Effect of sludge cell disruption on compactibility of biological sludges

2000 ◽  
Vol 42 (9) ◽  
pp. 119-126 ◽  
Author(s):  
A. Erdincler ◽  
P. A. Vesilind
Keyword(s):  
Water Distribution ◽  
Interstitial Water ◽  
Alkali Treatment ◽  
Cell Structure ◽  
Solid Content ◽  
Cell Disruption ◽  
Water Release ◽  
Water Binding ◽  
Biological Sludge ◽  
Disruption Method

Biological sludge contains various fractions of water associated with sludge solids which are mostly microorganisms. These water fractions affect the liquid-solid separation of sludge. A considerable amount of sludge water is trapped either inside the sludge microorganisms or within the floc structure and this is labeled interstitial water. Release of interstitial water held inside the cell structure involves disruption of sludge cells and this does not occur during conventional dewatering. In this study, sludge cell disruption is introduced as a new method to improve the compactibility of sludge. Biological sludge cells are disrupted by different methods including alkali treatment, NaCl treatment, heat treatment, and sonication. The effect of cell disruption on compactibility of biological sludge is investigated. The results of the study indicate that the disruption of the sludge cells changes the water distribution in sludge and improves the compactibility of sludge. Disruption apparently releases from 60% to 80% of interstitial water, depending on the disruption method used. On the other hand, it causes creation of extra surfaces for water binding and leads to an increase in the unfreezable water content (vicinal water, water of hydration and a fraction of interstitial water) of sludge. The cell disruption increases the solid content of compacted sludge up to 87% depending on the cell disruption method used.

Influence d'un préconditionnement chimique sur l'épaississement gravitaire et la déshydratation de boues d'étangs aérés facultatifs

1995 ◽  
Vol 22 (6) ◽  
pp. 1198-1216
Author(s):  
Marc-André Desjardins ◽  
Charles Bussières ◽  
François G. Brière ◽  
Danielle Dagenais
Keyword(s):  
Key Words ◽  
Capture Rate ◽  
Great Difficulty ◽  
Solid Content ◽  
Cationic Polymers ◽  
Dual Effect ◽  
Biological Sludge ◽  
Gravity Thickening ◽  
Chemical Sludge

This article presents the results of a study on the influence of chemical preconditioning on gravity thickening and dewatering of biological and chemical sludge (alum dephosphatation sludge) from facultative aerated lagoons. Four reagents have been studied: two cationic polymers and two inorganic reagents. Inorganic reagents have not improved gravity thickening of sludge while polymers were more efficient. Polymers have a dual effect: they increase capture rate and accelerate solids settling. Biological sludge from lagoons thickens easily and may reach 10 to 12% dry solid contents, with or without the addition of polymers. On the contrary, chemical sludge thickens with great difficulty. Even with the addition of polymers, the maximum dry solid content did not reach more than 3.8% for sludge with initial dry solid content of 1.25% approximately. However, higher dry solid content can be obtained if the initial dry solid content of sludge is higher. Therefore, it is important to minimize dilution during the extraction of sludge from lagoons. Finally, the addition of polymers to sludge to help thickening does not affect the reconditioning of sludge to be dewatered except possibly in the case of mechanically dewatered chemical sludge treated with chemical conditioning. Key words: chemical preconditioning, gravity thickening, dewatering, sludge, facultative aerated lagoons.

Water-holding capacity and characterization of protein interactions in processed cheese

1995 ◽  
Vol 62 (3) ◽  
pp. 479-489 ◽  
Author(s):  
Sylvie Marchesseau ◽  
Jean-Louis Cuq
Keyword(s):  
Protein Interactions ◽  
Hydrophobic Interactions ◽  
Visual Assessment ◽  
Protein Protein Interactions ◽  
Water Release ◽  
Water Binding ◽  
Processed Cheese ◽  
Protein Gels ◽  
Higher Temperature ◽  
Water Holding

SummaryIn order to predict the oozing susceptibility of heat-induced milk protein gels such as processed cheeses during storage, ultracentrifugation forces are required to accelerate the expulsion of water from the gel structure. Two predictive methods have been tested. Direct ultracentrifugation of processed cheese was used to study effects of centrifugal compression on the water-holding ability. The water release with optimal parameters (time, temperature and ultracentrifugation force) from a freshly manufactured processed cheese was correlated with visual assessment of oozing after 6 months storage. A second method was based on the susceptibility of gelled proteins to resist the dissociating action of solutions of chemical agents such as SDS, urea, EDTA and 2-mercaptoethanol. Most of the protein sedimented by ultracentrifugation in the presence of SDS represented that still in complexed form. This correlated with optimal water binding by the processed cheese. Response-surface methods, used to optimize the ultracentrifugation variables and the composition of the dissociation solutions, showed that the dissociation test was best with a dispersion of processed cheese in SDS solution (10 g/l) at a ratio of 1:6 (w/v) at 20°C, ultracentrifuged at 86000 g and 20°C for 25 min. Analysis of processed cheese cooked at 115°C and then dissociated in different solutions showed various protein–protein interactions in the gel network, whereas hydrophobic interactions were the most important stabilizers of the protein matrix of cheese cooked at higher temperature.

Prediction of full-scale dewatering results of sewage sludges by the physical water distribution

2001 ◽  
Vol 43 (11) ◽  
pp. 135-143 ◽  
Author(s):  
J. Kopp ◽  
N. Dichtl
Keyword(s):  
Sewage Sludge ◽  
Water Content ◽  
Water Distribution ◽  
Free Water ◽  
Full Scale ◽  
Water Release ◽  
Total Solids ◽  
Solids Concentration ◽  
Free Water Content ◽  
Sludge Cake

The dewaterabilty of sewage sludge can be described by the total solids concentration of the sludge cake and the polymer-demand for conditioning. The total solids concentration of the sludge cake depends on the physical water distribution. The various types of water in sewage sludge are mainly distinguished by the type and the intensity of their physical bonding to the solids. In a sewage sludge suspension four different types of water can be distinguished. These are the free water, which is not bound to the particles, the interstitial water, which is bound by capillary forces between the sludge flocs, the surface water, which is bound by adhesive forces and intracellular water. Only the share of free water can be separated during mechanical dewatering. It can be shown, that by thermo-gravimeteric measurement of the free water content, an exact prediction of full-scale dewatering results is possible. By separation of all free water during centrifugation the maximum dewatering result is reached. Polymer conditioning increases the velocity of the sludge water release, but the free water content is not influenced by this process. Furthermore it is not possible, to replace the measuring of the water distribution by other individual parameters such as ignition loss.

Evaluation of cell disruption method for lipase extraction from novel thraustochytrids

2017 ◽  
Vol 25 ◽  
pp. 62-67 ◽  
Author(s):  
Avinesh R. Byreddy ◽  
Nalam Madhusudhana Rao ◽  
Colin J. Barrow ◽  
Munish Puri
Keyword(s):  
Cell Disruption ◽  
Disruption Method

scholarly journals Measurement and Modelling of Moisture Distribution and Water Binding Energy of Dredged Sludge

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3395
Author(s):  
Feiyan Mao ◽  
Yingjie Zhao ◽  
Yiping Zhang ◽  
Zhou Chen ◽  
Lu Yin
Keyword(s):  
Binding Energy ◽  
Water Distribution ◽  
Bound Water ◽  
Free Water ◽  
Moisture Distribution ◽  
Water Binding ◽  
Dredged Sludge ◽  
Urban Watercourse ◽  
Experimental Values ◽  
Stage 1

The dewatering of dredged sludge is a critical step in the minimization and reutilization of this solid waste. However, there is a lack of available literature on the fundamental drying characteristics of dredged sludge. In this work, two kinds of typical sludge dredged from an urban watercourse were tested by low-field NMR to investigate the water distribution in sludge and it was found that water contained in sludge can be classified into three categories: free water, capillary water and bound water. In addition, a novel model was proposed based on the Lennard-Jones equation and Kelvin law to quantitatively evaluate the binding energy during drying. Further, the model results were experimentally verified by thermogravimetry differential thermal analysis (TG-DTA). Results show that the trends of the model are consistent with the experimental values and the gradient of energy consumption during dehydration can be divided into three main stages. In stage 1, the total energy required for dewatering equals the latent heat of free water. In stage 2, binding energy reaches dozens to hundreds of kJ/kg accounting for capillary action. In stage 3, binding energy increases steeply reaching almost thousands of kJ/kg due to intermolecular interactions. All the discovered aspects could improve the management and disposal of dredged sludge from an energy cost perspective.

scholarly journals Current Pretreatment/Cell Disruption and Extraction Methods Used to Improve Intracellular Lipid Recovery from Oleaginous Yeasts

2021 ◽  
Vol 9 (2) ◽  
pp. 251
Author(s):  
Muhammad Fakhri Zainuddin ◽  
Chong Kar Fai ◽  
Arbakariya B. Ariff ◽  
Leonardo Rios-Solis ◽  
Murni Halim
Keyword(s):  
Solvent Extraction ◽  
Osmotic Shock ◽  
Extraction Methods ◽  
Resistant Cell ◽  
Cell Disruption ◽  
Systematic Evaluation ◽  
Green Solvents ◽  
Oleaginous Yeasts ◽  
Disruption Method ◽  
Recovery Methods

The production of lipids from oleaginous yeasts involves several stages starting from cultivation and lipid accumulation, biomass harvesting and finally lipids extraction. However, the complex and relatively resistant cell wall of yeasts limits the full recovery of intracellular lipids and usually solvent extraction is not sufficient to effectively extract the lipid bodies. A pretreatment or cell disruption method is hence a prerequisite prior to solvent extraction. In general, there are no recovery methods that are equally efficient for different species of oleaginous yeasts. Each method adopts different mechanisms to disrupt cells and extract the lipids, thus a systematic evaluation is essential before choosing a particular method. In this review, mechanical (bead mill, ultrasonication, homogenization and microwave) and nonmechanical (enzyme, acid, base digestions and osmotic shock) methods that are currently used for the disruption or permeabilization of oleaginous yeasts are discussed based on their principle, application and feasibility, including their effects on the lipid yield. The attempts of using conventional and “green” solvents to selectively extract lipids are compared. Other emerging methods such as automated pressurized liquid extraction, supercritical fluid extraction and simultaneous in situ lipid recovery using capturing agents are also reviewed to facilitate the choice of more effective lipid recovery methods.

scholarly journals THE DETERMINATION OF SALINITY AND NUTRITION (NaH2PO4) PROFILE IN Nannochloropsis oculata CULTIVATION TO GAIN MAXIMUM LIPID

REAKTOR ◽  
2012 ◽  
Vol 14 (2) ◽  
pp. 135
Author(s):  
Elida Purba ◽  
Kenjiro Siburian
Keyword(s):  
Total Lipid ◽  
Lipid Content ◽  
Nannochloropsis Oculata ◽  
Cell Disruption ◽  
Disruption Method

The determination of salinity and nutrition (NaH2PO4) profile in Nannochloropsis oculata cultivationto gain maximum lipid was investigated. The purpose of this research was to determine the optimumsalinity and nutrition (NaH2PO4) to gain maximum lipid in Nannochloropsis oculata. Phosphor canbe obtained by adding NaH2PO4 and a salinity enhancement can be applied by adding NaCl to theculture. This research was run by matching each variable of salinity (33, 34, 35, and 36 ppt) to eachvariable of NaH2PO4 (5, 10 and 15 ppm) randomly. The results show that the percentage of maximumlipid in Nannochloropsis oculata was obtained at 35 ppt and 5 ppm NaH2PO4 (37.68 %). Neverthelessthe maximum lipid percentage is low and it can be caused by some factors, such as the dryingtemperature for preparing the dry microalgae to extract, the cell disruption method and the extractionsolvent used. By seeing the results, salinity can affect the total lipid in Nannochloropsis oculata. Thegreater the salinity in culture the greater the lipid content in Nannochloropsis oculata. Otherwise adifferent response was obtained by adding NaH2PO4. If NaH2PO4 concentration is greater, the lipidcontained Nannochloropsis oculata will be lower Penentuan profilsalinitas dan nutrisi (NaH2PO4) pada pembiakan Nannochloropsis oculata untuk memperoleh lipidmaksimum diteliti. Tujuan penelitian ini adalah untuk menentukan salinitas dan nutrisi (NaH2PO4)optimum untuk memperoleh lipid maksimum pada Nannochloropsis oculata. Fosfor dapat diperolehdengan menambahkan NaH2PO4 pada kultur dan peningkatan salinitas dapat dilakukan denganmenambahkan NaCl pada kultur. Penelitian ini dijalankan dengan mencocokkan setiap variabelsalinitas (33, 34, 35, dan 36 ppt) dengan setiap variabel NaH2PO4 (5, 10 dan 15 ppm) secara acak.Hasil menunjukkan bahwa persentase lipid maksimum pada Nannochloropsis oculata diperoleh padasalinitas 35 ppt dan 5 ppm NaH2PO4 (37,68 %). Walaupun demikian, persentase lipid maksimummasih tergolong rendah dan hal ini dapat disebabkan oleh beberapa faktor, seperti temperaturpengeringan yang diterapkan, metode cell disruption dan pelarut ekstraksi yang digunakan. Denganmempelajari hasil yang telah didapat, salinitas dapat mempengaruhi lipid total padaNannochloropsis oculata. Semakin tinggi salinitas pada biakan, semakin tinggi kandungan lipid padaNannochloropsis oculata. Sebaliknya didapatkan respon yang berbeda saat menambahkan NaH2PO4.Apabila konsentrasi NaH2PO4 semakin tinggi, maka lipid yang terkandung pada Nannochloropsisoculata akan menjadi lebih rendah.

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