Municipal wastewater sludge dewaterability and the presence of microbial extracellular polymer

2001 ◽  
Vol 44 (2-3) ◽  
pp. 373-379 ◽  
Author(s):  
J. J. Houghton ◽  
J. Quarmby ◽  
T. Stephenson
Keyword(s):  
Municipal Wastewater ◽  
Extraction Process ◽  
Wastewater Sludge ◽  
Optimum Level ◽  
Wastewater Treatment Process ◽  
Capillary Suction ◽  
Sludge Dewaterability ◽  
The Uk ◽  
The Relationship ◽  
Extracellular Polymer

Dewatering of sewage sludge is an essential and costly part of the wastewater treatment process. The presence of microbial extracellular polymer (ECP) is important for sludge flocculation, but ECP has also been shown to have a detrimental effect on the dewaterability of certain sludge types. This paper investigates the relationship between sludge dewaterability and the level of ECP present in a range of sludges obtained from 8 full-scale municipal treatment works in the UK. Sludge dewaterability was determined using the capillary suction time (CST) test, and a thermal extraction process followed by solvent precipitation was used for ECP extraction. The results indicate that for each type of sludge examined there appears to be an optimum level of ECP (raw sludge 20 mg ECP/g SS; activated sludge 35 mg ECP/g SS; digested sludge 10 mg ECP/g SS) at which the sludge should exhibit maximum dewaterability. The establishment of a trend between sludge dewaterability and the quantity of ECP present opens up the possibility of manipulating the level of microbial polymer present to aid sludge dewatering, and hence reduce plant operating costs.

scholarly journals Sensitivity analysis of a municipal wastewater treatment plant model

2019 ◽  
Vol 252 ◽  
pp. 05010
Author(s):  
Paweł Król ◽  
Alberto Gallina ◽  
Michał Lubieniecki ◽  
Tadeusz Uhl ◽  
Tadeusz Żaba
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Treatment Process ◽  
Biological Process ◽  
Treatment Plant ◽  
Numerical Procedure ◽  
Municipal Wastewater Treatment ◽  
Wastewater Treatment Process ◽  
Plant Model ◽  
The Relationship

Waste management is a crucial process to keep the environment in wholesome conditions. The environmental impact of solid waste and wastewater is reduced through construction of appropriate disposal installations. The objective of wastewater treatment in biological reactors is to control the process of biomaterial growth by aerating the sewage content. The process is complex, as depending on a plenty of parameters. In the last decades an effective numerical model, called the Activated Sludge Model (ASM), has been proposed for describing the biological process. The ASM is implemented in the Benchmark Simulation Model (BSM) that simulates the whole wastewater treatment process. The most important parameters in ASM are the kinetic and stoichiometric coefficients. The former describes rate-concentration dependence. The latter characterises the relationship between the components of chemical reactions taking place in the cleaning process. Above parameters are determined by on-site calibration and their importance is relevant during the development of numeric models. This paper aims to examine the influence of kinetic and stoichiometric parameters on the wastewater treatment process of a plant in Płaszów, Kraków. The analysis is carried out by a sample-based numerical procedure. It highlights the ASM parameters playing a major role in the treatment process. Results obtained from the analysis are important for future validation and optimisation processes.

Effect of centrifugation on the removal of extracellular polymers and physical properties of activated sludge

1994 ◽  
Vol 30 (8) ◽  
pp. 117-127 ◽  
Author(s):  
F. Dilek Sanin ◽  
P. Aarne Vesilind
Keyword(s):  
Activated Sludge ◽  
Physical Properties ◽  
Inorganic Materials ◽  
Extracellular Polymers ◽  
Capillary Suction ◽  
The Past ◽  
Main Components ◽  
The Relationship ◽  
Flocculated Suspension ◽  
Extracellular Polymer

Activated sludge is a flocculated suspension of living and dead microorganisms enmeshed together in a polymer matrix along with some organic and inorganic materials. Extracellular polymers, main components of which are the polysaccharides, proteins, and nucleic acids, act as a protective barrier to the living microbial community, and give the floc its integrity and rigidity. These polymers have been found to affect the dewatering and settling characteristics of activated sludge. Even though they were studied considerably in the past there is not a complete understanding of the relationship between the amount of polymer and changes in the physical properties of sludge. The purpose of this research is to observe the effects of centrifugal force on the extraction of the extracellular polymers from an activated sludge and to correlate the amount of polymer extracted to the subsequent physical properties of the sludge. Centrifugal forces of 2000, 5000, 8000, 11,000, 14,000, and 16,500 G were tested for their effects on the amount of extracellular polymer collected, as well as the final properties of sludge like viscosity, filterability, compactability and supernatant turbidity. Results were evaluated in comparison to those of an uncentrifuged control waste activated sludge. Removal of extracellular polymers seems to affect the viscosity of activated sludge. Filterability, as measured by the capillary suction time instrument, was affected by the extraction of polymers to a great degree. Results of the independent tests correlated well with each other and with the amount of polymers extracted. Results of this study have important implications on sludge pumping and dewatering.

Anaerobic co-digestion of municipal wastewater sludge with food waste with different fat, oil, and grease contents: study of reactor performance and extracellular polymeric substances

RSC Advances ◽  
2015 ◽  
Vol 5 (125) ◽  
pp. 103547-103556 ◽  
Author(s):  
Rui Xu ◽  
Zhaohui Yang ◽  
Ting Chen ◽  
Lijun Zhao ◽  
Jing Huang ◽  
...  
Keyword(s):  
Microbial Activity ◽  
Food Waste ◽  
Extracellular Polymeric Substances ◽  
Municipal Wastewater ◽  
Wastewater Sludge ◽  
Reactor Performance ◽  
Oil And Grease ◽  
The Relationship

The relationship between extracellular polymeric substances and microbial activity was investigated in three groups of fat, oil, and grease (FOG)-enhanced ACoD reactors.

Thromboplastin Related Differences in the Determination of International Normalised Ratio: A Cause for Concern?

1994 ◽  
Vol 72 (03) ◽  
pp. 426-429 ◽  
Author(s):  
S Kitchen ◽  
I D Walker ◽  
T A L Woods ◽  
F E Preston
Keyword(s):  
Patient Management ◽  
External Quality Assessment ◽  
Oral Anticoagulant Therapy ◽  
Warfarin Dosage ◽  
External Quality ◽  
External Quality Assessment Scheme ◽  
International Normalised Ratio ◽  
The Uk ◽  
The Relationship

SummaryWhen the International Normalised Ratio (INR) is used for control of oral anticoagulant therapy the same result should be obtained irrespective of the laboratory reagent used. However, in the UK National External Quality Assessment Scheme (NEQAS) for Blood Coagulation INRs determined using different reagents have been significantly different.For 18 NEQAS samples Manchester Reagent (MR) was associated with significantly lower INRs than those obtained using Diagen Activated (DA, p = 0.0004) or Instrumentation Laboratory PT-Fib HS (IL, p = 0.0001). Mean INRs for this group were 3.15, 3.61, and 3.65 for MR, DA, and IL respectively. For 61 fresh samples from warfarin-ised patients with INRs of greater than 3.0 the relationship between thromboplastins in respect of INR was similar to that observed for NEQAS data. Thus INRs obtained with MR were significantly lower than with DA or IL (p <0.0001). Mean INRs for this group were 4.01, 4.40, and 4.59 for MR, DA, and IL respectively.We conclude that the differences between INRs measured with the thromboplastins studied here are sufficiently great to influence patient management through warfarin dosage schedules, particularly in the upper therapeutic range of INR. There is clearly a need to address the issues responsible for the observed discrepancies.

Researching (with) Major Food Retailers

2015 ◽  
Vol 15 (3) ◽  
pp. 33-39 ◽  
Author(s):  
David Evans
Keyword(s):  
Food Systems ◽  
Academic Research ◽  
Social Scientists ◽  
Major Food ◽  
Food Retailers ◽  
Food Retailer ◽  
The One ◽  
The Uk ◽  
The Relationship ◽  
Opening Up

This paper considers the relationship between social science and the food industry, and it suggests that collaboration can be intellectually productive and morally rewarding. It explores the middle ground that exists between paid consultancy models of collaboration on the one hand and a principled stance of nonengagement on the other. Drawing on recent experiences of researching with a major food retailer in the UK, I discuss the ways in which collaborating with retailers can open up opportunities for accessing data that might not otherwise be available to social scientists. Additionally, I put forward the argument that researchers with an interest in the sustainability—ecological or otherwise—of food systems, especially those of a critical persuasion, ought to be empirically engaging with food businesses. I suggest that this is important in terms of generating better understandings of the objectionable arrangements that they seek to critique, and in terms of opening up conduits through which to affect positive changes. Cutting across these points is the claim that while resistance to commercial engagement might be misguided, it is nevertheless important to acknowledge the power-geometries of collaboration and to find ways of leveling and/or leveraging them. To conclude, I suggest that universities have an important institutional role to play in defining the terms of engagement as well as maintaining the boundaries between scholarship and consultancy—a line that can otherwise become quite fuzzy when the worlds of commerce and academic research collide.

Physical properties of dewatered wastewater sludge for landfilling

1996 ◽  
Vol 34 (3-4) ◽  
pp. 533-540 ◽  
Author(s):  
A. Koenig ◽  
J. N. Kay ◽  
I. M. Wan
Keyword(s):  
Shear Strength ◽  
Hong Kong ◽  
Municipal Wastewater ◽  
Compressibility Factor ◽  
Wastewater Sludge ◽  
Municipal Wastewater Treatment ◽  
Intrinsic Resistance ◽  
Coefficient Of Consolidation ◽  
Minimum Requirement ◽  
Geotechnical Stability

In the context of landfilling dewatered wastewater sludge in Hong Kong, with landfills up to 140 m high, one of the most significant properties of sludge is its physical nature with regard to moisture characteristics and associated geotechnical stability. Commonly, lower limits are set on total solids content, but no geotechnical stability criteria are applied with the exception of Germany where a minimum requirement for vane shear strength is set at 25 kN/m2. The purpose of this study was to determine and evaluate dewatered wastewater sludge from three Hong Kong municipal wastewater treatment plants with regard to the following physical and geotechnical properties: (i) vane shear strength; (ii) consolidation characteristics such as compression index, compressibility factor, coefficient of consolidation and compressibility coefficient; and (iii) hydraulic characteristics such as permeability and intrinsic resistance. Although dewatered sludge exhibits quite different characteristics as compared to soils, predictive logarithmic relationships may be established between various properties which are consistent with the critical state model for soils, conventional filtration and consolidation theory. Such representation provides a valuable basis for understanding the sludge characteristics and behaviour to landfill design.

Archaeologists and the Dead

2016 ◽  
Keyword(s):  
Historical Context ◽  
Ethical Considerations ◽  
International Context ◽  
The Public ◽  
The Us ◽  
The Dead ◽  
The Many ◽  
The Uk ◽  
The Relationship ◽  
Experience Effect

This volume addresses the relationship between archaeologists and the dead, through the many dimensions of their relationships: in the field (through practical and legal issues), in the lab (through their analysis and interpretation), and in their written, visual and exhibitionary practice--disseminated to a variety of academic and public audiences. Written from a variety of perspectives, its authors address the experience, effect, ethical considerations, and cultural politics of working with mortuary archaeology. Whilst some papers reflect institutional or organizational approaches, others are more personal in their view: creating exciting and frank insights into contemporary issues that have hitherto often remained "unspoken" among the discipline. Reframing funerary archaeologists as "death-workers" of a kind, the contributors reflect on their own experience to provide both guidance and inspiration to future practitioners, arguing strongly that we have a central role to play in engaging the public with themes of mortality and commemoration, through the lens of the past. Spurred by the recent debates in the UK, papers from Scandinavia, Austria, Italy, the US, and the mid-Atlantic, frame these issues within a much wider international context that highlights the importance of cultural and historical context in which this work takes place.

Hydrothermal liquefaction of municipal wastewater sludge and nutrient recovery from the aqueous phase

Biofuels ◽  
2021 ◽  
pp. 1-6
Author(s):  
Vinod Kumar ◽  
Krishna Kumar Jaiswal ◽  
Mikhail S. Vlaskin ◽  
Manisha Nanda ◽  
M. K. Tripathi ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Municipal Wastewater ◽  
Hydrothermal Liquefaction ◽  
Wastewater Sludge ◽  
Nutrient Recovery
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