Influence of the free water content on the dewaterability of sewage sludges

Kopp, J.; Dichtl, Norbert

doi:10.2166/wst.2001.0613

Cited by 65 publications

(21 citation statements)

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“…On the other hand, the digestion of WAS resulted in a gradual deterioration of sludge dewatering parameters during the initial stage of digestion, but at the end of the process, the detriment in dewaterability is striking, reaching a CST value of more than 2000 s. Even though the mean particle size of WAS and U_WAS digestates presented similar values, the dewatering behavior of digestates varied significantly (Table 3). Drying curves and water distribution as interpreted by Kopp and Dichtl [23] are shown in Figure 3. Three zones are described: free water associated with solid particles, interstitial water (trapped inside interstitial spaces of flocs and microorganisms), and chemically bound water.…”

Section: Dewatering Parameters During the Digestion Processmentioning

confidence: 99%

Effect of Ultrasound Pretreatment on Sludge Digestion and Dewatering Characteristics: Application of Particle Size Analysis

Martínez

Rosas

Morán

et al. 2015

Water

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Abstract:The aim of this work was to study the effect of ultrasonic pretreatment on sludge digestion, particle size distribution (PSD), and dewaterability of digestates (measured by capillary suction time (CST) and specific resistance to filtration (SRF)). Sludge was pretreated with ultrasound (24 kHz) at an energy dosage of 4300 kJ/kg TS. Digestibility of sludge was increased by ultrasound pretreatment resulting in a higher specific methane production (SMP). The digestate of pretreated waste activated sludge (WAS) obtained under batch conditions presented a better dewatering performance. Digestion under semi-continuous conditions was evaluated using sewage sludge (mixture of primary sludge and WAS). In this case, digestates presented a much higher mean particle size for both cases evaluated (pretreated and non-pretreated) than that obtained under batch conditions. A wide PSD was a characteristic of these digestate samples. Flow dynamics inside the reactor resulted in the presence of high-diameter flocs, thus significantly affecting the mean particle size and specific surface area (SSA) values.

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Section: Dewatering Parameters During the Digestion Processmentioning

confidence: 99%

Effect of Ultrasound Pretreatment on Sludge Digestion and Dewatering Characteristics: Application of Particle Size Analysis

Martínez

Rosas

Morán

et al. 2015

Water

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“…Several researches (Kopp and Dichtl, 2001;Tsang and Vesilind, 1990) have distinguished four categories of water in sewage sludge according to the bond form between the moisture and sludge particle: free water, interstitial water, surface water, and chemically bound water. So far, most of the studies (Baroutian et al, 2013; Baudez et al, 2011;Pevere et al, 2006) about the influence of TS content on the rheological behaviours of sludge were carried out by concentrating or diluting with water, which could only influence the amount of free water and interstitial water but the bound water content might not be affected.…”

Section: The Influence Of Srt and Temperature Of Reactor On The Digesmentioning

confidence: 99%

Rheology evolution of sludge through high-solid anaerobic digestion

Dai

Gai

Dong

2014

Bioresource Technology

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“…The water distribution can be derived from the curve of the drying rate in relation to the moisture content of the sample (Kopp & Dichtl 2001).…”

Section: Hydraulic Measurementsmentioning

confidence: 99%

Sludge drying reed beds: full- and pilot-scale study for activated sludge treatment

Troesch¹,

Liénard²,

Molle³

et al. 2009

Water Science and Technology

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Sludge drying reed beds have been used for dewatering and mineralization of sludge since the beginning of the 90s, but their insufficient performances in terms of Dry Matter [DM] content and mineralization of the sludge have made necessary new studies. Therefore, 8 pilots of 2 m2 each and a full-scale plant (13,000 p.e, 8 beds of 470 m2 in operation for 4 years) have been monitored to examine the influence of the sludge loading rate, the sludge quality and the loading frequency on the dewatering and mineralization efficiencies. Two filtration layers and two loading rhythms were tested on pilots which were fed at a loading rate of 25-30 kg DM m(-2) yr(-1) during the first year of operation (commissioning period). Hydraulic behaviour (infiltration rate, outflow), O2 and CO2 relative concentrations in the filtration media, redox potential, pollutants removal and dry matter content were assessed during all the study. The rheological quality of the extracted sludge from full scale beds was assessed and showed that its mechanical behaviour exceed those of sludge of comparable dry matter content, making its spreading easier. Therefore, this sludge could easily claim the status of solid and stabilized sludge according to the French regulation. Design and management recommendations (number of beds, loading rates, feeding/rest period) gained from the experiments results are suggested.

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Influence of the free water content on the dewaterability of sewage sludges

Cited by 65 publications

References 0 publications

Effect of Ultrasound Pretreatment on Sludge Digestion and Dewatering Characteristics: Application of Particle Size Analysis

Effect of Ultrasound Pretreatment on Sludge Digestion and Dewatering Characteristics: Application of Particle Size Analysis

Rheology evolution of sludge through high-solid anaerobic digestion

Sludge drying reed beds: full- and pilot-scale study for activated sludge treatment

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