Search results for "Sludge"
showing 10 items of 320 documents
Initial pH Conditions Shape the Microbial Community Structure of Sewage Sludge in Batch Fermentations for the Improvement of Volatile Fatty Acid Prod…
2022
Conversion of wastewater treatment plants into biorefineries is a sustainable alternative for obtaining valuable compounds, thus reducing pollutants and costs and protecting the environment and human health. Under specific operating conditions, microbial fermentative products of sewage sludge are volatile fatty acids (VFA) that can be precursors of polyhydroxyalkanoate thermoplastic polyesters. The role of various operating parameters in VFA production has yet to be elucidated. This study aimed to correlate the levels of VFA yields with prokaryotic microbiota structures of sewage sludge in two sets of batch fermentations with an initial pH of 8 and 10. The sewage sludge used to inoculate th…
Modelació de sedimentadors en plantes de tractament d’aigües residuals. Aplicació al procés de fermentació – elutriació de fangs primaris
2005
La depuració de les aigües residuals requereix la consumació de molts processos de transformació de forma simultània i/o consecutiva, que fan molt difícil el seu estudi. A més, la complexitat dels processos de depuració va en augment no sols per l'aparició de requisits d’abocament cada vegada més exigents, sinó també per les noves tendències cap al desenvolupament sostenible aplicades a aquest procés i centrades fonamentalment en l’estalvi energètic i la recuperació de nutrients de les aigües residuals per millorar el seu cicle de vida. Per aquest motiu, es fa necessari l'ús d'eines de simulació que tinguen en compte tots aquests processos mitjançant un model matemàtic adequat i ajuden a de…
Mobilność wybranych metali ciężkich w komunalnych osadach ściekowych
2016
The research was aimed at determining the interaction of municipal sewage sludge with the environment in the aspect of its potential for land applications in agriculture, land reclamation and land adaptation to different uses. Sequential extraction of heavy metals according to Brümmer’s method was used in the study. A detailed interpretation of the data allowed to state that the highest content of copper was found in one of the most mobile bindings (fraction I). For other heavy metals only trace amounts were found in the bindings considered as the most mobile (fraction I-III) which proved less risk posed to the environment. The highest percentage share of heavy metals in the investigated sl…
Hydrothermal liquefaction of municipal sludge in sub- and super- critical water
2020
Hydrothermal liquefaction of municipal sludge was conducted to investigate the effects of sub- and supercritical water and of the fluid dynamic regime on the quality of the products. Preliminary experimental runs were performed at two different temperatures (350°C and 400°C) changing reaction time in order to work at fixed kinetic severity of the process. An improvement of the C content in the solid residues and of the ratio H/C of the biocrude was obtained when a stirred reactor was used both in sub- and supercritical water. A hydrocarbon fraction was separated from biocrude whose maximum yield of 25% w/w was achieved in supercritical conditions. Results showed that the cumulative energy r…
Hydrothermal liquefaction of wet waste biomass: a practical assessment to achieve an integral valorization of municipal sludge
2020
Hydrothermal liquefaction of municipal sludge was conducted to perform a practical assessment to achieve an integral valorization of this wet waste biomass. Experiments were done to investigate the effects of sub- and supercritical water and of the fluid dynamic regime on the energy recovery of the process and on the quality of the products. Experimental runs were performed at two different temperatures (350°C and 400°C) changing reaction time in order to work at the same kinetic severity of the process (LogR0=8.9, calculated as in ref. [3]). An improvement of the C % in the solid residues and of the ration of H/C of the biocrude was obtained when stirred reactor was used both in sub- and s…
Anaerobic co-digestion of microalgae and primary sludge in an anaerobic membrane bioreactor for resource recovery (biogas and bionutrients) from urba…
2020
El consumo continuo de energía primaria ha motivado a la comunidad científica a buscar tecnologías que requieran un menor consumo de recursos y fuentes alternativas de energía renovable, que puedan sustituir a los combustibles fósiles. El cultivo de microalgas en combinación con tecnologías anaerobias surgió como una tecnología prometedora y sostenible en el ámbito del tratamiento de aguas residuales. La valorización de la biomasa de microalgas mediante la digestión anaerobia (AD) permite la producción de energía a partir de corrientes de residuos. Dado que la AD de microalgas presenta algunos inconvenientes que obstaculizan la eficiencia del proceso, se ha estudiado la co-digestión anaerob…
Analysis of the Mobility of Heavy Metals in Sludge for the Sewage Treatment Plant in Daleszyce
2020
Osady ściekowe są produktem ubocznym procesów oczyszczania ścieków. Wykazują jednak wysokie właściwości nawo-zowe oraz glebotwórcze, jednak nie zawsze mogą być one wykorzystane w tym celu. Dwa główne kryteria ograniczające ich przyrodnicze wykorzystanie to zawartość metali ciężkich oraz jaj pasożytów. Osady ściekowe pobrane z oczyszczalni ścieków w Daleszycach zostały poddane analizie zawartości metali ciężkich. W tym celu wykonano analizę specjacyjną, pozwalającą podzielić całkowitą zawartość metali na cztery frakcje mobilności. Mobilność określa zdolność pierwiastka, lub któregoś z jego form, do przemieszczania się w środowisku. Badania wykonano, stosując czteroetapową procedurę BCR. Wyni…
Application of selected methods of black box for modelling the settleability process in wastewater treatment plant
2017
The paper described how the results of measurement s of inflow wastewater temperature in the chamber, a degree of external and internal recirculation in the biological-mechanical wastewater treatment plan t (WWTP) in Cedzyna near Kielce, Poland, were used to make predictions of settleability of activated sludge. Three methods,namely: multivariate adaptive regression splines (MARS), random forests (RF) and modified random forests (RF+ SOM) were employed to compute activated sludge settleability. The results of analysis indicate that modified random forests demonstrate the best predictive abilities.
The use of industrial waste materials for the simultaneous removal of ammonium nitrogen and phosphate from the anaerobic digestion reject water
2020
The European Union’s circular economy strategy aims to increase the recycling and re-use of products and waste materials. According to the strategy, the use of industry waste materials and side flows is required to be more effective. In this research, a chemical precipitation method to simultaneously remove ammonium and phosphate from the reject water of anaerobic digestion plant using calcined paper mill sludge and fly ash as a precipitant, was tested. Paper mill sludge is a waste material formed in the paper-making process, and fly ash is another waste material formed in the power plant. Objective of this research was to test whether these industrial waste streams could be used as low cos…
Hydrothermal co-liquefaction of sewage sludge and formic acid
2019
The biocrude produced by non-catalytic hydrothermal liquefaction (HTL) has a too high heteroatom content to be used directly as a fuel [1-3]. Several studies found that different H2 initial pressures during HTL experiments were ineffective in improving the biocrude yield [4-6], nevertheless it was observed that higher initial pressures of H2 brought an improvement of the concentration of light compounds in the biocrude, decreasing the average molecular weight of biocrude oil. To date H2 is mainly generated from fossil sources and realization of a possible hydrogen economy from alternative sources presents many challenges. The use of a liquid hydrogen storage media could represent for the HT…