DSC and SEM Analysis on Bound Water Characteristics in Sewage Sludge

2011 ◽  
Vol 347-353 ◽  
pp. 2085-2089 ◽  
Author(s):  
Wei Yun Wang ◽  
Ai Min Li ◽  
Xiao Min Zhang
Keyword(s):  
Liquid Phase ◽  
Sewage Sludge ◽  
Moisture Content ◽  
Differential Scanning Calorimeter ◽  
Bound Water ◽  
Water Structure ◽  
Sem Analysis ◽  
Water Characteristics ◽  
Water Based ◽  
Calculation Results

Water structure present in sewage sludge with different moisture content was analyzed by differential scanning calorimeter(DSC).The sharp endothermic peaks that appeared at 6.14°C(95.87%wet basis),5.22°C(87.20%wet basis),1.33°C(71.20%wet basis).The calculation results , amount of bound water based on peak temperature and peak area, could account for stick phase of sewage sludge combined with SEM analysis results. Finally,mechanical mechanism of different phases(liquid phase, sticky phase, granule phase) were tentively described by schematic diagrams.

Experimental Study on Hydrothermal Treatment of Municipal Sewage Sludge

2013 ◽  
Vol 448-453 ◽  
pp. 693-698 ◽  
Author(s):  
Li Li Qian ◽  
Shu Zhong Wang ◽  
Xing Ying Tang
Keyword(s):  
Sewage Sludge ◽  
Moisture Content ◽  
Hydrothermal Treatment ◽  
Initial Moisture Content ◽  
Bound Water ◽  
High Energy ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Gravimetric Analysis ◽  
Combustion Performance

Wastewater treatment plants produced large amounts of municipal dewatered sewage sludge with about 80wt% moisture content. High moisture content is the bottleneck of sludge treatment and disposal. Hydrothermal treatment could economically disrupt sludge cells, release bound water and finally improve sludge dewaterability instead of thermal drying technology with high energy consumption. In this paper, hydrothermal treatment experiments were carried out and the combustion performance of the original sewage sludge and the hydrothermal treatment sewage sludge was analyzed to verify the possibility of burning after sludge hydrothermal treatment. The results show that the optimal reaction temperature, initial moisture content, pressure and time are 170°C, 87wt%, 0.9MPa and 40min, respectively, obtaining a final moisture content lower than 50wt% by centrifugation. Total Organic Carbon (TOC) results show that higher temperature and pressure, as well as longer reaction time are of benefit to the hydrothermal treatment of the municipal sewage sludge. Furthermore, Thermal Gravimetric Analysis (TGA) of the original sewage sludge and the hydrothermal treatment sewage sludge shows that a hydrothermal treatment can improve the combustion performance of the sludge, which is beneficial to the subsequent incineration process.

Dewatering of Sewage Sludge Using Thermal Compression

2012 ◽  
Vol 193-194 ◽  
pp. 89-93 ◽  
Author(s):  
Li Fan ◽  
Ming Yuan Zhou ◽  
Xiu Li Li
Keyword(s):  
Sewage Sludge ◽  
Moisture Content ◽  
Bound Water ◽  
Solid Content ◽  
Mechanical Compression ◽  
Sludge Dewatering ◽  
Sludge Management ◽  
Thermal Compression ◽  
Traditional Process

Mechanical compression is a traditional process for the dewatering of sewage sludge. However, the moisture content of the cake is still high, unfavorable for the sludge management. In this paper, the use of thermal compression to improve the sludge dewatering is investigated. The dewatering efficiency is affected by the applied temperature, pressure and the sludge mass. The bound water of the sludge is further reduced by thermal compression, improving the dewatering performance. The solid content of the cake obtained after 10 min mechanical compression and 60 min thermal compression at 120 oC and 4 MPa is 85.2%.

Estimation of Energy Saving for Melting Process on Sewage Sludge

1991 ◽  
Vol 23 (10-12) ◽  
pp. 2011-2018 ◽  
Author(s):  
T. Murakami ◽  
K. Sasabe ◽  
K. Sasaki ◽  
T. Kawashima
Keyword(s):  
Sewage Sludge ◽  
Moisture Content ◽  
Energy Saving ◽  
Fuel Consumption ◽  
Melting Process ◽  
System Operation ◽  
Operational Conditions ◽  
Volatile Solids ◽  
Cake Moisture ◽  
Very High

The possible volume reduction and stabilization of the sewage sludge associated with the melting process are expected to be greater than with the incineration process. In addition, melted slag can be utilized. However, since the melting process requires a very high temperature to melt inorganics (ash) in the sludge, the technologies to minimize energy consumption, to establish system operation and to prolong durability of facilities should be developed. This paper discusses the auxiliary fuel consumption as follows.(1)Preparation of a model that provides the auxiliary fuel consumption of the melting system on the basis of the mass and heat balances.(2)Evaluation of the auxiliary fuel consumption in the above model using the cake moisture content, the volatile solids of the cake, the dried cake moisture content and the melting temperature as parameters.(3)Examination of the operational conditions for an energy saving melting system based on the results of (1) and (2) above.

scholarly journals Sewage Sludge Treatment by Hydrothermal Carbonization: Feasibility Study for Sustainable Nutrient Recovery and Fuel Production

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2697
Author(s):  
Gabriel Gerner ◽  
Luca Meyer ◽  
Rahel Wanner ◽  
Thomas Keller ◽  
Rolf Krebs
Keyword(s):  
Liquid Phase ◽  
Sewage Sludge ◽  
Hydrothermal Carbonization ◽  
Economic Feasibility ◽  
Phosphorus Recovery ◽  
High Yield ◽  
Nutrient Recovery ◽  
Waste Biomass ◽  
Sludge Treatment ◽  
Sewage Sludge Treatment

Phosphorus recovery from waste biomass is becoming increasingly important, given that phosphorus is an exhaustible non-renewable resource. For the recovery of plant nutrients and production of climate-neutral fuel from wet waste streams, hydrothermal carbonization (HTC) has been suggested as a promising technology. In this study, digested sewage sludge (DSS) was used as waste material for phosphorus and nitrogen recovery. HTC was conducted at 200 °C for 4 h, followed by phosphorus stripping (PS) or leaching (PL) at room temperature. The results showed that for PS and PL around 84% and 71% of phosphorus, as well as 53% and 54% of nitrogen, respectively, could be recovered in the liquid phase (process water and/or extract). Heavy metals were mainly transferred to the hydrochar and only <1 ppm of Cd and 21–43 ppm of Zn were found to be in the liquid phase of the acid treatments. According to the economic feasibility calculation, the HTC-treatment per dry ton DSS with an industrial-scale plant would cost around 608 USD. Between 349–406 kg of sulfuric acid are required per dry ton DSS to achieve a high yield in phosphorus recovery, which causes additional costs of 96–118 USD. Compared to current sewage sludge treatment costs in Switzerland, which range between 669 USD and 1173 USD, HTC can be an economically feasible process for DSS treatment and nutrient recovery.

scholarly journals Synchrotron radiation macromolecular crystallography: our science and spin offs

2014 ◽  
Vol 70 (a1) ◽  
pp. C10-C10
Author(s):  
John Helliwell
Keyword(s):  
Synchrotron Radiation ◽  
Protein Complexes ◽  
Bound Water ◽  
Water Structure ◽  
Public Understanding ◽  
Anomalous Scattering ◽  
Structural Studies ◽  
Macromolecular Crystallography ◽  
Time Resolved ◽  
Chemical Crystallography

I will give an overview of synchrotron radiation (SR) in macromolecular crystallography (MX) instrumentation, methods and applications from the early days to the present, including the evolution of SR sources and on to the `ultimate storage ring'. The build of dedicated beamlines for resonant anomalous scattering, large unit cells, ever smaller crystals and studies up to ultra-high resolution are core benefits. Results include a high output of PDB depositions, the successful use of microcrystals, pushing the frontiers of using high and low photon energies and time-resolved structural studies at even sub-nanosecond resolutions. These intensively physics based developments will be complemented by biological and chemical crystallography research results, encompassing catalysis and marine coloration, as well as the public understanding of our science and its impacts. Spin off benefits include services to the pharmaceutical industry and helping develop chemical crystallography uses of SR. The development of the Laue method with SR has led to pioneering spin off developments in neutron MX, including transfer of the well validated Daresbury Laue software to various neutron facilities worldwide. Neutron MX is gathering pace as new instrumentation and dedicated sample preparation facilities are in place at reactor and spallation neutron sources; smaller samples and much larger molecular weight protein complexes are now feasible for investigation so as to establish their protonation states and bound water structure. With the X-ray lasers, closely linked to the SR developments, we anticipate the use of ever smaller samples such as nanocrystals, nanoclusters and single molecules, as well as opening up femtosecond time-resolved diffraction structural studies. At the SR sources, a very high throughput assessment for the best crystal samples and tackling sub-micron crystals will become widespread.

scholarly journals Study on the Moisture Absorption and Thermal Properties of Hygroscopic Exothermic Fibers and Related Interactions with Water Molecules

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 98 ◽  
Author(s):  
Yi Cui ◽  
Shuyi Gao ◽  
Ruiyun Zhang ◽  
Longdi Cheng ◽  
Jianyong Yu
Keyword(s):  
Moisture Content ◽  
Thermal Performance ◽  
Water Sorption ◽  
Moisture Absorption ◽  
Bound Water ◽  
Absorption Process ◽  
Heating Performance ◽  
Hygroscopic Behavior ◽  
Water Sorption Capacity ◽  
Main Factor

The aim of this paper is to study the hygroscopic behavior of hygroscopic exothermic fiber-based materials and to obtain a better understanding of the thermal performance of these fibers during the moisture absorption process. The temperature distribution of different kinds of hygroscopic exothermic fibers in the process of moisture absorption, observed by infrared camera, demonstrated two types of heating performance of these fibers, which might be related to its hygroscopic behavior. Based on the sorption isotherms, a Guggenheim-Anderson-de Boer (GAB) multi-layer adsorption model was selected as the optimal moisture absorption fitting model to describe the moisture absorption process of these fibers, which illustrated that water sorption capacity and the water–fiber/water–water interaction had a significant influence on its heating performance. The net isosteric heats of sorption decreased with an increase of moisture content, which further explained the main factor affecting the heat dissipation of fibers under different moisture contents. The state of adsorbed water and water vapor interaction on the fiber surface were studied by simultaneous thermal analysis (TGA-DSC) measurement. The percentage of bound and unbound water formation at low and high humidity had a profound effect on the thermal performance of fibers. It can therefore be concluded that the content of tightly bound water a strong water–fiber interaction was the main factor affecting the heating performance of fibers at low moisture content, and the content of loosely bound water reflected that water sorption capacity was the main factor affecting the heating performance of fibers at high moisture content. This was further proven by the heat of desorption.

Determine the Moisture Distribution in Sewage Sludge by Drying Differential

2014 ◽  
Vol 665 ◽  
pp. 404-407 ◽  
Author(s):  
Wan Yu ◽  
Pei Sheng Li
Keyword(s):  
Sewage Sludge ◽  
Interstitial Water ◽  
Bound Water ◽  
Free Water ◽  
High Accuracy ◽  
Moisture Distribution ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
Hot Air ◽  
Critical Water Content

Moisture distribution in sewage sludge was considered as the essential of thermal drying. Some methods were given in literatures to test the moisture distribution, but there was no standard method to determine the critical water content between different kinds of water. The municipal sewage sludge was dried by hot air in this work. Based on the drying curve, the derivative of drying rate with respect to dry basis moisture content was brought out to analyze the moisture distribution in sewage sludge. Results show that this method can easily determine the free water, interstitial water, surface water and bound water with a high accuracy. The present work can provide new insight to determine the moisture distribution in sewage sludge, which was still lacking in the literatures.

Entrapment, stability, and persistence of air bubbles in soil water

Soil Research ◽  
1969 ◽  
Vol 7 (2) ◽  
pp. 79 ◽  
Author(s):  
AJ Peck
Keyword(s):  
Hydraulic Conductivity ◽  
Moisture Content ◽  
Soil Water ◽  
Unsaturated Soils ◽  
Equilibration Time ◽  
Air Bubbles ◽  
Air Entrapment ◽  
Water Characteristics ◽  
Spherical Bubbles ◽  
Entrapped Air

Air bubbles in soil water affect both hydraulic conductivity and moisture content at a given capillary potential. Consequently changes in the volume of entrapped air, which are not included in the specification of relationships between hydraulic conductivity, moisture content, and capillary potential, will affect all soil-water interactions. Current understanding of the process of air bubble entrapment during infiltration suggests that, in nature, significant air entrapment will often occur. It is shown that infiltrating water can dissolve only a very small volume of air, much less than the amount usually entrapped. Air bubbles in saturated soils are unstable since their pressure must exceed atmospheric, resulting in a diffusive flux of dissolved air from bubbles to menisci contacting the external atmosphere. However, stable bubbles are possible in unsaturated soils. Bubbles which are constrained by pore architecture to non-spherical shapes are usually stable, and spherical bubbles can be stable when the magnitude of the capillary potential exceeds about 3 bars. An approximate analysis of the characteristic time of bubble equilibration indicates that, in an example, it is of order 104 sec, but it may be greater or less by at least a factor 10. Since the equilibration time will be often at least as large as the period of significant soil temperature changes, it cannot be assumed that the entrapped air in a field soil is in an equilibrium state. In such circumstances unstable bubbles may be quasi-permanent. It is suggested that the slow growth of entrapped bubbles may account for the anomalously slow release of water observed in some outflow experiments. Changes of entrapped air volume may also account for the reported dependence of soil-water characteristics on the magnitude of the steps of capillary potential.

The Influence of Ferrous Metallurgy Waste in the Aktobe Region on the Frost Resistance of Ceramic Bricks Based on Low-Melting Clay

2021 ◽  
Vol 887 ◽  
pp. 453-459
Author(s):  
A.K. Kairakbaev ◽  
E. S. Abdrakhimova ◽  
V.Z. Abdrakhimov
Keyword(s):  
Liquid Phase ◽  
Moisture Content ◽  
Firing Temperature ◽  
Frost Resistance ◽  
Glass Phase ◽  
Raw Materials ◽  
Residual Moisture ◽  
Chromite Ore ◽  
Alkali Oxides ◽  
Pass Through

The research objective is studying the effect of tailing slurry of chromite ore beneficiation on the phase composition and frost resistance of ceramic bricks obtained based on low-melting clay. For the study, two compositions were taken, % wt.: 1) the optimal composition ─ low-melting clay of the Ilek deposit - 70, tailing slurry of chromite ore beneficiation, 2) the reference composition ─ low-melting clay of the Ilek deposit - 100. Raw materials were crushed to pass through a sieve No. 1.0 mm; then, the components were thoroughly mixed. The bricks were prepared by melting at a batch moisture content of 22 %. The mold bricks were dried to a residual moisture content of 5 % max. The dried bricks were fired at temperatures, оС: 950 (the glass phase emergence), and 1,050 (the final brick firing temperature). The increased content of iron oxide (Fe2O3=12.3 %) and alkali oxides (R2O=3.2 %) in the tailing slurry of chromite ore beneficiation contributed to the liquid phase emergence at 950 оС. Colorless, yellowish, and brown glasses with refractive indices N within 1.50-1.54, forming as a result of melting of spars and mixed-layer clayey formations, were observed under the microscope in the studied prototypes of composition No. 1 at a firing temperature of 950 °C. In the composition No. 2, a liquid phase also emerges, but in smaller quantities. Adding tailing slurry of chromite ore beneficiation to ceramic masses contributes to the formation of anorthite and glass phase in prototypes based on low-melting clay at a firing temperature of 950 °C. An increase in the firing temperature to 1,050 °C increases the content of the glass phase and anorthite, which significantly improves the frost resistance of ceramic bricks.

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