Investigation of sewage sludge stabilization potential by the addition of fly ash and lime

Samaras, P.; Papadimitriou, C.A.; Haritou, I.; Zouboulis, Anastasios

doi:10.1016/j.jhazmat.2007.11.012

Cited by 121 publications

(57 citation statements)

References 27 publications

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“…High pH has been widely used as an indicator of biochemical stabilisation because a pH >11 leads to the immobilisation of heavy metals, the destruction of pathogens and lowering of microbial activity (Bednarik et al, 2004;Samaras et al, 2008). Conversely, a decline in pH can lead to a surge in the biodegradation of organic matter.…”

Section: Compactionmentioning

confidence: 99%

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: Compactionmentioning

confidence: 99%

Geotechnics of municipal sludges and residues for landfilling

O’Kelly

2016

Geotechnical Research

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“…The findings of Placha et al showed that after the lime hydrated addition the pH of mixture increased to 12.12 ± 0.02, and the Salmonella spp, strain was devitalized in 60 minutes (22 (1,13,24). If fertilizer consumption of waste sludge were considered, the microbiological quality of the product must be enhanced up to class A of USEPA criteria (20,(25)(26)(27)(28)(29). Upgrading the management of waste sludge is a fundamental step for the expansion of an integrated approach for the management of wastewater.…”

Section: Discussionmentioning

confidence: 99%

Lime Stabilization of Waste Activated Sludge

Farzadkia

Bazrafshan

2014

Health Scope

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Background: Sewage sludge (Biosolids) is a byproduct of wastewater treatment that accumulates in large quantities. Effective stabilization and disinfection of sewage sludge prior to land application are necessary to not only protect human health, but also to induce the public its benefits and safety. Currently, many wastewater treatment plants in Iran dispose great amounts of untreated sewage sludge to the environment. Objectives: The purpose of this work was to upgrade wastewater treatment plants by lime stabilization of waste sludge. Materials and Methods: Lime stabilization of waste sludge from Shoosh wastewater treatment plant was performed in a 10-L reactor. Microbial quality of lime-stabilized sludge was checked for 6 weeks in the reactor. During this stage, pH, FC (fecal coliforms) and viable helminthes ova density were determined and compared with sludge stabilized criteria suggested by USEPA. Results: Average number of fecal coliforms and viable helminthes ova in waste sludge were 1.65 × 10 12 MPN/g of dry solids (DS) and 353 ova/4 g of dry solids, respectively. Conclusions:The results of this study showed that sewage sludge stabilization with hydrated lime reduced fecal coliforms more than 99.99% and also stabilized sludge covered standards of class B of USEPA criteria.

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“…The leaching of Cr and Zn from coal fly ash was responsible for toxic effects of ash/ sewage sludge mixtures toward bacterium Vibrio fischeri (28) and heavy metals leached from oil shale combustion ash showed toxic effect in standardised tests with bacterium, crustacean, and microalgae (18). In general, the leachability from coal fly ash is relatively low and depends on the conditions in the water system.…”

Section: Leaching Of Heavy Metals From Wood Fly Ashmentioning

confidence: 99%

Alkaline disinfection of urban wastewater and landfill leachate by wood fly ash

Ivanković¹,

Hrenović²,

Itskos

et al. 2014

Archives of Industrial Hygiene and Toxicology

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Wood fly ash is an industrial by-product of the combustion of different wood materials and is mostly disposed of as waste on landfills. In our preliminary experiments, wood ash exhibited antibacterial activity against urban wastewater bacteria and we focused on wood fly ash as a potential substrate for wastewater disinfection. The addition of ash at a concentration of 10 g L -1 (1 %) caused an instant increase of pH in urban wastewater and landfill leachate. High pH (10.1-12.7) inactivated bacterial populations in the wastewater and the removal of faecal coliforms and intestinal enterococci after 6 h of contact was 100 % (below the detection limit; <1 CFU per mL) with the most efficient ash sample (ash from combustion of beech) both in urban wastewater and landfill leachate. Properly chosen wood fly ash, i.e. one that tends to increase the pH to the greatest extent, proved to be a very effective disinfection substrate. Considering that water treated with wood ash has a high pH and needs to be neutralised before discharge, ash would be suitable for disinfection of leachates when smaller volumes are treated.

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Investigation of sewage sludge stabilization potential by the addition of fly ash and lime

Cited by 121 publications

References 27 publications

Geotechnics of municipal sludges and residues for landfilling

Geotechnics of municipal sludges and residues for landfilling

Lime Stabilization of Waste Activated Sludge

Alkaline disinfection of urban wastewater and landfill leachate by wood fly ash

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