Freeze–thaw treatment of RBC sludge from a remote mining exploration facility in subarctic Canada

Diak, James; Örmeci, Banu; Proux, Corinne

doi:10.2166/wst.2011.376

Cited by 27 publications

(6 citation statements)

References 11 publications

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“…Örmeci and Vesilind (2001) showed that F/T conditioning was more effective for chemical sludges (alum sludge) than biological sludges, with high concentrations of dissolved organic matter and ions negatively affecting the F/T process, possibly by promoting particle entrapment during freezing. This is confirmed in several F/T pilot studies reporting various DM content of the dewatered sludge: 17% DM for a rotating biological contactor sludge (Diak et al 2011), 25% DM for waste activated sludge (WAS) and 39% DM for an anaerobic digestion (AD) sludge (Martel and Diener 1991) and 82% DM for alum sludge (Martel 1993).…”

Section: Introductionsupporting

confidence: 55%

Modelling and application of an uncovered freezing bed technology for septage treatment

2012

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A series of pilot scale freezing bed experiments were conducted to evaluate and model the freeze-thaw treatment of septic tank sludge (septage). Filtrate quality is similar to a low strength domestic wastewater and the sludge cake has a dry matter content of 25% with E. coli numbers below 2.0 × 10 6 CFU/g dry solids. Experimental results showed no impact of snow cover on bed performance in a region with moderate snowfall (1.3-1.6 m) as new layers of sludge effectively melted any accumulated snow; suggesting that it is not necessary to cover the bed or remove the snow in areas where sludge dosing exceeds snowfall. Both freezing and thawing processes were successfully modelled with readily available climatic data. Model output for North American climatic conditions indicates that the freezing bed technology can be widely applied throughout the northern United States and Alaska and most of Canada with the exception of coastal areas and southern Ontario.Résumé : Une série d'expériences à l'échelle pilote de lit de congélation a été réalisée pour évaluer et modéliser le traitement par gel-dégel des boues de fosses septiques. La qualité du filtrat est similaire aux eaux usées domestiques de faible intensité et le gâteau de boues possède un contenu en matières sèches de 25 % et un nombre d'E. coli sous les 2.0 × 10 6 CFU/g de solides secs. Les résultats expérimentaux ont montré que la couverture de neige n'avait aucun impact sur la performance du lit dans une région présentant des chutes de neige modérées (1,3 à 1,6 m) alors que les nouvelles couches de boues faisaient fondre toute accumulation de neige, suggérant qu'il n'est pas nécessaire de couvrir le lit ni de retirer la neige dans les zones ou le dosage de boues excède les chutes de neige. Les processus de gel et de dégel ont été modélisés avec succès en utilisant des données climatiques facilement disponibles. Les données générées par le modèle pour les conditions climatiques nord-américaines indiquent que la technologie du lit de congélation peut être largement appliquée partout aux États-Unis et en Alaska et dans la plus grande partie du Canada, à l'exception des zones côtières et du sud de l'Ontario.

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Section: Introductionsupporting

confidence: 55%

Modelling and application of an uncovered freezing bed technology for septage treatment

2012

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“…Introduction of thermal WAS pretreatment in previous years aimed at improving the degree of mineralisation of sludge as well as its dewatering (Örmeci 2004; Diak et al 2011). The dewatering of sewage sludges with the use of freezing takes place through separation of solid and liquid fractions during the formation of ice crystals.…”

Section: Resultsmentioning

confidence: 99%

Waste-activated sludge disruption by dry ice: bench scale study and evaluation of heat phase transformations

Machnicka

Grűbel

Sikora

2019

Environ Sci Pollut Res

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The freezing process consists of dissipating heat from the product until the final temperature is lower than the temperature of crystallisation of that product. Freezing can be used for numerous applications, including for disruption of waste-activated sludge (WAS). The aim of this study was to calculate the estimated amount of heat conveyed between the solidified carbon dioxide and the WAS, in the following ratios: 0.25:1; 0.5:1; 0.75:1 and 1:1. In heat of phase transformations, dry ice sublimation, water solidification, the amount of heat transferred by other substances and heat transferred from the sludge (dry sludge) were taken into account during the process of WAS freezing. Heat changes on the surface of WAS were registered using a thermovision camera. The effectiveness of WAS disintegration was confirmed by several biochemical parameters such as soluble chemical oxygen demand (increase over 14 times), degree of disintegration (48%), proteins (increase over 5 times), carbohydrates (increase almost 7 times), RNA (increase by 2.23 mg L−1), ammonia nitrogen (increase over 23 times), phosphates (increase almost 27 times) and turbidity (increased over 7 times). It was found that dry ice pretreatment of WAS can be an intriguing alternative for the conventional methods used.Electronic supplementary materialThe online version of this article (10.1007/s11356-019-05889-2) contains supplementary material, which is available to authorized users.

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“…The water state distributions and water state changes that were found throughout the experiment are presented in Figure 3. The water state clearly changed between 0 d and 2 d in all of the composting treatments, and this may have been caused by the effects of thawing the original waste materials, which had been stored at −20 ∘ C, leading to some of the frozen water in the stored material becoming liquid water in the waste mixture used in the composting treatments [27]. This liquid water would have been classed as EW during the water state testing procedure, so the waste mixtures would have had high EW contributions to the MC on day 0.…”

Section: Effect Of the C/n Ratio On Changes In The Water Statesmentioning

confidence: 99%

Effect of C/N on Water State during Composting of Kitchen Waste and Vegetable Waste Mixture

Liu

Yang

et al. 2017

Journal of Chemistry

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The objective of this study was to evaluate the effects of the C/N ratio on the water state changes during the composting of kitchen waste (KW) and vegetable waste (VW) mixtures. The C/N ratios in KW and VW were 50.70 and 27.07, respectively, and the VW was added to the KW to amend the C/N ratio. Five composting treatments were used, R1 with 0% KW, R2 with 25% KW, R3 with 50% KW, R4 with 75% KW, and R5 with 100% KW, and the initial C/N ratios increased in the order R1 < R2 < R3 < R4 < R5. As the composting process progressed, the capillary water (CW) and multi-molecular-layer water (MMLW) were changed into entrapped water (EW), and a high C/N ratio could delay the changes in the water state. The percentage of EW and CW significantly positively correlated with the C/N ratio during the composting of KW. The composting process performed better in treatments R2 and R3 than in the other treatments, and it was found that treatments R2 and R3 each had a lag phase of around 4 d until the water states started to change.

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Freeze–thaw treatment of RBC sludge from a remote mining exploration facility in subarctic Canada

Cited by 27 publications

References 11 publications

Modelling and application of an uncovered freezing bed technology for septage treatment

Modelling and application of an uncovered freezing bed technology for septage treatment

Waste-activated sludge disruption by dry ice: bench scale study and evaluation of heat phase transformations

Effect of C/N on Water State during Composting of Kitchen Waste and Vegetable Waste Mixture

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