Papers by Keyword: Sludge

Abstract: Investigating the intricate microbial communities within a textile wastewater treatment system is crucial for understanding their potential role in the process, and possibly for process optimization in the future. Dye-containing wastewater sludge samples were collected from a textile industry treatment plant. Employing total genomic DNA extraction, amplicon sequencing, and sequence data analysis, this research investigated the microbial community composition in three treatment tanks. Rarefaction curves confirm adequate sequencing depth, with the aeration tank displaying the highest reads. Alpha diversity reveals richer microbial communities in the anoxic tank, while all samples demonstrate similar diversity and species richness. Proteobacteria dominate at the phylum level, predominantly in the aerobic tank, signifying their involvement in nitrogen removal. Conversely, anoxic sludge features Planctomycetota and Thermotogota, potentially participating in anaerobic processes. Genus-level analysis highlights the potential significance of SM1A02 in nitrogen metabolism under anoxic conditions, while Denitratisoma dominates in aerobic tank, indicating denitrification as the main process in this tank. This study offers valuable insights into the microbial community members present in the textile wastewater treatment system, and their potential roles, towards a more sustainable biodegradation strategies of dye-containing wastewater.

Abstract: This paper presents a case study of solar drying of hydroxide sludge in the region of Marrakesh, Morocco. The experiments of solar greenhouse drying processes of the hydroxide sludge were studied in summer and winter seasons. The representative samples were in three volumes. The greenhouse sludge dryer was designed and constructed as a horticultural plant. Results showed that the dry of the three samples was reached in only 13 hours in summer and 25 hours in winter. The time of solar greenhouse drying registered was significantly lower compared to several studies. The higher values of drying rate were obtained in early hours of experiments in summer. The maximum ranges obtained were 0.25 kg water/kgDS.h for the hot season and 0.020 kg water/kgDS.h for the cold season. The important influence of the temperature had a greater effect with wind speed on drying rate. The sludge water evaporation caused a large volume reduction with a shrinkage during the processes in both seasons.

Abstract: The aim of this work was to evaluate the possibility to solidify radioactive expanded clay balls or radioactive sludge originating from the decommissioning of NPP V1 in Jaslovské Bohunice (Slovak Republic) into the geopolymer matrices. The radioactive wastes (RAW) in the proportion of 0 wt.%, 20 wt.%, 25 wt.%, and 30 wt.% were solidified using a geopolymer mixture GEOCEM (producer GEOFIX Ltd., Slovak Republic). The value of compressive strength linearly decreased with increasing addition of RAW from the value of 16.1 MPa to 12.4 MPa for radioactive expanded clay balls solidified and from the value of 16.1 MPa to 10.6 MPa in the case of radioactive sludge. Leaching test carried out according to ANSI/ANS 16.1.1986 showed that the calculated value of leachability index L_i at the highest proportion (30 wt.%) of radioactive expanded clay balls or radioactive sludge reached the value L_i = 10.3 or L_i = 9.7, respectively.

Abstract: This work presents studies on the material composition and physico-mechanical characteristics of an alumina-containing estimate formed during the production of aluminum on electrolyzers with self-baking anodes during technological operations. The material is a mixture of fine powder 2.5 mm in size (62.78% on average mass) with the presence of pieces of material ranging in size from 0.5 to 6 cm (average 20.26% by weight). The samples contain pieces of hardened aluminum with sizes from 5 to 20 mm (16.96%). The largest content in the sample has the fineness classes-0.315 + 0.16 mm in the volume of 29.85% and the largest class +2.5 mm-37.22%. B It was established that aluminum is concentrated in the fractions-0.315 + 0.16 mm (45.7%) and 0.16 + 0 mm (48.8%), silicon in the fraction-0.63 + 0.315 mm (1.91%), iron at-1.25 + 0.63 mm (0.601%) and-0.63 + 0.315 mm (0.62%). The material consists of cryolite (Na₃AlF₆), chiolite (Al₃F₁₄Na₅), quartz, feldspar, carbonaceous matter and the technogenic phase of the composition (NaF) 1.5CaF₂ AlF₃. The material is characterized as non-abrasive (working index Ai - 0.0184) and very soft in relation to impact crushing (working index CWi - 3.64), the working index of ball grinding Bond (BWi - 6.47) characterizes a very low resistance to ball grinding. The implementation of the crushing operation of an alumina-containing estimate will allow the use of dry cascade-gravity and centrifugal classification to separate impurities in the form of SiO_2, and Fe₂O₃ for the use of alumina-containing material in primary aluminum technology. On the basis of laboratory tests, it is established that alumina-containing raw materials can be separated and photometric and gravitational separation methods can be used. A mathematical model of the motion of particles of primary and prepared alumina-containing raw materials in a cascade-gravity classifier was developed. The criteria and factors characterizing the alumina-containing material, as well as influencing and determining the maximum material enrichment, are established.

Abstract: The paper is devoted to the urgent issue of processing the dust waste of metallurgical-grade silicon production, i.e. wet cleaning sludge, which contains a significant amount of valuable silica. The paper analyzes the formation of finely dispersed techno-genic materials that are generated in significant quantities (up to 120 t/d) at the Kremniy JSC. The composition and properties of the silicon production wet cleaning product have been studied. In analytical studies of the wet cleaning sludge samples, the modern certified analysis techniques have been used: laser diffraction, X-ray diffraction, and X-ray fluorescence. According to the analysis, the L:S ratio of liquid sludge is 2.1:1; after dehydration, the sludge cake has a grain size of 150 μm, with the prevailing (90 %) grain size of 59.65 μm in the test sample. The chemical composition of the sludge is 95.86 % SiO₂; therefore, the wet cleaning sludge is a valuable raw material to produce metallurgical-grade silicon. Based on the analysis of the composition and properties of the silicon production wet cleaning sludge sample, we have developed a program for its processing. Sustainable sludge processing techniques are aimed at obtaining a briquetted charge, which can be used as an additive to the main raw material.

Abstract: Zinc can be found in oxide and sulfide forms in technogenic formations. Zinc oxide extraction from technogenic formations is widely used in industry. Removing zinc sulfide from technogenic formations is difficult and is currently almost never used. In the present work, the physicochemical features of zinc extraction from sulfide are considered. Process thermodynamic features and possible ways to extract zinc sulfide are shown. Also, ways of valuable commercial products, obtaining from the roasting products, are considered.

Abstract: The paper considers the existing problems of the production of ceramic products in the territory of the Russian Federation, presents the priority directions of development of this industry. The study includes the determination of the properties of samples based on the raw material base of the Orenburg region, namely, waste generated during the development of brown coal from the Tyulgansk deposit - white and red clays and nickel slag of OJSC Yuzhuralnickel Combine of the Orenburg region. The study presents data from the study of the technological properties of the raw materials, the development of the composition of the ceramic mixture. The influence of the material composition of the clay / slag mixture on the physic mechanical characteristics of the products of the experimental compositions was determined: compressive strength, fire shrinkage, water absorption and density.

Abstract: The paper presents the results of a study of the possibility of recycling water treatment sludge in the production of wood-cement composites. Sludge is formed during the treatment of sewage, containing industrial machine oil, with a sorption material, based on thermally modified chestnut tree waste (CTW). It was found that the addition of sludge leads to an increase in the density of the samples. Thus, the samples without the addition of sludge have an average density of 860 kg/m³, samples with the addition of sludge in an amount of 10 mass% - 875 kg/m³, 20 mass% - 879 kg/m³, 30 mass% - 882 kg/m³, 42 mass % - 887 kg/m³. Studies of the change in water absorption of samples, depending on the amount of sludge added, showed that the values slightly decrease for samples containing sludge, what is explained by the presence of oil in the mixture. The compressive strength of the samples with the addition of sludge in the amount of 42 mass% was 3.1 MPa, what corresponds to the regulatory requirements for a wood cement composites.

Abstract: In this study, corrosion behavior of Incoloy 800 was studied in supercritical water containing sewage sludge and oxygen at various temperature from subcritical to supercritical environment. Surface and cross-section morphologies of the oxide films on Incoloy 800 was observed by scanning electron microscope. Corrosion will be obviously accelerated by increasing temperature. And the addition of oxygen in corrosion medium will cause the formation of various inorganic salts, forming a salt deposit layer on sample surface.

Abstract: In this work, water treatment sludge from the water treatment plant was used to synthesize zeolite material. In the synthesis, the washed sludge was mixed with sodium hydroxide and then heated at 600^ºC for 6 h. After agitation, the aged material was heated in a water bath at 80^ºC for different period of aging times. Based on XRD and SEM analyses, Faujasite zeolite was obtained. Then, the feasibility of employing the obtained zeolite as adsorbent for Brilliant Green (BG) removal was investigated. The effect of adsorbent dosage and contact time were examined. Adsorption kinetics and isotherm were also evaluated. The results showed that the obtained zeolite has potential for applying as low-cost adsorbent for the removal of BG from wastewater with higher than 97% adsorption efficiency.