Water Content Determinations for Peat and Other Organic Soils Using the Oven-Drying Method

O’Kelly, Brendan C.; Sivakumar, V.

doi:10.1080/07373937.2013.849728

Cited by 85 publications

(44 citation statements)

References 32 publications

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“…Similar behaviour (i.e. Geotechnics of municipal sludges and residues for landfilling O'Kelly strength heterogeneity) has been reported for peat deposits on account of non-uniform rates of decomposition on-site (Landva, 1980a;O'Kelly and Pichan, 2013;O'Kelly and Sivakumar, 2014).…”

Section: Undrained Strength Requirements For Landfillingmentioning

confidence: 75%

“…For routine water content determinations on organic soils, standardised oven-drying temperature ranges of 110 ± 5°C (ASTM, 2014) or 105-110°C (BSI, 1990a) specified for the testing of inorganic soils should be consistently used (Hobbs, 1986;O'Kelly, 2014b;O'Kelly and Sivakumar, 2014;Skempton and Petley, 1970) in conjunction with a 24-h drying period and minimum wet specimen mass of 50 g (O'Kelly and Sivakumar, 2014).…”

Section: Methodsmentioning

confidence: 99%

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Geotechnics of municipal sludges and residues for landfilling

O’Kelly

2016

Geotechnical Research

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This paper presents a comprehensive review of reported field and laboratory investigations and theoretical work concerning the geotechnical behaviour/properties of water treatment residue (WTR), biosolids and sewage sludge materials, which are by-products of municipal water and wastewater treatment processes. After describing the backgrounds to the generation of these materials and various disposal options (with a focus on landfilling), including associated geotechnical issues, their physical, geotechnical index, compaction, undrained strength and effective-stress strength properties are described, including the effects of oxidation, biodegradation and viscous gellike pore fluid for biosolids/sewage sludge material. Characteristic compressibility, consolidation and permeability behaviour/properties are also presented for these materials and linked with microstructure and the chemicals added during the treatment processes. The paper then focuses on various geotechnical issues pertinent to landfill (monofill) disposal of these materials, including undrained strength requirements, design strength, on-site and laboratory strength measurements and water content-strength correlations. Since such correlations are material specific, with the geotechnical properties of biosolids, sewage sludge and WTR materials varying between water/wastewater treatment plants, they cannot be applied more widely with confidence. Alternative approaches to predicting undrained strength are described, including a power-law strength relationship with water content, which can be applied more generally. , 2008a). The type and amount of chemicals added depends on the nature of the source water, but primarily on its turbidity and hardness. The coagulants cause the colloidal particles present to aggregate into flocs (with the polyelectrolyte also acting as a binding agent to increase their inherent shear strength) that are more readily separated out by settling processes, removing not only the impurities but also the chemical additives. NotationThe residue so formed is categorised as aluminium sulfate (alum) or iron WTR material depending on the coagulant salt, with the former being the most widely used coagulant in the water treatment industry. Lime-softening sludge, composed of typically 80-95 wt% calcite (Raghu and Hsieh, 1986), is the result of softening hard water before its distribution as drinking water.Biosolids and sewage sludge materials are highly organic residue by-products of municipal waste water treatment, with the organic fraction originating principally from human faeces (primary sludge) and bacterial biomass (secondary sludge) and the inorganic fraction derived from materials such as soil, sediment and inorganic residuals (Haynes et al., 2009). According to the US Environmental Protection Agency (EPA) (2015), sewage sludge refers to the solids separated out during the treatment processes, whereas biosolids refers to treated sewage sludge material that meets regulatory pollutant-and pathogen-control requirements for land applica...

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Section: Undrained Strength Requirements For Landfillingmentioning

confidence: 75%

Section: Methodsmentioning

confidence: 99%

Geotechnics of municipal sludges and residues for landfilling

O’Kelly

2016

Geotechnical Research

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“…The moisture content of drying sample at any time 14 was transformed to the moisture ratio (MR) using Eq. [2] (12,15) t 0 MM MR MM [2] Where M t is the moisture content at any time of drying (kg water/kg dry basis); M 0 is the initial moisture content (kg water/kg db) and M e is the equilibrium moisture content (kg water/kg db).…”

Section: Drying Kineticsmentioning

confidence: 99%

Influence of blanching treatment and drying methods on the drying characteristics and quality changes of dried sardine (Sardinella gibbosa) during storage

et al. 2016

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The aim of this study was to examine the drying characteristics of blanched and unblanched sardine during indoor and open sun drying processes. Changes in temperature and relative humidity of the air during drying were recorded. The colour, peroxide value (PV), thiobarbituric acid reactive substances (TBARS), free fatty acid (FFA) content, fatty acid composition and sensory attributes of dried samples were also evaluated once a month for 5 months of storage. High drying rates were obtained in all samples at the start of drying and then decreased with increasing drying time. The highest drying rate and effective water diffusivity (D eff ) were observed in blanched sardine during open sun drying. Blanching treatment slowed down the FFA progression during products storage but adversely affected the colour, PV and TBARS content as well as sensory properties. Although sardine dried for a longer time under indoor drying conditions, it attained a stable moisture ratio that was lower than in open sun dried samples. Indoor drying produced a quality stable product with less lipid oxidation products and the desired moisture content, higher polyunsaturated fatty acids and sensory properties. Blanching Downloaded by [University of Birmingham] at 06:03 25 June 20162 treatment negatively affected the fish quality and is therefore not recommended for commercial sardine drying.

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“…For peat classification, the type of parent vegetation should always be reported, either by using terms such as 'moss peat' or 'grass peat' or, preferably, by referring to the predominant plant type(s) present -for example, Sphagnum peat or sedge peat (Farrell, 2012;Helenelund, 1967;O'Kelly, 2015a). The water content, organic content, fibrosity, degree of humification and (dry) density should also be included in the classification for geomechanical purposes, with the standard oven-drying temperature range of 105-110°C used for water content determinations on inorganic soils also appropriate for routine water content determinations on fibrous peat materials (O'Kelly and Sivakumar, 2014;Skempton and Petley, 1970). In many cases, however, tested peats are poorly described (often only the water content and loss on ignition values are given), making comparisons between reported geomechanical properties for different peat materials investigated difficult.…”

Section: Botanical Composition Degree Of Humification and Strength Pmentioning

confidence: 99%

“…It is hoped that this work will contribute to the overall understanding of this topic, including the best way forward for determining the pertinent undrained and effective-stress strength properties of peat materials. However, it should be kept in mind the great spatial variability in engineering properties and fibrosity of peat deposits (Hobbs, 1986;Landva and Pheeney, 1980;O'Kelly and Sivakumar, 2014). Although not the subject of this paper, it is also useful to determine the soil parameter values for geotechnical designs by using in situ tests and geophysical techniques that can measure pertinent soil parameters continuously to the required depth (e.g.…”

mentioning

confidence: 99%

Measurement, interpretation and recommended use of laboratory strength properties of fibrous peat

O’Kelly

2017

Geotechnical Research

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Peat deposits are complex natural formations encountered in many geographical areas. Peat itself is considered as a challenging geomaterial, with many aspects of its behaviour seemingly remaining enigmas. This state-of-the-art review paper provides an extensive summary of current knowledge on the strength and shear behaviour of fibrous peats. Critical assessments and interpretations of the undrained strength, effective-stress strength and at-rest earth pressure coefficient parameter values determined for fibrous peat materials using standard and advanced laboratory apparatus are presented, focusing particularly on the consolidated undrained triaxial compression and direct simple shear approaches. Based on documented case histories of embankments, dikes and natural peat slopes, guidance is given for operational shear strength assessments in peat, aimed at bearing capacity and slope stability calculations, considering both the normalised undrained strength ratio and limit equilibrium effective-stress strength approaches. In particular, the botanical origin, structural anisotropy, humification level, likely initial overconsolidated state, tensile resistance associated with the peat fibres and possible scale effect related to the test-specimen size are discussed in the context of the strength mobilised for different testing apparatus. The test methodologies and interpretations of experimental results presented for fibrous peat in this paper should be transferable to other fibrous soil and soil-like materials. Notation

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Water Content Determinations for Peat and Other Organic Soils Using the Oven-Drying Method

Cited by 85 publications

References 32 publications

Geotechnics of municipal sludges and residues for landfilling

Geotechnics of municipal sludges and residues for landfilling

Influence of blanching treatment and drying methods on the drying characteristics and quality changes of dried sardine (Sardinella gibbosa) during storage

Measurement, interpretation and recommended use of laboratory strength properties of fibrous peat

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