewage sludge can be used for natural purposes, in particular in agriculture, is the analysis of potential ecological risk.
EN
This article presents the experience in the field of using ultrasonication as a pre-treatment method of SS (sewage sludge). On the basis of a review of the literature, the effect of pretreatment of sewage sludge by US (power ultrasound) with different parameters on SS quality parameters and energy effects of the process was presented. The status of commercial applications of US as a sewage sludge pretreatment method was also presented, using the example of wastewater treatment plants in Poland. It was shown that the effective management of SS is an important technological and environmental problem in many wastewater treatment plants. Therefore, new strategies for dealing with this by-product are constantly being sought. In large wastewater treatment plants, the dominant method of stabilizing SS is AD (anaerobic digestion). However, due to the characteristics of SS, it shows low efficiency. Among the numerous strategies, US is one of the new technologies that is finding several full-scale implementations. Its application allows for solubilization of organic matter, disruption of microbial cells, as well as SS floc description and enzyme release. A number of benefits can be obtained as a result of these developments, including increased methane production, improved reaction kinetics and removal of organic matter, as well as enhanced settability and dewatering of SS, thus contributing to savings in wastewater treatment plants.
EN
The aim of the study was to evaluate the effect of coal mining waste and its mixtures with municipal sewage sludge and waste rock wool from cover crops on the formation of selected properties of degraded anthropogenic soil. Under the conditions of a pot experiment, coal mining waste and its mixtures with 2.5 and 5% sewage sludge and mixtures supplemented with 1% addition of waste rockwool from cover crops were introduced (in a ratio of 1:1) into the degraded anthropogenic soil. White mustard was grown on the substrates in the first year and maize in the second year. The pH, EC, and sorption properties were determined in soil samples taken before of the plants and after their harvest. The results showed that the addition of coal mining waste and its mixtures with municipal sewage sludge and waste rock wool improved the soil pH and sorption properties. The management of coal mining waste and waste optimising its properties for the production of fertilizing agents can be an effective strategy within a circular economy, which at the same time will increase the efficiency of the management of degraded and poor-quality soils.
EN
The valorization of sewage sludge, a by-product of wastewater treatment by anaerobic digestion (AD), is getting more attention as a result of the advantages it provides for the environment and economy. The current investigation is an experiment performed in a lab setting using a batch-operated anaerobic digestion reactor with a mesophilic temperature of 35°C. This study examined the generation of experimental biogas and biodegradability .The effect of pretreatment by methanogenic bacteria growth medium on anaerobic digestion of sewage sludge was studied on three different concentrations of growth media, a control, and a low, medium and high concentration of culture medium, with cumulative biogas production of 610N ml /gVS added, 750 N ml /gVS added, 900 N ml /gVS added, 10 N ml /gVS added, respectively, with biodegradability rate of 52.16%, 56.5%, 74.04%, 28.70% respectively. Biogas production was enhanced at a medium concentration of culture medium and inhibited at a high concentration during anaerobic digestion of sewage sludge. Additionally, a theoretical biogas estimate was evaluated using four kinetic models (Logistic function, Modified Gompertz, Transference function, and First order); which were utilized to match the experimental biogas generation process involving the anaerobic digestion of untreated and pretreated sewage sludge by various concentrations of growth media of methanogenic bacteria . The kinetic findings demonstrated that both models, Modified Gompertz and Logistic function, were useful for predicting biogas output and matched experimental biogas production.
EN
The article is devoted to a comprehensive consideration of various options for the disinfection of sewage sludge. It is noted that the processes of sludge disinfection are still insufficiently studied, it is difficult to choose the appropriate treatment method in accordance with the physicochemical properties of the treated sludge and activated sludge. A comparative analysis of sludge compositions of different wastewater treatment plants is made. The authors determined the optimal conditions for the thermal treatment of sediments - temperature regimes and processing time, providing guaranteed disinfection of the material at minimal energy costs. The possibility of disinfection of a suspension of domestic sewage sludge using the cavitation-acoustic method is considered.
EN
The aim of the study was to determine the heavy metal content of soils after sewage sludge application and to calculate the costs associated with fertilising the soil with sewage sludge, which have not been analysed in the available literature so far. The soil for the pot experiments came from villages where the soil was contaminated with heavy metals. Sewage sludge was proposed as a material for the reclamation of land degraded by the mining industry in the aforementioned settlements, and its effect on improving the physical and chemical properties of the soil after application was demonstrated. The cost of applying three doses of municipal sludge to restore areas damaged (degraded) by human activity was estimated. The calculation was carried out on the basis of KNR (National Contractors Estimator) No. 2–21 Tereny Zieleni (Green Areas) and the current prices from Sekocendbud Bulletin 5/2023 (2145), 1st quarter 2023. The cost of fertilising with stabilised sewage sludge for category II land is relatively low. The cost difference between the lowest sludge application of 50 Mg•ha-1 and the highest of 200 Mg•ha-1 is 85%. Therefore, it is cost-effective to apply the highest possible sludge dose per unit area. The study used sewage sludge that was suitable for natural purposes, including agricultural use, and that met the requirements [Journal of Laws 2015, item 257]. In Karniowice, no contamination of the soil with copper, cadmium, zinc and lead was found, although the content of these metals clearly increased after sludge application at the aforementioned sludge doses. The application of sludge, even in multiple doses, had no influence on exceeding the permissible concentration for these metals according to the Regulation of the Minister of the Environment of 2015, which allowed the area to be classified as uncontaminated after sludge application. In Lgota, soil contamination standards were exceeded for cadmium, lead and zinc after sludge application. In the case of copper after sludge application, the results were in line with the regulation.
EN
The sewage sludge recycling as an agricultural land resource has received a great deal of attention worldwide. This practice has highly increased because of ever-increasing municipal wastewater production and the awareness of its fertilizing potential as amendment resources. However, there is a concern about land spreading linked mainly to health associated risks due to the presence of diverse pollutants. Thus, sewage spreading management is a key factor the guarantees benefits and avoids risks. The present work aimed to investigate the benefits and risks of sewage sludge (SS) application on agricultural land. To this end, physicochemical main parameters and bacteriological indicators, fecal coliform (FC) and fecal streptococcus (FS), of the sewage sludge generated form WWTP of Skhirat, Morocco, were performed during the period 2018–2019. The obtained results of physicochemical parameters reveal high concentration of organic matter in SS, which reach 96.3 mg/l, and in nutrients. Indeed, total Kjeldahl nitrogen TKN reaches a maximum of 3791 mg/l, potassium K+ reaches 58.71 mg/l. In addition, the average content of FC and FS are around 5.40 CFU/ml and 5.85 CFU/ml, respectively, whereas total phosphorus reaches 508.25 mg/l. In addition, concentrations of micronutrients such as Cl-, SO42-, Ca2+, Mg2+, and Na+ were high, which is interesting and could benefit for both soils and plant. Furthermore, this sewage sludge contains high concentration of heavy metals, mainly zinc and copper which could limit reuse in land spreading. The obtained results were compared to the applied standards and directives established within the framework of the agricultural spreading.
EN
The restrictions on carbon dioxide emissions introduced by the European Union encourage experimental work on new generation materials containing smaller amounts of clinker. Currently, silica fly ash from the combustion of hard coal is widely used in cement and concrete technology in Europe and in Poland. Their wide application is mainly determined by their chemical and phase composition, especially pozzolanic activity, their high fineness, similar to cement. The aim of the research was to assess the properties of fly ash from thermal treatment of sewage sludge in terms of use in concrete technology in relation to EN 450-1, ASTM-C618-03 and ASTM C379-65T. The obtained test results confirm that the tested material has a different physicochemical composition and does not meet the requirements related to the use of ash in the production of concrete. In addition, the research showed the possibility of producing ordinary concrete, modified with fly ash from thermal treatment of sewage sludge. The average compressive strength for concrete containing 15% of ash from Cracow was set at 48.1 MPa and 49.2 MPa after 28 and 56 days of maturation, for ash from Warsaw at 42.0 MPa and 45.1 MPa, and for ash from Łódź at 36.2 MPa and 36.2 MPa. The determined concentrations of heavy metals are below the maximum values to be met when discharging waste water into the ground or water, the leaching limits required for accepting inert waste for disposal and for substances particularly harmful to the aquatic environment. On this basis, it was found that the migration of heavy metals from concretes with ash addition to the aquatic environment is insignificant and should not be a significant problem.
PL
Celem badań było porównanie skuteczności usuwania WWA ze środowiska wodnego w wyniku sorpcji na biowęglach otrzymanych z pomiotu kurzego oraz komunalnych osadów ściekowych. Proces sorpcji prowadzono dla dawek biowęgli 50 i 100 mg/l. Dla każdej dawki biowęgla czas kontaktu z WWA wynosił 90 i 120 minut. Najlepsze wyniki uzyskano dla dawki biowęgla 100 mg/l i czasu kontaktu 120 minut. Dla biowęgla z pomiotu kurzego i z osadu ściekowego stężenie benzo(a)pirenu obniżyło się odpowiednio o 87,2 i 78,7% natomiast dla czterech WWA normowanych w wodzie przeznaczonej do spożycia sumaryczne stężenie obniżyło się odpowiednio o 83,5 i 80,2%. Dla pozostałych WWA większą sorpcję zaobserwowano dla dibenzo(a,h)antracenu, stężenie tego związku obniżyło się o 83,2%. Najmniejsze zmiany wykazano dla naftalenu, którego stężenie zmniejszyło się o 68,5%. Nie wykazano istotnych statystycznie różnic pomiędzy sorpcją na biowęglu z pomiotu kurzego i osadu ściekowego.
EN
The aim of the study was to compare the effectiveness of removing PAHs from the aquatic environment as a result of adsorption on biochars obtained from chicken manure and municipal sewage sludge. The sorption process was carried out for doses of biochars of 50 and 100 mg/L. For each dose of biochar, the contact time with PAHs was 90 and 120 minutes. The best results were obtained for a biochar dose of 100 mg/L and a contact time of 120 minutes. For biochar from chicken manure and sewage sludge, the concentration of benzo(a)pyrene decreased by 87.2 and 78.7%, respectively, while for four PAHs standardized in drinking water, the total concentration decreased by 83.5 and 80.2%, respectively. For the remaining PAHs, higher sorption was observed for dibenzo(a,h)anthracene, the concentration of this compound decreased by 83.2%. The smallest changes were shown for naphthalene, the concentration of which decreased by 68.5%. There were no statistically significant differences between sorption on biochar from chicken manure and sewage sludge.
PL
W niniejszym artykule zestawiono najważniejsze parametry fermentacji metanowej, prowadzonej na dwóch oczyszczalniach ścieków należących do poznańskiej spółki wodociągowo-kanalizacyjnej Aquanet S.A. - Centralnej Oczyszczalni Ścieków w Koziegłowach oraz Lewobrzeżnej Oczyszczalni Ścieków w Poznaniu. Przeanalizowano skład i jakość produkowanego biogazu oraz przedstawiono sposoby jego wykorzystania. Opracowanie obejmuje lata 2017-2022.
EN
This article summarizes the most important parameters of methane fermentation carried out at two wastewater treatment plants belonging to the Poznan water and sewage company Aquanet S.A. - The Central Wastewater Treatment Plant in Koziegłowy and the Left Bank Wastewater Treatment Plant in Poznan. The composition and quality of the biogas produced were analyzed, and ways to use it were presented. The study covers the years 2017-2022.
EN
The purpose of the article is to demonstrate practices used to supervise the use of sewage sludge for agricultural purposes. The presented research and conclusions are a trend analysis and are not to be used to penalise entities. Sewage sludge, which comes from the illegal dumping of wastewa-ter into municipal wastewater by industrial plants, contains large amounts of heavy metals. Treatment plants transfer the sludge for agricultural use. Regulations specifically restrict the mode and condi-tions for such use of sludge. Methods: the research was carried out using a proprietary questionnaire, which is a supplement to the reporting questionnaire of the National Urban Wastewater Treatment Program implemented by the State Water Company "Wody Polskie". Results: The survey was con-ducted at 208 wastewater treatment plants in Poland. The results show that the majority of wastewater treatment plants do not properly supervise the process of introducing sewage sludge into the soil. They also lack supervision of how much heavy metals from wastewater are introduced into the soil. This means that there is a very high risk of contamination of agricultural soils. The results obtained could initiate a detailed analysis of this phenomenon in Poland. A comprehensive study of the scale of the practice and its current effects is required to determine the actual condition of soil treated with sewage sludge.
PL
Celem artykułu jest przedstawienie praktyk stosowanych w ramach nadzoru nad rolniczym wykorzystaniem osadów ściekowych. Przedstawione badania i wnioski mają charakter analizy trendów i nie powinny być wykorzystywane do karania podmiotów. Osady ściekowe, pochodzące z nielegalnego zrzutu ścieków komunalnych przez zakłady przemysłowe, zawierają duże ilości metali ciężkich. Oczyszczalnie przekazują osad do wykorzystania w rolnictwie. Przepisy wyraźnie ograniczają tryb i warunki takiego wykorzystania osadów ściekowych. Metody: badania przeprowadzono z wykorzystaniem autorskiej ankiety, będącej uzupełnieniem ankiety sprawozdawczej Krajowego Programu Oczyszczania Ścieków Komunalnych realizowanego przez Państwowe Gospodarstwo Wodne „Wody Polskie”. Wyniki: Badanie przeprowadzono w 208 oczyszczalniach ścieków w Polsce. Wyniki pokazują, że większość oczyszczalni ścieków nie prowadzi właściwego nadzoru nad procesem wprowadzania osadów ściekowych do gleby. Brakuje również nadzoru nad ilością metali ciężkich ze ścieków wprowadzanych do gleby. Oznacza to, że istnieje bardzo duże ryzyko skażenia gleb uprawnych. Uzyskane wyniki mogłyby zapoczątkować szczegółową analizę tego zjawiska w Polsce. Konieczne jest kompleksowe zbadanie skali takich praktyk i ich skutków, aby określić rzeczywisty stan gleby poddanej działaniu osadów ściekowych.
EN
The article focuses on the research conducted on sewage sludge in Ternopil City, Ukraine, with a specific emphasis on its microelement composition and implications for disposal and utilisation. Bacterial contamination in both old and new sludge storage facilities is revealed by the study. It is found that the sludge holds potential as a fertiliser due to its nutrient content and organic matter, although adjustments may be necessary for specific soil conditions. However, it is determined that the permissible limits for agricultural use are exceeded by heavy metal concentrations, indicating pollution resulting from landfills, old pipes, and intensive agriculture. According to existing regulations, the sludge is considered suitable only for composting. The importance of sludge monitoring, treatment, and management is underscored by the findings, as they are crucial for ensuring safe disposal, mitigating environmental risks, and addressing potential health hazards.
PL
Artykuł koncentruje się na badaniach przeprowadzonych na osadach ściekowych w Tarnopolu na Ukrainie, ze szczególnym naciskiem na ich skład mikroelementowy oraz implikacje dla ich usuwania i wykorzystania. Badanie ujawniło zanieczyszczenie bakteryjne zarówno w starych, jak i nowych obiektach składowania osadów ściekowych. Stwierdzono, że osad ma potencjał jako nawóz ze względu na zawartość składników odżywczych i materii organicznej, chociaż może być konieczne dostosowanie do określonych warunków glebowych. Ustalono jednak, że dopuszczalne limity dla zastosowań rolniczych są przekraczane przez stężenia metali ciężkich, co wskazuje na zanieczyszczenie wynikające ze składowisk odpadów, starych rur i intensywnego rolnictwa. Zgodnie z obowiązującymi przepisami osad jest uważany za odpowiedni tylko do kompostowania. Wyniki badań podkreślają znaczenie monitorowania, przetwarzania i zarządzania osadami ściekowymi, ponieważ mają one kluczowe znaczenie dla zapewnienia bezpiecznej utylizacji, łagodzenia zagrożeń dla środowiska i przeciwdziałania potencjalnym zagrożeniom dla zdrowia.
EN
It is necessary to understand the process of anaerobic digestion (AD) of sewage sludge and to find an adequate strategy to improve the efficiency of methane production. In this work, the production of methane and detailed properties of sludge are determined. The physico-chemical parameters of the digester 1 'D1' and the digester 2 'D2' remain in the optimal range of AD stability with a median value of pH (7.82; 7.93); Temperature (36.70; 37.10°C); alkalinity (3.52; 3.58 g/L); and volatile fatty acids (0.47; 0.52 g/L), respectively. This paper focuses on the performance optimization of the methane production by kinetic models of two continuous digesters in a wastewater treatment plant in Kenitra City, Morocco. Mathematical models used in anaerobic digestion are: Modified Gompertz, transference functions, and logistics functions. These kinetic models have benefitted experimental methane production for both digesters. Results show that all the models used are appropriate to optimize the kinetic parameters for producing methane, showing that the transference function is the most suitable model for predicting kinetic results.
EN
The storage and disposal of sewage sludge from municipal wastewater treatment plants is becoming an increasing problem on a global scale. The attention of scientists is directed to the search for unique technologies to manage them. Firing sewage sludge in furnaces and producing lightweight aggregates and granules constitutes an innovative method of its disposal. The resulting granules could be a substitute for commonly used materials such as perlite, vermiculite, expanded clay, or LSA, and could be used as a secondary material in the construction industry, including road construction, as various types of ballast, and as an equivalent to aggregate in concretes. However, given that sewage sludge is increasingly used in biogas production, it does not completely decompose in the process and is still a problematic waste for many municipal treatment plants. Therefore, the use of sewage sludge pellets in construction, or any other industry, could revolutionize the market. The purpose of the conducted research was to evaluate the heat-insulating properties of granules produced from sewage sludge from the Municipal Wastewater Treatment Plant "Łyna" in Olsztyn used as a heat-insulating material.
EN
This paper presents an evaluation of the use of drilling tailings in reclamation and development of physical and chemical properties of degraded soils. Composites with drilling wastes and other wastes, useful for the reclamation of degraded soils and their reconstruction in devastated areas, were used in the tests. Comparative objects were anthropogenic soil fertilized with NPK and manure at a dose of 30 Mg/ha + NPK. The research shows that the tested anthropogenic soil was characterized by very poor sorption properties, and especially the composites with the participation of the tested waste improved the described properties. The composite with sewage sludge from ZA Puławy had a more favorable (by approx. 20%) effect on the sorption capacity of the reclaimed anthropogenic soil than the composite with municipal sewage sludge from Lublin. The effect of the tested composites on reducing the hydrolytic acidity of the reclaimed soil was similar, but much more favorable than that of manure. The results of the conducted research confirmed that drilling wastes have environmentally valuable properties, but due to their unbalance, they should not be used alone, but in composites with properly selected other wastes, such as manure or sewage sludge.
EN
The aim of the research was to investigate the effect of ultrasound waves on the recovery of heavy metals (HMs) from sewage sludge. For this purpose, we conducted a three-step sequential extraction process proposed by the Community Bureau of Reference (BCR; presently the Standards, Measurements and Testing Programme). In the experiment use was made of certified reference material ERM-CC144 SEWAGE SLUDGE (Joint Research Centre; JRC). The content of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) in certified material was determined by atomic absorption spectrometry using the Avio 200 ICP-OES apparatus (PerkinElmer Inc.). To reduce the sequential extraction time, ultrasound treatment was used instead of long hours of shaking. Sonication was conducted in an ultrasonic bath (Sonic-5; Polsonic). The sonication time was set at 20, 40 and 70 minutes. The frequency, power and temperature during the ultrasound treatment were kept constant. The recovery values of heavy metals obtained by the modified sequential extraction method were at similar levels to those achieved by the conventional one. Moreover, it has also been shown that after only 20 minutes of sonication, the recovery values can be obtained similarly as for the conventional method. In order to check whether the ultrasound waves have a significant impact on the distribution of heavy metals in the chemical fractions of sewage sludge, the percentage share for each element was calculated and the potential ecological risk analysis was conducted. This was possible thanks to the fact that the material used for production of ERM-CC144 (JRC) is sewage sludge of domestic origin. The obtained results revealed that ultrasound treatment does not significantly influence the distribution of analysed heavy metals in the chemical fractions of sewage sludge, with one exception, i.e., Zn. The assessment of the ecological risk was performed using Risk Assessment Code (RAC) index, which includes the content of metals in the most mobile fraction, i.e., bound to carbonates. The calculated values of RAC indicated that Zn posed the highest ecological risk. However, it can be also confirmed that the application of ultrasound treatment in the sequential extraction procedure does not have a significant impact on the interpretation of results of the ecological risk assessment. What is more, it confirms the legitimacy of using the discussed modification in the sequential extraction of heavy metals from sewage sludge.
PL
Celem pracy było zbadanie wpływu oddziaływania fali ultradźwiękowych na wielkość odzysku metali ciężkich z osadów ściekowych. W tym celu przeprowadzono proces trzystopniowej ekstrakcji sekwencyjnej zaproponowanej przez Community Bureau of Reference (BCR; aktualnie Standards, Measurements and Testing Programme). W badaniach wykorzystano certyfikowany materiał odniesienia ERM-CC144 SEWAGE SLUDGE (Joint Research Centre; JRC). Zawartość metali ciężkich (Cd, Cr, Cu, Ni, Pb, Zn) oznaczono przy użyciu spektrometru absorpcji atomowej Avio 200 ICP-OES (PerkinElmer Inc.). Aby skrócić czas ekstrakcji sekwencyjnej, w miejsce wielogodzinnego wytrząsania zastosowano obróbkę ultradźwiękami. Proces nadźwiękawiania prowadzono w łaźni ultradźwiękowej (Sonic-5; Polsonic). Czas nadźwiękawiania wynosił: 20, 40 i 70 minut. Częstotliwość, moc oraz temperaturę podczas obróbki ultradźwiękowej utrzymywano na stałym poziomie. Wartości odzysków dla metali ciężkich uzyskane z zastosowaniem zmodyfikowanej metody ekstrakcji sekwencyjnej były zbliżone do tych otrzymanych dzięki metodzie konwencjonalnej. Ponadto wykazano również, że już po 20 minutach nadźwiękawiania można uzyskać wartości odzysków jak dla metody konwencjonalnej. W celu zbadania, czy fale ultradźwiękowe wpływają istotnie na zawartość metali ciężkich w poszczególnych frakcjach chemicznych osadów ściekowych, obliczono udział procentowy dla każdego z pierwiastków, a następnie przeprowadzono ocenę potencjalnego ryzyka ekologicznego. Ocena ta była możliwa dzięki temu, że w skład materiału ERM-CC144 (JRC) wchodzą osady ściekowe pochodzenia komunalnego. Uzyskane wyniki wskazują, że obróbka ultradźwiękowa nie wpływa istotnie na udział analizowanych metali ciężkich we frakcjach chemicznych osadów ściekowych, za wyjątkiem cynku. Ocenę ryzyka ekologicznego przeprowadzono przy pomocy wskaźnika Risk Assessment Code (RAC), który uwzględnia zawartość metali w najbardziej mobilnej frakcji, czyli tej związanej z węglanami. Obliczone wartości RAC wskazują, że największe ryzyko ekologiczne powoduje cynk. Można również stwierdzić, że zastosowanie ultradźwięków w procedurze ekstrakcji sekwencyjnej nie wpływa istotnie na interpretację wyników oceny ryzyka ekologicznego. Jednocześnie potwierdza to zasadność stosowania omawianej modyfikacji w procesie ekstrakcji sekwencyjnej metali ciężkich z osadów ściekowych.
EN
Concrete is currently the most widely used man-made composite material and second only to water in the entire range of materials used. It is a material with a high potential to adapt to specific operating conditions and can be made from local raw materials (aggregate, cement, water, and mineral additives), which can be selected to minimize the carbon footprint. The use of fly ash from the thermal conversion of sewage sludge in concrete is in accord with the advice on waste management proposed in the European Union. This paper presents the results of research on the effect of the partial replacement of Portland cement with this material on the strength parameters, frost resistance, and carbonation of concrete compared to reference concrete and to concrete containing a conventional additive – siliceous fly ash. In addition, the potential environmental impact of the use of sewage sludge ash was investigated by determining the leachability of heavy metals. Concrete mixtures of C20/25 ordinary concrete, based on CEM I 42.5R Portland cement, with varying ash contents comprising 0–20% of the cement mass, were produced for the experimental work. The obtained test results confirmed the possibility of producing plain concrete modified with fly ash from the thermal treatment of sewage sludge and the concrete’s compliance with the environmental requirements relating to the leaching of heavy metals.
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