Articoli di riviste: "Evaporation sludge"

1

Marklund, S. "Dewatering of Sludge by Natural Methods". Water Science and Technology 22, n. 3-4 (1 marzo 1990): 239–46. http://dx.doi.org/10.2166/wst.1990.0207.

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Drying fron a free water surface and from a waste activated sludge was studied In three separate experimental arrangements. Evaporation in a closed chamber with a surface area of 1.0 m2 was studied with temperatures between 20 and 60°C and air flows between 75 and 300 m3/hour. The rate of evaporation varied between 351 and 746 gram/m2 hour. The efficiency varied between 11 and 20%. To increase the efficiency the air-liquid area has to be enlarged. Evaporation from two pilot sludge drying beds was studied in an open air test lasting four months. One similar bed was tested in a controlled environment. The results showed that above a critical moisture content between 600 and 1100% evaporation from sludge equals the rate of evaporation from a free water surface. Below the critical moisture level the rate decreases rapidly. Further work should be directed towards full-scale tests with covered drying beds. Special attention should be drawn to methods to improve the drying rate during the falling rate period, to two phase drying and to the evaluation of a combined dewatering system with sludge freeze drying in winter season and sludge drying in summer season.

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Mouzaoui, M., J. C. Baudez, M. Sauceau e P. Arlabosse. "How to avoid evaporation during rheological measurements of dewatered pasty sludge at high temperature". Water Science and Technology 79, n. 8 (15 aprile 2019): 1503–10. http://dx.doi.org/10.2166/wst.2019.150.

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Abstract Controlling the residence time in paddle dryers and the drying efficiency imply the knowledge of rheological behaviour of highly concentrated and pasty sludge and its temperature dependency. However, because of perturbing effects such as evaporation, measurements are not fully representative of intrinsic sludge properties. Classical techniques usually considered in the literature for evaporation control are not efficient at high temperatures. This work gives a method to control the evaporation at high temperature that can be used with any commercial rheometer. The configuration concept is to prevent water loss by limiting the contact between the sheared sludge and the environment. This configuration allows preventing evaporation up to 80 °C at least during 2 h. Its efficiency is confirmed at different total solid (TS) contents ranging from 20 to 47 wt.%.

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Idris, A., O. B. Yen, M. H. A. Hamid e A. M. Baki. "Drying kinetics and stabilization of sewage sludge in lagoon in hot climate". Water Science and Technology 46, n. 9 (1 novembre 2002): 279–86. http://dx.doi.org/10.2166/wst.2002.0259.

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A sludge lagoon has been adopted as a simple and cost effective method for dewatering of sludge. The processes occurring in a sludge lagoon include thickening, dewatering, storage and stabilization; all happening simultaneously. The objective of this study is to determine the dewatering and drying rates at pilot-scale which occur in a lagoon having different design configurations. Two types of sludge lagoons with different initial sludge depth (0.75 m and 0.375 m) were investigated to measure the drying behavior and drying efficiency. The first design is a sludge lagoon with a clay bottom where the dewatering mechanisms are decanting supernatant and evaporation. The second design is a sludge lagoon installed with a sand and underdrains system, where the dewatering mechanisms are filtration or draining and evaporation. Sludge drying kinetic models with high fitness were plotted to describe the sludge drying behavior. Drying of sludge in a sludge lagoon with a clay bottom can best be described by an exponential function. Whereas, drying of sludge in a sludge lagoon with sand and underdrains system followed a logarithmic function. A lagoon designed with sand and underdrains system and having shallower sludge depth was the most efficient. The reduction in volatile solids was lower than 4% during the study period. The drying process proceeded with an increase in dryness and decline in pH value.

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Wang, Wan Fu, Guo Li, Xing Yue Yong, Peng Liu e Xiao Fei Zhang. "The Features of Microwave Thermal Conversion of Oil Sludge". Applied Mechanics and Materials 232 (novembre 2012): 788–91. http://dx.doi.org/10.4028/www.scientific.net/amm.232.788.

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The microwave thermal conversion process of oil sludge was studied. It was found that the microwave thermal conversion process of oil sludge consisted of 5 stages: rapid heating, microwave drying, microwave hydrocarbons evaporation, microwave pyrolysis and microwave calcining. Using the residue produced from the microwave thermal treatment of oil sludge as a microwave absorbent can significantly accelerate the conversion. However, it does not show significant effect on the features of microwave thermal conversion. Meanwhile, the addition of residue at appropriate percentages increased oil recovery rate. The non-condensable gases consist of H2 and C1~C5 hydrocarbons. The recovered oil was mainly produced at microwave evaporation and microwave pyrolysis stages, consisting of 89% light oil and 11% heavy oil.

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5

Li, Xiao Ming, Shang Jie Wang, Jun Xue Zhao, Ya Ru Cui e Su Bo Hou. "A Review on the Treatments and Minimization Techniques of Stainless Steel Pickling Sludge". Advanced Materials Research 194-196 (febbraio 2011): 2072–76. http://dx.doi.org/10.4028/www.scientific.net/amr.194-196.2072.

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Pickling sludge is the deposits that generated from the neutralization of pickling waste water with calcium hydroxide in stainless steel pickling process. The main composition of pickling sludge is CaF2, CaSO4, Me(OH)n (M:Fe,Cr,Ni). Solidification /stabilization method is believed to a most economical way to dispose these wastes at present. But the process caused serious compatibilization, it not only took up the scarce land resource, but also wasted nickel, chromium and other resources, in addition, the potential harm of Cr6+ to the environment still existed. A new thought to recycle the sludge was as following. After drying the sludge, it contained mainly calcium fluoride and metal oxides. The calcium fluoride could replace fluorspar, so the sludge could be used as a raw material for AOD process, where the metal oxides were reduced into the bulk of the metal. This would not only save fluorite, but also could reduce metal oxide of sludge. With more stringent environmental demands and increasingly output of the sludge, the most effective way to reduce the sludge from source is recycling the valuable elements from waste water directly. Solvent extraction combined with vacuum evaporation, spray evaporation and resin absorption coordination were all the effective methods. The resin adsorption process would be another promising method as ion exchange resin was continuously successfully developed. It had been found that treating the waste water with positive resin can remove the metal ions, but how to completely resolve the metal from the resin was still a problem.

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6

Marklund, S. "Dewatering of Drying Beds–Combined Biological-Chemical Sludge Behaviour". Water Science and Technology 28, n. 10 (1 novembre 1993): 65–72. http://dx.doi.org/10.2166/wst.1993.0206.

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Aerobically digested sludge from a small wastewater treatment plant was dewatered on five sand drying pilot beds and four small drainage beds. The experiment was conducted in a controlled environment with constant air humidity and temperature. A total of between 147 and 263 kg of a combined biological-chemical sludge was used on each of the sand drying beds. Initial sludge total solids (TS) content was 4.6 - 5.5%. Sludge drainage was completed within 28 days, and the thinner sludge layers were drained within 16 days. The sludge evaporation phase, prior to equilibrium with air moisture, lasted a maximum of 84 days and resulted in a final TS content of 88 - 92%. The drying time to achieve 30% TS was 35-50 days, depending on initial sludge thickness. Sludge cracking behaviour or rate did not control the drying rate at less than 30% TS.

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Dellbrügge, R., K. Bauerfeld, N. Dichtl, A. Großer e S. Paris. "‘Technology transfer-oriented research and development in the wastewater sector – validation at industrial-scale plants’ (EXPOVAL) – Subgroup 6: solar sewage sludge drying: first results from investigations with a pilot plant". Water Practice and Technology 10, n. 2 (1 giugno 2015): 371–80. http://dx.doi.org/10.2166/wpt.2015.045.

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Drying sewage sludge is a major aspect of biosolids management. Several investigations were performed in a pilot-scale solar dryer for the subsequent development of design rules for solar dryers. The pilot dryer was operated outside simultaneously with a full-scale dryer and, later, in a building. Total solids in the sludge and climate data were analyzed and logged regularly during drying. The fecal coliform and ammonium content was measured as well. Operation next to the full-scale plant was intended to enable comparison of their evaporation rates. The pilot plant was operated in a building in order to assess the influence of external heat input on the drying process. The results showed constant drying progress and that drying was feasible. Although differences in evaporation rates arising from operation, aeration and scaling existed, evaporation rates comparable to full-scale dryers were observed. Under floor heating improved evaporation rates by 25%. More than 50% of total Kjeldahl nitrogen was degraded, and this could be detected as NH3 in the discharged air. Reduction in fecal coliforms could be achieved without reaching secure disinfection, as required by USEPA standard 503 (USEPA 2007).

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Oikonomidis, I., e C. Marinos. "Solar sludge drying in Pafos wastewater treatment plant: operational experiences". Water Practice and Technology 9, n. 1 (1 marzo 2014): 62–70. http://dx.doi.org/10.2166/wpt.2014.007.

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In this study, one year of operating experience with a solar sludge drying plant in Pafos wastewater treatment plant is discussed. The plant had a total area of 3,853 m2 and consisted of four parallel lines. Two types of dewatered sludge with considerably different dry matter content were used. 5,678 tn of dewatered sludge were introduced in the plant and the dried sludge had an average dried solids content of 80.9%, which corresponded to a surface annual evaporation rate of 1.14 tn H2O m−2a−1. The results indicated that solar drying may be a particularly favorable option for sewage sludge drying at climatic conditions such as those prevailing in the East Mediterranean area.

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Vo, Khoi Diep Ngoc. "STUDY ON SLUDGE TREATMENT BY THE AEROBIC STABILIZATION PROCESS COMBINES WITH BULKING AGENT AND HEATED AIR SUPPLY". Vietnam Journal of Science and Technology 58, n. 5A (12 novembre 2020): 190. http://dx.doi.org/10.15625/2525-2518/58/5a/15314.

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The paper presents the results of the evaluation of sludge decomposition ability from a municipal wastewater treatment plant by an aerobic process on the Mishimax device (MK-50). The principle of the process was based on the microorganisms activated by the bulking agent as a bio-carrier to decompose organics composition and increase the evaporation by heating. An average sludge amount of 30 kg/day was added into MK-50, with the moisture of 80.2 – 83.6 %, with the C/N ratio of around 22 - 35. The heated air with 50 oC in temperature was supplied into a rotary bioreactor during the experiment period. After every 30 days of fermentation, the results from three experiments showed that the sludge volume decreased from 83 - 85 %, the stabilization efficiency by dry weight of sludge reached at 32 - 39 %, corresponding to the average decomposition rate is 12 g/kg.day, the evaporation efficiency was more than 95 %. Sludge after stabilization process had the colour of brown-grey, pH of about 6.5 - 7.2, the humus particles with the size of less than 1 mm accounted for over 60 %, the evaluation of product indexes according to nutrients like TOC, T-N meet the standard of 10TCN 526:2002/BNN&PTNT. The stabilized sludge was used for growth plant test and compared to a market organic fertilizer under the same conditions of cultivation and monitoring. The initial results of this study were a basis for research of sludge treatment technology approaches to waste recycling orientation in urban areas in Vietnam.

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10

Li, Huan, Yang Yang Li e Yi Ying Jin. "Analyses of Coal and Sewage Sludge Co-Combustion Using Coats-Redfern Model". Advanced Materials Research 518-523 (maggio 2012): 3271–74. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.3271.

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The co-combustibility of coal and sludge was investigated with thermogravimetric analysis. The results show that the burning process of sludge can be divided into three phases: water evaporation, volatile matter volatilization and combustion, fixed carbon combustion and burning out. The ignition temperature of sludge is only 260 degree centigrade at the beginning of volatile matter combustion. The addition of wet sludge or dried sludge will reduce the burning velocity of coal, and also decrease the ignition temperature. However the blend of coal and sludge has not an obvious stage of the volatile matter volatilization and combustion. The activation energy of the sludge is lower than that of the coal. The addition of wet sludge or dried sludge will decrease the activation energy of the blend fuel, and improve the fire behavior. On the whole, the sludge addition has little influence on the combustion of the coal when the addition ratio is lower than 10%.

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Martínez-Gallardo, M. R., M. M. Jurado, J. A. López-González, A. Toribio, F. Suárez-Estrella, J. A. Sáez, R. Moral, F. J. Andreu-Rodríguez e M. J. López. "Biorecovery of olive mill wastewater sludge from evaporation ponds". Journal of Environmental Management 319 (ottobre 2022): 115647. http://dx.doi.org/10.1016/j.jenvman.2022.115647.

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12

Obianyo, JI, e JC Agunwamba. "Modeling of Evaporation Losses in Sewage Sludge Drying Bed". Nigerian Journal of Technology 34, n. 4 (27 settembre 2015): 890. http://dx.doi.org/10.4314/njt.v34i4.31.

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13

Chen, Changzhong, e Qiang Jia. "Study on engineering process and equipment operation of total treatment project of leachate and concentrated solution". Journal of Physics: Conference Series 2206, n. 1 (1 febbraio 2022): 012023. http://dx.doi.org/10.1088/1742-6596/2206/1/012023.

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Abstract The accumulation of a large amount of leachate and concentrated liquid caused by MSW is a serious potential safety hazard and environmental hazard. A full treatment project of leachate and concentrate were performed, with treatment capacity of leachate 1100 t/d and concentrate 550 t/d. The leachate treatment process adopts “pretreatment + second-stage A/O biochemistry + ultrafiltration + chemical softening + second-stage DTRO+HPRO+RO+ ion exchange”. The main processing equipment is jet aerator, submersible mixer, centrifugal pump, ultrafiltration membrane assembly, softening membrane assembly, DT membrane column, RO system, ion exchange tank, sludge mixer, sludge dehydrator, etc. The concentrated liquid treatment process adopts “pretreatment +MVR forced circulation evaporation + triple-effect evaporation +RO+ ion exchange”. The main processing equipment is filter press, feed pump, compressor, MVR heater, circulating pump, discharge pump, original liquid pump, triple-effect evaporator, RO system, ion exchange tank, etc. The treatment results show that each indicator of external drainage meets the standard requirements of GB16889-2008 and DB37/3416.4-2018. The engineering process and equipment of the project run stably, with high recovery rate, and can properly solve the problem of concentrated liquid. So, engineering process and equipment operation of total treatment project of leachate and concentrated solution were studied, which has important reference significance for the full treatment of leachate from the national waste treatment plant.

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14

Qi, Hongyuan, Huayi Jiang, Yanzhen You, Juan Hu, Yulong Wang, Zhe Wu e Hongxin Qi. "Mechanism of Magnetic Nanoparticle Enhanced Microwave Pyrolysis for Oily Sludge". Energies 15, n. 4 (9 febbraio 2022): 1254. http://dx.doi.org/10.3390/en15041254.

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In view of the high dielectric constant of magnetic nanoparticles, this paper intends to use it as a new type of microwave absorbing medium to accelerate the microwave pyrolysis process of oily sludge. Microwave thermogravimetric reaction and pyrolysis product staged collection devices were established, respectively. The main stage of pyrolysis process of oily sludge was divided based on the thermogravimetric experiments. Mechanism was studied through the characteristics of pyrolysis products and reaction kinetics simulation. Experimental results showed that the addition of magnetic ZnFe2O4 particle did not change the microwave pyrolysis process of oily sludge and the pyrolysis efficiency could be improved. Pyrolysis process was divided into three stages, rapid heating and water evaporation stage (20~150 °C), light component evaporation stage (150~240 °C) and heavy component cracking stage (240~300 °C). Due to the addition of magnetic ZnFe2O4 particles, the content of C4~C12 increased by 3.5%, and the content of C18+ decreased by 4.1%, indicating that more recombinant components participated in the reaction pyrolysis to form light gas components. The kinetic analysis showed that the activation energy of oily sludge decreased by 36.49% and the pre-exponential factor decreased by 91.39% in stage III, indicating that magnetic nanoparticles had good catalytic activity.

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Zhai, Tian Yang, e Lin Fang. "Comparative Study on the Drying Process and Fractal Dimension of Sewage Sledge: Microwave and Air-Blast". Applied Mechanics and Materials 423-426 (settembre 2013): 1409–12. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.1409.

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A fractal model simulate the internal structure of the sludge, and on the model deduce that fractal dimension is D and the corresponding pore is r, the porosity is P. Determine the rate in the air-blast and microwave drying and calculate its different fractal dimension under different ages. The results showed that: the fractal dimension and its rate of water loss has a good correlation. Fractal dimension can describe a certain amount of sludge pore channels and internal cell rupture can cause that which would accelerate the evaporation of bound water. Microwave and the excessive energy of air-blast can be caused by temperature changes in the structure of the sludge that could change the structure of sludge.

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M, Takahashi. "The Chemical Change of the Ash Components through Phosphorus Recovery of Dehydrated Sludge by Incineration using Alkali Metal Compounds". Open Access Journal of Waste Management & Xenobiotics 4, n. 4 (2020): 1–6. http://dx.doi.org/10.23880/oajwx-16000168.

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In order to recover phosphorus from the wastewater sludge, the dehydrated sludge was mixed with the reagent of NaOH, KOH or Na 2 CO 3 , and incinerated at 750 °C or 900 °C. Phosphorus in the incinerated ash of the sludge was dissolved by the addition of the hot water, and recovered by the evaporation of the extract. The recovered phosphorus was confirmed to be an alkali metal phosphate, and the recovery rate reached about 75% regardless in these reagents (NaOH, KOH or Na 2 CO 3 ). The chemical change of the ash components were also found through phosphorus recovery.

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Shauchuk, V. V., Z. A. Hotto, A. S. Stromsky e A. A. Stromsky. "One-step method for obtaining potassium sulfate and processing of lye". Proceedings of the National Academy of Sciences of Belarus, Chemical Series 57, n. 2 (3 giugno 2021): 226–35. http://dx.doi.org/10.29235/1561-8331-2021-57-2-226-235.

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Method of obtaining potassium sulfate with basic substance content higher 92 % shown. Process conditions: 110 % KCl (10 % excess substance from stoichiometry), mixing at temperature higher 95 °C during 30 min, mixing at temperature 0 °C for 1 hour, stirrer speed 500 rpm, sludge washing 15 % water from wet sludge weight, drying the washed sludge at 70–80 °C during 1 hour. The degree of evaporation of the solution at which the double salt of potassium and ammonium sulfate precipitated was determined. The degree is 30 % at the evaporated suspension cooled, and is 45 % at hot filtration.

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Zhang, Wei, Xiaowei Wang, Qianshi Song, Qianyi Chen, Haowen Li, Zixin Yang e Xiaohan Wang. "Insight into the Effects of Inorganic Element Catalysis and Basic Fuel Properties on the Self-Sustained Smoldering Process of Sewage Sludge". Catalysts 12, n. 10 (5 ottobre 2022): 1173. http://dx.doi.org/10.3390/catal12101173.

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The objective of this study is to investigate the effects of inorganic element catalysis and basic fuel properties of sewage sludge on pyrolysis kinetics and self-sustained smoldering characteristics. The sludge pyrolysis process was explored by thermogravimetric and iso-conversion methods, and it was found that the pyrolysis process can be divided into two stages, which are mainly determined by the organic and inorganic components of the fuel. The inorganic components (e.g., Na, Fe and Mn) have a significant catalytic effect on the release of volatiles and the decomposition of macromolecules. The smoldering experiment revealed that the smoldering front and the evaporation front propagated at stable but different speeds. Among the five fuels, SS4 has the highest smoldering temperature (1070 °C) and the lowest propagation velocity (0.7 cm/min of smoldering velocity and 0.3 cm/min of evaporation velocity), while the carbon density mainly determines the heat release in the oxidation process, and the inorganic elements play a significant catalytic role at different temperatures. The obtained thermodynamic and smoldering characteristics facilitate the development and optimization of the disposal of sewage sludge, emphasizing the importance of considering feedstock composition.

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19

Grüter, H., M. Matter, K. H. Oehlmann e M. D. Hicks. "Drying of Sewage Sludge – An Important Step in Waste Disposal". Water Science and Technology 22, n. 12 (1 dicembre 1990): 57–63. http://dx.doi.org/10.2166/wst.1990.0100.

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Industrial drying techniques are successfully used processes. They are usually used for the production of base materials for industries such as food, chemical and pharmaceutical. These processes can be transferred without any difficulty for the drying of sewage sludge. Thermal drying as a process for the purpose of water removal is an important link in waste management between sludge production and sludge disposal. Two systems, convection and contact drying, are here compared. Contact drying in the thin film evaporation process is explained. Explanation and proposed uses of the single and two-stage drying systems will be discussed. Finally a short review of incurred expenses will be given.

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Surikova, Alisa, Elena Sytsyanko, Ekaterina Solov’eva e Liliya Mukhametova. "Increasing the productivity of a plant for moisture evaporation from oil sludge by application of efficient method for technological parameters calculation". E3S Web of Conferences 178 (2020): 01071. http://dx.doi.org/10.1051/e3sconf/202017801071.

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The paper presents the method of heat calculation of recovery stages for the plant of moisture evaporation from oil sludge. It enables to increase the plant power and reduce fuel consumption per one unit of evaporated moisture in heating boiler.

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Wang, Kai Feng, Na Peng e De Liang Liu. "Physicochemical Properties of Artificial Soil Composed of Sewage Sludge, Fly Ash, and Slag". Applied Mechanics and Materials 178-181 (maggio 2012): 880–84. http://dx.doi.org/10.4028/www.scientific.net/amm.178-181.880.

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The pH, electric conductivity (EC), nutrients, heavy metals, water-holding capacity and water permeability of stabilized sewage sludge were investigated by mixing municipal sewage sludge with alkaline fly ash and slag. The results indicate that the evaporation of soil moisture increases and water-holding capacity decreases in these artificial soils with an increase of slag, and the infiltration rate of artificial soils increases to improve its water permeability by adding slag to sewage sludge. The pHs of stabilized artificial soils range from 7.5 to 8.0 for a weak alkaline soil, which tend to be neutral by adding slag to sewage sludge. The ECs of stabilized artificial soils range from 2.93 to 3.71 mS•cm-1, indicating the higher salt content in these artificial soils. The nutrient contents of stabilized sewage sludge are up to a high fertilizer level and available nutrients increase with the increase of the ratio of slag to sewage sludge in these artificial soils. Cd, Ni, Pb, Cu and Zn for all artificial soil treatments are lower than control standards for pollutants in sludge and fly ash for Agricultural use.

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Li, Kai, Ao Cai, Yijun Tang e Xianyong Zhang. "Heat and Mass Transfer Characteristics of Oily Sludge Thermal Desorption". Processes 12, n. 1 (21 gennaio 2024): 227. http://dx.doi.org/10.3390/pr12010227.

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Oily sludge is a loose material containing solid and multiple liquid components. Thermal desorption is an efficient method of disposing of liquids from oily sludge. Most existing studies have mainly discussed the effect of some external process parameters on thermal desorption, with little discussion on the heat transfer characteristics and the variation in the wet component mass of oily sludge under heating. Small-scale experiments have been performed to measure the rise in temperature and liquid phase content change of the sludge during heating. The temperature rise rate increases with material density and increases faster during the initial heating stage, while it slows down as the liquid phase evaporates. The adhesive shear stress is determined by measuring the pulling force of the test rod, which decreases with decreasing water content and increases significantly with decreasing oil phase content. Heat transfer and energy distribution models have been developed to calculate the rise in the temperature of materials and the evaporation of contained liquids. The heat and mass transfer processes are obtained from simulation calculations by taking the initial material with a mass content of 25% water and 10% oil under a heating temperature of 500 °C. When the heating time reaches 135 min, the drying region reaches the boundary of the test container, at which the material temperature exceeds 350 °C. During the evaporation of different liquid-phase components, there are multiple segments in the corresponding temperature curves. The processing time and heat source temperature can be reasonably determined by analyzing the temperature rise of the material, and the effect of the disposal of liquids from oily sludge can be predicted by analyzing the changes in liquid content. The results may guide the formulation of process parameters for engineering project schemes for oily sludge disposal.

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Pervov, Alexei, Htet Zaw Aung e Dmitry Spitsov. "Treatment of Mine Water with Reverse Osmosis and Concentrate Processing to Recover Copper and Deposit Calcium Carbonate". Membranes 13, n. 2 (25 gennaio 2023): 153. http://dx.doi.org/10.3390/membranes13020153.

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Mine water usually contains heavy metals and other inorganic and organic pollutants that contaminate water bodies. Reverse osmosis (RO) techniques are capable of producing purified water that meets discharge regulations. However, the problem of RO concentrate disposal and utilization is still not solved. The well-known zero liquid discharge (ZLD) process provides total concentrate utilization at the power industries but seems unreasonably expensive for the treatment of large amounts of mine water due to required chemical softening and the evaporation of concentrate. In the present article, a new approach to increase the recovery of reverse osmosis and to avoid high operational costs is demonstrated and discussed. The new technique involves radical RO concentrate flow reduction and withdrawal, together with dewatered sludge. The idea to “hide” concentrate in dewatered sludge is proposed and demonstrated during experiments. The article demonstrates results of the conducted experimental program aimed at reduction of volumes of all liquid wastes produced during mine water treatment using a new approach to concentrate it with a cascade of nanofiltration membranes and to reach a TDS value of 110-120 grams per liter. The obtained concentrate is mixed with the wet sludge, which is further dewatered and withdrawn together with the dewatered sludge. Experiments are conducted that demonstrate a reduction in calcium in the concentrate due to deposition of calcium carbonate on the “seed crystals” in the circulation mode. Another distinguishing feature of the new technique is the separation of concentrate into two streams containing high concentrations of monovalent ions (sodium and ammonium chlorides) and divalent ions (calcium, magnesium and copper sulphates). Flow diagrams of the processes are presented to demonstrate the water treatment technique used to produce deionized water and two types of sludges: sludge after clarification and sludge after calcium carbonate deposition.

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Park, Ki-Tae, Byung-Ran Lim e Soo-Koo Lee. "Drying characteristics of sewage sludge using vacuum evaporation and frying". Journal of Material Cycles and Waste Management 12, n. 3 (settembre 2010): 235–39. http://dx.doi.org/10.1007/s10163-010-0293-x.

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Ishii, H., K. Tanaka, M. Aoki, T. Murakami e M. Yamada. "Sewage Sludge Composting Process by Static Pile Method". Water Science and Technology 23, n. 10-12 (1 maggio 1991): 1979–89. http://dx.doi.org/10.2166/wst.1991.0654.

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This paper reports the results of experiments on the static pile composting process undertaken in different conditions. The experiments have revealed the following:–In order to compost dewatered sludge with polymer without any bulking agents, we used recycled compost to adjust the moisture content of dewatered sludge.When the moisture content of feed mixture, which was dewatered sludges and recycled composts, was lowered to approximately 50%, the raw sludge could be composted by either natural ventilation or intermittent aeration.–When the BOD of feed mixture was lower than 50 g/kg-DS, the fermentation temperature did not reach 60°C and the moisture content of the mixture was not lowered during composting period.–The required composting time was approximately 50 days for natural ventilation (at an average temperature of 10°C or 24°C) and approximately 35 days for intermittent aeration (at an average temperature of 10°C to 24°C), when the moisture content and the BOD of finished compost was 40% or less and 30 g/kg-DS or less, respectively.–There was a highly positive correlation between the amount of water evaporated and the amount of BOD removed. This result suggested that the amount of water evaporation could be deduced from the amount of BOD removed.

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Moiambo, Osvaldo, Raúl Mutevuie, Filipa Ferreira e José Matos. "Modelling Faecal Sludge Dewatering Processes in Drying Beds Based on the Results from Tete, Mozambique". Sustainability 13, n. 16 (11 agosto 2021): 8981. http://dx.doi.org/10.3390/su13168981.

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Abstract (sommario):

Currently, in sub-Saharan African countries, 65 to 100% of the urban population is served by on-site sanitation systems, typically pit latrines and septic tanks. Faecal sludge dewatering in drying beds is one of the most commonly adopted low-cost treatment technologies in developing countries due to favourable climate conditions in terms of temperature and radiation and because their operation and maintenance are simple. Nevertheless, research in tropical dry zones regarding these processes is scarce. In this paper, a mathematical model for faecal sludge dewatering in sludge drying beds (SDBs) focusing on gravity drainage and evaporation processes is presented and discussed. Experimental campaigns were carried out at a pilot site in Tete, Mozambique, to determine the model parameters. The results suggest that the model can be used to estimate, in similar situations, the dewatering process of different types of faecal sludge. The present research might be considered as a contribution to the design and operation of SDBs, supporting sludge management and allowing the estimation of drying times and optimal loading cycles, namely, the sludge thickness and final moisture content.

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Liu, Yucheng, Maoren Wang, Mingyan Chen, Meng Zhu e Maoqi Liao. "Facilitating the natural semi-drying of oily sludge by changing the form of water". PLOS ONE 16, n. 1 (14 gennaio 2021): e0245430. http://dx.doi.org/10.1371/journal.pone.0245430.

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Abstract (sommario):

Reducing the water content of oily sludge is essential for the disposal of it. Despite conditioning and solid-liquid separation, the water content of oily sludge generally exceeds 65%. A large amount of this water exists in the form of emulsified and bound water, reducing the efficiency of water removal during the natural semi-drying process of oily sludge. To shorten the time required for natural semi-drying, this study applied an orthogonal test to screen an oily sludge modified material (OSM). The effect and mechanism of OSM on the natural semi-drying of oily sludge were studied using a thermal gravimetric analyzer (TGA), scanning electron microscope (SEM), surface tension measurement, and microscopic observations. The results show that when the ambient temperature exceeded 10°C, the OSM increased in mass by 8–10%, and the time required for the natural semi-drying of oily sludge was shortened from 15 days to less than 5 days. OSM can rupture the emulsion, reduce the surface tension, convert the emulsion and bound water in the oily sludge into free water, and accelerate the rate of water migration, diffusion, and natural evaporation from the inside of the oily sludge to the surface and air. The research results show that changing the form of water can speed up the drying of oily sludge, creating positive economic benefits in the process of oily sludge reduction and recycling.

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28

Ingallinella, A. M., G. Sanguinetti, R. G. Fernández, M. Strauss e A. Montangero. "Cotreatment of sewage and septage in waste stabilization ponds". Water Science and Technology 45, n. 1 (1 gennaio 2002): 9–15. http://dx.doi.org/10.2166/wst.2002.0002.

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Abstract (sommario):

A one year study was carried out in a waste stabilization ponds system where septage and sewage are cotreated. The system consists of two septage ponds which operate alternately followed by two ponds in series which receive the combined effluent. The septage ponds also act as evaporation ponds for the accumulated sludge. The monitoring program was divided in two phases. The results of the first phase indicate that the effluent of septage ponds has an adequate quality to be discharged into the waste stabilization ponds designed to treat sewage and that is possible to use the septage ponds to dry the accumulated sludge. Further investigation is needed to find suitable post-treatment of the sludge in order to use it in agriculture.

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29

Radovenchyk, Yaroslav, Tamara Krysenko e Maksym Poberezhnyi. "Evaporation of liquids at low temperatures". Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving, n. 4 (24 dicembre 2021): 74–81. http://dx.doi.org/10.20535/2617-9741.4.2021.248947.

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Abstract (sommario):

Ukrainian enterprises annually generate millions cubic meters of mineralized water, which is discharged into surface reservoirs, and millions cubic meters of highly concentrated solutions and suspensions, which are accumulated and stored in special sludge storages. This waste water causes irreparable damage to the environment. A new method for the evaporation of industrial concentrates by fibrous materials with capillary properties was proposed not so long ago. The use of such materials allows an effective, autonomous, cheap, and extremely simple system to be created for the evaporation for various liquids and concentrates. The research methodology was as follows. Two graduated cylinders of the same diameter were used in our research. One cylinder was filled with the liquid phase to a certain level and used to control evaporation from the surface of the aqueous medium. In the other, experimental cylinder, a vertical cotton strip was additionally placed (from 1 to 21 layers of fabric). The width of the strip was 5 cm. The length of the strip was 50 cm. The density of cotton was 100 g/m2. The research method was to determine the height of liquid phase capillary rise along the strip of fabric and to evaluate reduction in the volume of liquid that evaporates in both cylinders at set temperatures. It was found that in the absence of wind and the distance between the vertically placed strips of 7–15 mm were sufficient to ensure the maximum evaporation intensity. Our long-term experiments in natural conditions confirmed the high efficiency of the proposed method. At an average daily air temperature of 2.3 °C, there was a significant evaporation from the surface of the fabric during the day. In this case, evaporation from the water surface was not observed. It should be noted that the intensity of evaporation under natural conditions depends on a significant number of factors (temperature, wind speed, luminosity, humidity, etc.), so it is difficult to detect a direct relationship between some of them. With increase only in the liquid phase temperature, the evaporation efficiency decreased. At a temperature of 20 °C, the laboratory installation (15 layers of cotton strip) increased the evaporation intensity by more than 2 times, at 46 °C by more than 5 times, at 57 °C by almost 3 times, but at 75 °C only by about 67 %. It is obvious that heating of the liquid phase alone less influences the evaporation process from the surface of the fabric strip, which was cooled rapidly in the atmosphere at a much lower temperature. Therefore, to increase the evaporation intensity, it is necessary to increase temperature for all components of the liquid–fabric system. A fabric with suitable properties, stretched between two metal racks and immersed into the liquid phase with the lower end, can be used as a simple evaporator. Our research has shown that the use of materials with capillary properties in the treatment of liquid solutions allows simple, cheap, and efficient devices to be created for evaporating water and converting liquid waste into a solid phase.

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30

Becker, W., M. A. Schoen e B. Wett. "Solar-thermic sewage sludge treatment in extreme alpine environments". Water Science and Technology 56, n. 11 (1 dicembre 2007): 1–9. http://dx.doi.org/10.2166/wst.2007.726.

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Abstract (sommario):

In the framework of a program for environmental protection conducted by the German mountaineers' club (DAV) problems emerging from residual solids accumulating in on-site wastewater treatment plants of mountain refuges were investigated. To handle these problems in an ecologically and economically reasonable way two devices for solar-supported treatment of sludge and bio-solids have been developed. These units support gravity-filtration and evaporation of liquid sludge as well as thermal acceleration of composting processes. Two solar sludge dryers were installed and operated without external energy supply at alpine refuges treating primary and secondary sludge, respectively. Batch-filling during the season could increase load capacity and a total solids concentration of up to 40% could be achieved before discharge at the beginning of the next season. The promising results from the solar sludge dryer encouraged for the development of a solar composter. The period of temperature levels suitable for composting biosolids in mountain areas can be extended considerably by application of this technology – measured temperature distribution indicated no freezing at all.

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31

Fantasse, Azeddine, Lakhal El Khadir, Bougayr El Houssayne e Ali Idlimam. "Solar Greenhouse Drying Kinetics Efficiency of Hydroxide Sludge in Marrakesh, Morocco". Advanced Engineering Forum 51 (12 gennaio 2024): 27–36. http://dx.doi.org/10.4028/p-bmu3yr.

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Abstract (sommario):

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.

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32

Al‐Wabel, M. I., A. A. Shalaby e A. M. Al‐Omran. "Intermittent evaporation from calcareous sandy soils as affected by sewage sludge". Arid Soil Research and Rehabilitation 11, n. 1 (gennaio 1997): 85–93. http://dx.doi.org/10.1080/15324989709381461.

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33

Kim, Seok-Hwan, Byung-Ran Lim e Soo-Koo Lee. "Drying characteristics of thickened sewage sludge in oil vacuum evaporation system". Journal of Material Cycles and Waste Management 20, n. 2 (16 ottobre 2017): 1085–89. http://dx.doi.org/10.1007/s10163-017-0671-8.

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34

Đuriš, Mihal, Zorana Arsenijević, Dragan Povrenović e Tatjana Kaluđerović-Radoičić. "Drying of Waste Water Treatment Sludge in Fluidized Bed of Inert Particles". Procesna tehnika 31, n. 2 (30 dicembre 2019): 14. http://dx.doi.org/10.24094/ptc.019.31.2.14.

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Abstract (sommario):

The benefits of drying waste water treatment sludge can be seen in two main aspects: the dried sludge can be stored and further as an organic fertilizer, or it can be a source of useful (active) microorganisms that can be reused in waste water treatment. Drying of suspensions and pastes in fluidized beds of inert material is a very attractive alternative to conventional drying technologies for suspensions, due to considerably greater specific capacity expressed as capacity per unit volume, less energy consumption and less drying air consumption. High drying efficiency results from large contact surfaces and large temperature differences between inlet and outlet air. Intensive mixing of inert particles during aggregative fluidization provides approximately uniform temperature over the entire volume of the bed and there is no risk of local overheating. A number of experiments of water treatment sludge were carried out at the pilot plant with a nominal evaporation capacity up to 20 kgH2O/h. The central part of the system is a cylindrical column of 215 mm in diameter and 1200 mm height with a fluidized bed of glass spheres. Influence of the operational conditions on performance of the drying system and on the quality of dried product were examined, in order to determine optimal drying temperature in which the microorganisms present in the dried sludge remain active. The analysis of efficiency of drying, from the aspect of water evaporation capacity and air consumption was performed in order to understand the performance of the drying system. Simple mass and heat balances adequately predict the operating regime of drying system in fluidized bed of inert material.

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35

Ghrairi, Armia, Lassaad Ajam e Oualid Limam. "Mixture Design Identification of Admissible Tannery Sludge Incorporation in Fired Bricks". International Journal of Engineering Research in Africa 68 (10 aprile 2024): 11–30. http://dx.doi.org/10.4028/p-escdu9.

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Abstract (sommario):

Pollution problems caused by industrial production of leather tanneries are an important environmental issue. In the present paper we propose to study effects of tannery sludge (TS) addition in manufactured clay bricks applying a mixture design formed by different proportions of four components: Clay, two types of sand and TS. The analysis leads to an optimal practical mixture of around 10% of TS, 20% of sand and 70% of clay and this to remain with an acceptable aspect, an admissible water absorption below 15%, an admissible total shrinkage (drying and after fire) lower than 8%, a tensile strength higher than 5MPa and a thermal conductivity of 0.93 Wm-1K-1, 15% lower than the reference mixture with 0% of TS. Experimental results indicate that a temperature cycle firing up to 950°C can lead to higher tensile strength and lower water absorption compared to a cycle that reaches only 850°C. Furthermore, incorporating (TS) in the fired brick manufacturing process can lead to significant energy saving. Additionally, it was observed that a moderate inclusion of TS can enhance evaporation process. Keywords : Mixture design, Tannery Sludge (TS); Clay bricks ; Evaporation ; Strength; Water absorption; Shrinkage; Leaching; Energy.

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36

Wallin, M., A. Voll Bugten, G. Tranell e K. E. Ekstroem. "Valorization of SiMn Sludge for Production of Low-Phosphorus Ferroalloys". Journal of Sustainable Metallurgy 7, n. 3 (22 giugno 2021): 978–84. http://dx.doi.org/10.1007/s40831-021-00385-9.

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Abstract (sommario):

AbstractThe sludge generated by wet scrubbing the off-gas from a silicomanganese plant in Norway represents a significant loss in silicon and manganese values. This work seeks to extract these values in the production of ferroalloys and slags that can be utilized by alternative industries. Carbothermic smelting the sludge together with iron or iron scraps at 1600 °C produced FeSiMn alloys consisting of 57–64 wt.% Mn, 16–22 wt.% Si and 18–25 wt.% Fe. The low level of phosphorus in the sludge allowed for beneficial phosphorus concentrations as low as 500 ppmw in the metal alloys. The addition of lime to the material mix resulted in increased evaporation of alkalis, capture of sulfur in the slags as calcium sulfides and slag compositions similar to conventional steel-making slags that can be recycled accordingly. Graphical Abstract

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37

Эльмурзаев, А. А., Ю. Х. Тарамов e П. С. Цамаева. "FACILITATING THE NATURAL SEMI-DRYING OF OILY SIUDGE BY CHANGING THE FORM OF WATER". Вестник ГГНТУ. Технические науки, n. 2(28) (26 agosto 2022): 72–80. http://dx.doi.org/10.34708/gstou.2022.11.29.006.

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Abstract (sommario):

Уменьшение содержания воды в нефтесодержащем шламе имеет важное значение для его утилизации. Несмотря на кондиционирование и разделение твердой и жидкой фаз, содержание воды в нефтесодержащем шламе обычно превышает 65%. Большое количество этой воды существует в виде эмульгированной и связанной воды, что снижает эффективность удаления воды в процессе естественной полусушки нефтешлама. Чтобы сократить время, необходимое для естественной полусушки, в этом исследовании применялся метод содействия естественному полувысыханию нефтесодержащего шлама за счет изменения формы воды с применением модифицированного масляного шлама (ММШ). Влияние и механизм содействия на естественное полувысыхание нефтешлама изучали с помощью термогравиметрического анализатора (ТГА), сканирующего электронного микроскопа (СЭМ), измерения поверхностного натяжения и микроскопических наблюдений. Результаты показывают, что при температуре окружающей среды выше 10°С масса модифицированного масляного шлама увеличивалась на 8-10%, а время, необходимое для естественной полусушки нефтешлама, сократилось с 15 дней до менее чем 5 дней. Модифицированный масляной шлам может разрушать эмульсию, снижать поверхностное натяжение, преобразовывать эмульсию и связанную воду в нефтесодержащем шламе в свободную воду, а также ускорять скорость миграции, диффузии и естественного испарения воды изнутри маслянистого ила на поверхность и в воздух. Результаты исследований показывают, что изменение формы воды может ускорить высыхание нефтешлама, создавая положительные экономические выгоды в процессе уменьшения и переработки нефтешлама. Результаты исследований показывают, что изменение формы воды может ускорить высыхание нефтешлама, создавая положительные экономические выгоды в процессе уменьшения и переработки нефтешлама. Reducing the water content of oily sludge is essential for its disposal. Despite conditioning and solid- liquid separation, the water content of oily sludge is typically greater than 65%. A large amount of this water exists in the form of emulsified and bound water, which reduces the efficiency of water removal during the natural semi-drying of oil sludge. In order to reduce the time required for natural semi-drying, this study used a method to promote the natural semi-drying of oily sludge by changing the shape of water using a modified oil sludge.The influence and mechanism of assistance on the natural semi-drying of oil sludge was studied using a thermogravimetric analyzer (TGA), a scanning electron microscope (SEM), surface tension measurements and microscopic observations. The results show that at an ambient temperature above 10°C, the mass of the modified oil sludge increased by 8-10%, and the time required for the natural semi- drying of the oil sludge decreased from 15 days to less than 5 days. The modified oil sludge can break the emulsion, reduce the surface tension, convert the emulsion and bound water in oily sludge to free water, and accelerate the rate of migration, diffusion and natural evaporation of water from inside the oily sludge to the surface and into the air. The modified oil sludge can break the emulsion, reduce the surface tension, convert the emulsion and bound water in oily sludge to free water, and accelerate the rate of migration, diffusion and natural evaporation of water from inside the oily sludge to the surface and into the air. Research results show that changing the shape of water can accelerate the drying of oil sludge, creating positive economic benefits in the reduction and processing of oil sludge. Research results show that changing the shape of water can accelerate the drying of oil sludge, creating positive economic benefits in the reduction and processing of oil sludge.

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38

Синицын, Н. Н., Н. В. Запатрина, И. А. Сарычева, Ю. В. Грибкова, Е. В. Голицына e Ю. В. Донцова. "MATHEMATICAL SIMULATION OF HIGH-TEMPERATURE DRYING OF A DROP OF SCALE- AND OIL-CONTAINING SLUDGE WHEN MOVING IN A SWIRLING GAS FLOW". Proceedings in Cybernetics 22, n. 3 (2023): 66–75. http://dx.doi.org/10.35266/1999-7604-2023-3-66-75.

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Abstract (sommario):

The article presents an examination of the movement trajectory of a single liquid drop of sludge containing water, oil, and iron scale in a swirling high-temperature gas flow. Taking into account a two-phase transition area from liquid water to vapor, temperature fields in a drop are determined, as is an algorithm for calculating the movement trajectory of a drop in a swirling gas flow when heating it up according to a two-phase area of water evaporation. When designing a drying chamber for drops of scale- and oil-containing sludge, a mathematical model helps predict its typical size as well as control the drying process for drops produced by a disk atomizer.

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39

Zhou, Jun, Fenwu Liu e Chengyi Pan. "Effects of Cationic Polyacrylamide Characteristics on Sewage Sludge Dewatering and Moisture Evaporation". PLoS ONE 9, n. 5 (30 maggio 2014): e98159. http://dx.doi.org/10.1371/journal.pone.0098159.

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40

Velychko, Svitlana, e Olena Dupliak. "Assessment of the Influence of Evaporation and Evapotranspiration on the Volume of Sludge Accumulation in The Sludge Drying Beds". Journal of Ecological Engineering 22, n. 2 (1 febbraio 2021): 63–69. http://dx.doi.org/10.12911/22998993/130896.

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41

Ek, M., R. Bergström, J. E. Bjurhem, B. Björlenius e D. Hellström. "Concentration of nutrients from urine and reject water from anaerobically digested sludge". Water Science and Technology 54, n. 11-12 (1 dicembre 2006): 437–44. http://dx.doi.org/10.2166/wst.2006.924.

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Abstract (sommario):

Experiments with concentration of nutrients from source separated urine and reject water from digestion of sludge in sewage treatment plants (STP) have been performed in laboratory and pilot scale. The methods tested were membrane filtration with reverse osmosis (RO), evaporation, and precipitation of phosphorus and distillation of ammonia. In membrane filtration, pre-filtration with particle separation at 5–10 μm was enough to avoid clogging of the membranes. Separation of phosphorus (P), potassium (K) and sulphur (S) was almost 100%, while separation of nitrogen (N) was dependent on pH. The capacity of flux increased with temperature and pressure. In evaporation, all P, K and S were still in the concentrate, while pH had to be decreased to 4.5 to avoid significant loss of N. In precipitation and distillation, about 90% of P could be recovered from urine as magnesium ammonium phosphate (MAP) just by adding MgO. For the reject water pH was first increased by aeration to remove CO2. Ammonium can be distilled from the water phase after precipitation of MAP, without further increase of pH. At least 80–90% of N can be distilled in 5–10% of the total volume. The article also discusses the quality of different products, cost of separation, and energy and chemical demand.

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42

Mato, Fidel A., Mar Peña, Yoana García-Rodríguez, María-Dolores Bermejo e Ángel Martín. "Analysis of the Energy Flow in a Municipal Wastewater Treatment Plant Based on a Supercritical Water Oxidation Reactor Coupled to a Gas Turbine". Processes 9, n. 7 (17 luglio 2021): 1237. http://dx.doi.org/10.3390/pr9071237.

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Abstract (sommario):

Biological municipal wastewater treatments lead to high sludge generation and long retention times, and the possibilities for recovery of the energy content of the input waste stream are very limited due to the low operating temperature. As an alternative, we propose a sequence of exclusively physicochemical, non-biological stages that avoid sludge production, while producing high-grade energy outflows favoring recovery, all in shorter times. Ultrafiltration and evaporation units provide a front-end concentration block, while a supercritical water oxidation reactor serves as the main treatment unit. A new approach for energy recovery from the effluent of the reactor is proposed, based on its injection in a gas turbine, which presents advantages over simpler direct utilization methods from operational and efficiency points of view. A process layout and a numerical simulation to assess this proposal have been developed. Results show that the model process, characterized with proven operating parameters, found a range of feasible solutions to the treatment problem with similar energy costs, at a fast speed, without sludge production, while co-generating the municipality’s average electricity consumption.

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43

Lin, Ta-Hui, Annas Fauzy, Guan-bang Chen e Fang-Hsien Wu. "Utilization of Sewage Sludge Using Multiple Thermal Conversion Processes". Teknomekanik 4, n. 2 (27 dicembre 2021): 97–110. http://dx.doi.org/10.24036/teknomekanik.v4i2.11572.

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Sewage sludge is a usual waste from urban areas that can be utilized in many renewable energy sources. In this study, we examine the sewage sludge utilization using pyrolysis process to produce pyrolytic oil using Taguchi methods, combustion characteristic of sludge pyrolytic oil (SPO) blend with heavy fuel oil (HFO), and co-gasification of sewage sludge with CO2/steam as the gasification medium using Taguchi methods. The best-operating conditions for the pyrolysis of sewage sludge are a heating rate of 10oC/min, temperature of 450oC, the residence time of 60 min, and N2 flow rate of 700 mL/min. Under these conditions, the obtained pyrolytic oil yield is very close to the result from the Taguchi method calculation. In the combustion characteristic of sludge pyrolytic oil (SPO) blend with heavy fuel oil (HFO), a higher SPO in the fuel blend enhances the occurrence of micro-explosion and reduces the size of the residual. Higher SPO content in the fuel blend increases the combustion rate and increases the ignition delay due to moisture evaporation. In the co-gasification of sewage sludge and palm kernel shell optimization using Taguchi method, the best operational condition for maximum H2/ CO syngas ratio reaches at the gasification temperature of 900 C, a blending ratio of 30%, a CO2/(CO2+H2O) ratio of 70%, and a catalyst addition of 20% bed material mass. The best operating condition for maximum concentration of H2 reach with gasification temperature of 800 C, a blending ratio of 40%, a CO2/(CO2+H2O) ratio of 70%, and a 15% catalyst addition of bed material mass. The CO2/(CO2+H2O) ratio is the most important parameter among both case.

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44

Kujawiak, Sebastian, Małgorzata Makowska, Damian Janczak, Wojciech Czekała, Włodzimierz Krzesiński, Ariel Antonowicz e Karol Kupryaniuk. "An Analysis of the Physicochemical and Energy Parameters of Briquettes Manufactured from Sewage Sludge Mixtures and Selected Organic Additives". Energies 17, n. 18 (12 settembre 2024): 4573. http://dx.doi.org/10.3390/en17184573.

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Abstract (sommario):

As a by-product of wastewater treatment, sewage sludge can be used for natural, agricultural, or energy purposes. One method of preparing sludge for management and use is solar drying. To intensify the drying process, natural additives can be used to alter the structure of the sludge and accelerate the evaporation of water. This research aimed to evaluate the influences of different organic additives in sewage sludge mixtures on the physicochemical and energy parameters of briquettes. This research was carried out without thermal boosting in a 4 × 2.5 × 2 m plastic tunnel. The tunnel was equipped with three drying stations and control and measuring equipment. In two test series, sludge additives in the form of straw and lignocellulosic materials, sawdust, bark, woodchips, and walnut shells, were used. Briquettes were made from the resulting mixtures and then subjected to physical and chemical analyses. This research showed high variability in the contents of trace elements, nitrogen, and sulphur in relation to an increase in the amount of sludge in the briquettes, which, for the briquettes made from sewage sludge, was nearly twice as high as for the briquettes made from the mixtures. The results of the flue gas analysis for the briquettes with sawdust and wood chip additives were very similar. The briquettes made from sewage sludge with lignocellulosic materials (bark and wood chips) had fuel properties similar to woody biomass, with a calorific value and heat of combustion of 15–16 MJ/kg. Fibrous additives (straw) significantly increased the strength parameters of the briquettes, by more than 50% of the value. The compositions and properties of the mixtures affected the following briquetting parameters: temperature and compressive force. The briquettes made from sewage sludge and additives can be classified according to ISO 21640 as SRFs (solid recovered fuels). In most of the results, the net calorific value (NCV) was 3 to 4; the chlorine content (CL) was 2 to 1; and the mercury content (Hg) was 1. The sewage sludge mixtures facilitated the agricultural and energy use of the briquettes.

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45

Remington, Claire, Catherine Bourgault e Caetano C. Dorea. "Measurement and Modelling of Moisture Sorption Isotherm and Heat of Sorption of Fresh Feces". Water 12, n. 2 (22 gennaio 2020): 323. http://dx.doi.org/10.3390/w12020323.

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Abstract (sommario):

The drying (or dewatering) of fresh feces and fecal sludge is a productive step in the management of sanitation, waste treatment, and resource recovery services. An improved understanding of fresh feces and fecal sludge drying would contribute to the development and deployment of fecal sludge management services. However, there is a lack of available literature on the fundamental drying characteristics of fresh feces. In response to this gap, this work shares experimental results for equilibrium moisture content of fresh feces at different water activity levels (aw) and proposes the use of the Guggenheim, Anderson, and de Boer (GAB) model for predicting aw, calculating the heat of sorption, and estimating the corresponding energy requirements for drying of fresh feces. This is the first time this work has been done with fresh feces. The total heat of evaporation was significant up to a moisture content of about 0.2 kg water per kg dry solids. In addition to informing drying process design, the sorption isotherm can be used to predict microbial activity, which could improve the management of feces and fecal sludge from a public health perspective. These data in turn will be used to promote access to dignified, safe, and sustainable sanitation.

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46

Cai, Lu, Tong-Bin Chen, Ding Gao, Guo-Di Zheng, Hong-Tao Liu e Tian-Hao Pan. "Influence of forced air volume on water evaporation during sewage sludge bio-drying". Water Research 47, n. 13 (settembre 2013): 4767–73. http://dx.doi.org/10.1016/j.watres.2013.03.048.

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47

Larina, O. M., e V. M. Zaichenko. "Influence of pyrolysis on evaporation and solubility of heavy metals in sewage sludge". Journal of Physics: Conference Series 1556 (maggio 2020): 012017. http://dx.doi.org/10.1088/1742-6596/1556/1/012017.

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48

Cai, Lu, Ding Gao, Tong-Bin Chen, Hong-Tao Liu, Guo-Di Zheng e Qi-Wei Yang. "Moisture variation associated with water input and evaporation during sewage sludge bio-drying". Bioresource Technology 117 (agosto 2012): 13–19. http://dx.doi.org/10.1016/j.biortech.2012.03.092.

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49

Liu, Wei, Miao Gui, Yudong Zha e Zengyao Li. "Numerical Investigation of the Effect of Surface Wettability and Rotation on Condensation Heat Transfer in a Sludge Dryer Vertical Paddle". Energies 16, n. 2 (12 gennaio 2023): 901. http://dx.doi.org/10.3390/en16020901.

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Abstract (sommario):

In this paper, the applicability of advanced heat transfer enhancement technology to a paddle dryer was discussed. A computational fluid dynamics (CFD) method was used to simulate condensation heat transfer on the inner surface of a dryer paddle. The effect of surface wettability and rotation on condensation heat transfer and droplet behavior was studied. The results showed that the present CFD model could properly simulate the condensation process on a vertical surface. With a decrease in the contact angle, the filmwise condensation turned into a dropwise condensation, which resulted in a significant increase in heat transfer coefficient and provided an approximately 5% increase in evaporation rate for the paddle dryer by changing the wettability of the inner surface of the paddle. Additionally, with a change in rotational angular velocity, heat transfer performance was almost unchanged under the filmwise condensation condition. However, rotational motion might cause a decrease in wall temperature and the equivalent evaporation rate under the dropwise condensation condition. Only a 2.4% increase in the equivalent evaporation rate was found in dropwise condensation with rotation, which indicated that changing the wettability inside the paddle could not be an effective means to enhance the heat transfer and drying efficiency of a rotating paddle dryer.

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50

Samadiy, M. A., B. U. Abdullaev e I. I. Usmanov. "Technology for the production of potassium sulphate from mirabilite and potassium chloride of the Tyubegatan deposit". Proceedings of the National Academy of Sciences of Belarus, Chemical Series 59, n. 4 (2 dicembre 2023): 334–40. http://dx.doi.org/10.29235/1561-8331-2023-59-4-334-340.

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Abstract (sommario):

The results of studying the composition and rheological properties of solutions after separation of glaserite, as well as the influence of technological parameters on the process of evaporation of mother liquors in the production of potassium sulfate by conversion of flotation potassium chloride with mirabilite of the Tumryuk deposit, are presented. The evaporation process proceeds most intensively at 120 °C. In this case, after 60 minutes, the volume of the evaporated solution is reduced by 50 %. An increase in the volume of evaporated moisture from 20 to 40 % contributes to an increase in the sludge yield from 11.8 to 22.9 %. The density of solutions increases with an increase in the volume of evaporated liquid, and the viscosity slightly decreases. During evaporation, the density increases from 1.298 g/cm3 when 20 % moisture is removed to 1.358 g/cm3 when 40 % moisture is evaporated at a temperature of 20 °C. In this case, the viscosity decreases from 2.072 to 2.007 mPa·s. It is shown that at a ratio of glaserite sodium sulfate to potassium chloride equal to 1 : 1, a temperature of 30 °C and process duration of 40 minutes, the degree of conversion reaches 86.65 % in terms of potassium.

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