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.

A tensammetric study of the adsorption of cationic polymers and copolymers

1991 ◽  
Vol 69 (10) ◽  
pp. 1516-1519
Author(s):  
Truis Smith-Palmer ◽  
Cheryl Roberts
Keyword(s):  
Molecular Weight ◽  
Charge Density ◽  
Key Words ◽  
Potential Versus ◽  
Cationic Polymers ◽  
Capacitive Current ◽  
Cationic Polyacrylamide

The tensammograms of several sets of cationic polyacrylamide copolymers are discussed and compared. Tensammograms are not affected by molecular weight, but plots of capacitive current at a chosen potential versus charge density give regular curves. Key words: tensammetry, cationic, polyacrylamide, charge density.

Il muro di Padova: un muro di solida paura

2009 ◽  
pp. 91-109
Author(s):  
Michela Morello ◽  
Rosj Camarda
Keyword(s):  
Local Government ◽  
Key Words ◽  
Solid Content ◽  
Drug Dealing ◽  
Urban Policies ◽  
Extreme Measure ◽  
Neighbouring Area ◽  
The City

- The Padua Wall: a Wall of Solid Fear, If there is a lucky relevance in the concept of liquid fear, it is the physical image of what, not having a solid content, slides over, trickles through chinks and floods any surface that comes across. If applied to a specific case, the concept materialises in its solid ambivalence. In the Padua case under examination, the municipality makes the choice, explosive from a communication perspective, to par8 tially isolate - with an iron fence, the so-called wall - an inhabited area, considered out of control because of the growing flow of regular and irregular immigrants, of crime episodes, of drug dealing, of acts of intolerance by some of the residents. The area will be evacuated due to a serious sanitary emergence, the residents of that compound will be transferred in smaller groups in other buildings in the city. The fear of residents of the neighbouring area to find drug dealers in their homes will fade away. The solidity of an extreme measure will stay, as well as having indicated a solution in front of a failure, that is what terrifies most people. Key words: local government, urban policies, security strategies.

Improvement of the thickening and dewatering characteristics of activated sludge by electroflotation (EF)

2005 ◽  
Vol 52 (10-11) ◽  
pp. 219-226 ◽  
Author(s):  
Y.G. Choi ◽  
H.S. Kim ◽  
Y.H. Park ◽  
S.H. Jeong ◽  
D.H. Son ◽  
...  
Keyword(s):  
Water Quality ◽  
Activated Sludge ◽  
Solid Content ◽  
Laboratory Scale ◽  
Volume Reduction ◽  
Air Bubbles ◽  
Effluent Water ◽  
Gravity Thickening

The performances of electroflotation (EF) on the thickening of activated sludge were investigated using laboratory scale batch flotation reactors. Four activated sludges including bulking sludges were tested. After 30minutes of EF operation, 57–84% of sludge volume reduction could be achieved by EF, while only about 1.5–14% could be obtained by gravity thickening for the same period. After thickening the effluent water quality in terms of TCOD, SS, and turbidity was improved by EF operation for all sludge samples. In addition, the EF thickened sludge showed much better dewaterability both in SRF and cake solid content. It is induced that the air bubbles entrapped in the thickened sludge play a key role in the observed dewaterbility improvement.

Iron Phosphate and Anaerobic Digestion

1970 ◽  
Vol 5 (1) ◽  
pp. 102-128
Author(s):  
A. Grikis ◽  
G.M. Cornwall
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Iron Phosphate ◽  
Phosphorus Concentration ◽  
Batch Reactors ◽  
Biological Sludge ◽  
Soluble Phosphorus ◽  
Chemical Sludge ◽  
Biological Component ◽  
Expected Increase

Abstract This research was undertaken in order to clarify some of the apparent inconsistencies in the literature concerning the fate of phosphates in iron phosphate sludges during anaerobic digestion. Three anaerobic batch reactors were started and acclimatized to a feed of waste activated sludge. While one digester was maintained as a control, with a feed of only biological sludge, the other two digesters were loaded with different mixtures of biological sludge and iron phosphate sludge. When the digesters had stabilized with respect to influent and effluent total phosphorus, critical measurements of all the phosphorus fractions were made. The soluble phosphorus in the control digester remained the same from the influent to the effluent. This observation seems to contradict the expected increase in soluble phosphates during the anaerobic digestion process. When the activated sludge was mixed with the ferric phosphate sludge, it was observed that a reduction in soluble phosphorus took place. After this combined biological-chemical sludge had been digested anaerobically, an increase in the soluble phosphorus concentration, to a level roughly equivalent to that in the biological component of the influent, was observed.

Conditionnement et déshydratation de boues d'étangs aérés facultatifs à l'aide du gel – dégel naturel: résultats d'essais

1996 ◽  
Vol 23 (2) ◽  
pp. 323-339 ◽  
Author(s):  
Marc-André Desjardins ◽  
François G. Brière
Keyword(s):  
Suspended Solids ◽  
Winter Season ◽  
Oxygen Demand ◽  
Solid Content ◽  
Thin Layers ◽  
Freeze Thaw ◽  
Storage Basin ◽  
Low Levels ◽  
High Chemical Oxygen Demand ◽  
Chemical Sludge

This article presents the results of tests investigating the conditioning and dewatering of biological and chemical sludge (alum dephosphatation sludge) from facultative aerated lagoons using natural freeze–thaw. The results presented here highlight the excellent efficiency of this conditioning method used with drying beds. Following freeze–thaw, immediately after drainage, sludge presents little odor and has lost its liquid state since dry solid contents of more than 30% can be obtained with ease. Freeze–thaw also eliminates the gelatinous consistency of chemical sludge. The filtrates are clear and contain low levels of suspended solids but may have relatively high chemical oxygen demand. To maximize the depth of sludge that can be frozen, it is necessary to freeze the sludge in thin layers. This requires the pumping of sludge from a separate storage basin to a freezing bed for the duration of winter (separate basin–bed method). The storage basin may however be combined with the freezing bed provided the depth of the sole sludge layer does not exceed the maximum depth of sludge that can be frozen during the winter season (combined basin–bed method). Freeze–thaw is not affected by the initial dry solid content of the sludge. The grain size of the sludge can however have some influence, although quite marginal, and freeze–thaw is efficient for all types of aqueous sludge. Key words: conditioning, dewatering, sludge, facultative aerated lagoons, natural freeze–thaw, trials.

scholarly journals Treatment of PCBs Contaminated Soil Via Aerobic Vermicomposting Process Amended with Biological Sewage Sludge

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Nima Eslami ◽  
Afshin Takdastan ◽  
Farideh Atabi
Keyword(s):  
Contaminated Soil ◽  
Contaminated Soils ◽  
Volume Ratio ◽  
Solid Content ◽  
Biological Sludge ◽  
Volatile Solids ◽  
Soils And Sediments ◽  
Plant Operations ◽  
Living Organisms ◽  
Ph Level

Background: During power plant operations, significant amounts of (PCBs)-contaminated soil are generated. PCBs enter the environment in various forms, causing toxicity in humans and other living organisms. Various technologies are used to remove PCBs from contaminated soils and sediments. Objectives: Bioremediation is an environmentally friendly method to improve areas infected with PCBs. In this study, to decontaminate PCB-contaminated soil, the effect of biological sludge in contaminated soil on the removal of PCBs was investigated in a vermicomposting process at different mix ratios. Methods: Mixtures of PCB-contaminated soil and biological sludge were prepared in sample containers at different mix ratios, and then, earthworms were added. Over 80 days, besides the reduction of PCBs, pH, volatile solid content, and fixed solid content changes were also examined. Results: The highest reduction in PCBs (47.4%) was reported in pilot D at a contaminated soil-to-biological sludge volume ratio of 1:4. Moreover, in the same pilot, the pH level decreased from 7.9 to 7.2, indicating a further decline compared to other pilots, attributed to the further reduction of volatile solids. The highest reduction in volatile solids occurred in pilot D, decreasing from 74.8% at the beginning of the experiment to 42.9% at the end. The largest amount of mineralization also occurred in the same pilot. Conclusions: In this study, it was found that Eisenia fetida worms, along with microorganisms in the biological sludge, could function properly at all volume ratios of contaminated soil to biological sludge and could purify contaminants in a vermicomposting process.

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.

scholarly journals KETAHANAN PAPAN KOMPOSIT DARI LIMBAH KAYU SENGON DAN KARTON TERHADAP RAYAP KAYU KERING DAN RAYAP TANAH

PERENNIAL ◽  
2008 ◽  
Vol 4 (1) ◽  
pp. 28
Author(s):  
. Suhasman ◽  
Muh. Yusram Massijaya ◽  
Yusuf Sudo Hadi ◽  
Astuti Arif
Keyword(s):  
Key Words ◽  
Infection Rate ◽  
Solid Wood ◽  
Solid Content ◽  
Subterranean Termite ◽  
Paraserianthes Falcataria ◽  
Composite Board ◽  
Resin Solid ◽  
Water Based ◽  
Materials Used

This study was aimed to analyze the resistance of composites board made from wafer and carton or paper overlaid on drywood termite and subterranean termite. Materials used in this study were wafer from sengon wood (Paraserianthes falcataria L. Nielsen), water based polymer isocyanate adhesive, veneer, and several kind of carton and paper such as duplex carton, recycle carton, corrugate board, and waste of cement sack. The target density was 0.65 g/cm3, while the resin solid content was 6%. The result of this study showed that no significantly different on infection rate of drywood termite among of composite board types and solid wood. The weight loose of composites board were 1.2–3.8%, while solid wood was 2.7%. Composites board more favorable to infection Macrotermes gilvus than solid wood. The weight loose of composites board were 19.3 – 28.8%, while solid wood was 12.6%. Key words: Composites board, drywood termite, subterranean termite

Joint Treatment of Industrial Effluent: Case Study of Limassol Industrial Estate

1994 ◽  
Vol 29 (9) ◽  
pp. 99-104 ◽  
Author(s):  
I. Hadjivassilis ◽  
L. Tebai ◽  
M. Nicolaou
Keyword(s):  
Biological Treatment ◽  
Industrial Effluent ◽  
Treatment Plant ◽  
Biological Sludge ◽  
Sludge Stabilization ◽  
Industrial Estate ◽  
Treated Effluent ◽  
Chemical Sludge

The treatment plant has been designed and installed for the treatment of wastewater discharged from various industries at Limassol Industrial Estate. The total daily flow and biological load after the last extension of the plant are 1000-1200m3/d and 220-264kg BOD5/d respectively. Chemical treatment followed by biological treatment is applied. The main steps of the treatment process are as follows: equalization, flotation, coagulation-flocculation, settlement of chemical sludge, pH-adjustment, nutrient addition, aeration of activated sludge, settlement of biological sludge, chlorination and sludge stabilization. The efficiency of the plant with respect to BOD5 and COD removal is over 90%. The quality of the treated effluent is BOD5 < 15mg/l and COD < 40mg/l. The concentration of trace elements are below the recommended limits for reclaimed water used for irrigation purposes.

Comparative Microstructures of Ion Milled and Electrochemically Thinned Composite Materials

1974 ◽  
Vol 32 ◽  
pp. 546-547
Author(s):  
R.R. Russell
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Composite Materials ◽  
Great Difficulty ◽  
Ion Milling ◽  
Transmission Electron ◽  
Ion Damage ◽  
Intermetallic Composite

Transmission electron microscopy of metallic/intermetallic composite materials is most challenging since the microscopist typically has great difficulty preparing specimens with uniform electron thin areas in adjacent phases. The application of ion milling for thinning foils from such materials has been quite effective. Although composite specimens prepared by ion milling have yielded much microstructural information, this technique has some inherent drawbacks such as the possible generation of ion damage near sample surfaces.

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