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Fire Resistance of Sewage Sludge Ash Blended Cement Pastes  [PDF]
M. A. Tantawy,A. M. El-Roudi,Elham M. Abdalla,M. A. Abdelzaher
Journal of Engineering , 2013, DOI: 10.1155/2013/361582
Abstract: The aim of the present study is to investigate the hydration characteristics and the fire resistance of sewage sludge ash blended cement pastes by the determination of compressive strength, bulk density, and total porosity in addition to XRD and SEM techniques. Sewage sludge ash modifies the hydration of cement because of its pozzolanic reaction with portlandite favoring the formation of crosslinked fibrous calcium silicate of low Ca/Si ratio. Hence, it was concluded that thermal damage of cement pastes after the exposure to high treatment temperatures (i.e., crack formation and loss of mechanical properties) was effectively reduced with sewage sludge as content up to 20?wt% because of that the presence of crosslinked fibrous calcium silicate strengthens the cement matrix. 1. Introduction Sewage water is the collection of wastewater effluents from domestic, hospital, commercial, and industrial establishments. The objective of the sewage treatment is to produce treated sewage water and sewage sludge suitable for safe discharge into the environment or reuse [1]. International environmental protection agencies recommended that incineration is an attractive disposal method of sewage sludge [2]. Sewage sludge ash has been used as an additive in the production of construction materials [3], mortars [4], and concrete [5]. The exposure of concrete to high temperatures as in an accidental fire of buildings leads to an undesirable structural quality deterioration [6]. Previous studies illustrate that hardened cement paste plays a key role in high temperatures deterioration process. The main damage mechanisms that discuss the deterioration of concrete at elevated temperatures are thermal mismatch, decomposition of hydrates, coarsening of pore structure, and pore pressure effects [7]. Siliceous aggregates expand around 575°C as a result of the α-β quartz inversion, whereas cement paste shrinks above 200°C [8]. This thermal mismatch (i.e., expansion of siliceous aggregate and shrinkage of cement paste matrix) causes a considerable tension at the aggregate-matrix interface leading eventually to interface fracture and cracking [9]. The decomposition of hydrates occurs during the thermal damage of cementitious materials including the decomposition of ettringite, C-S-H, and carboaluminate hydrates at 180–450°C and portlandite at 425–580°C [10]. The decomposition of portlandite damages the C-S-H. The decomposition of hydrates decreases stiffness and strength of cementitious materials. Volume reduction of the hydrated phases because of the loss of bound water leads to air
Solubility of ion and trace metals from stabilized sewage sludge by fly ash and alkaline mine tailing

ZHANG Hongling,SUN Lina,SUN Tieheng,

环境科学学报(英文版) , 2008,
Abstract: Stabilized sewage sludge (SS) by fly ash (FA) and alkaline mine tailing as artificial soil,to be applied on the ecological rehabilitation at mining junkyards,offers a potentially viable utilization of the industrial by-product,as well as solves the shortage of soil resource in the mine area.An incubation experiment with different ratios of SS and FA was conducted to evaluate the solubility of ions and trace elements from stabilized sewage sludge.Results showed that fly ash offset a decrease in pH value of sewage sludge.The pH of (C) treatment (FA:SS=1:1) was stable and tended to neutrality.The SO42- and Cl- concentrations of the solution in the mixture were significantly decreased in the stabilized sewage sludge by alkaline fly ash and mine tailing,compared to the single SS treatment.Stabilized sewage sludge by FA weakened the nitrification of total nitrogen from SS when the proportion of FA in the mixture was more than 50%.The Cr,Ni,and Cu concentrations in the solution were gradually decreased and achieved a stable level after 22 days,for all treatments over the duration of the incubation.Moreover stabilized sewage sludge by fly ash and/or mine tailing notably decreased the trace metal solubility.The final Cr,Cu,and Ni concentrations in the solution for all mixtures of treatments were lower than 2.5,15,and 50 μg/L,respectively.
The effect of aging on element plant availability and bacterial counts of mixtures of wood ash and sewage sludge
Pousada-Ferradás,Yudani; Seoane-Labandeira,Socorro; Blanco,Miguel; Nú?ez-Delgado,Avelino;
Maderas. Ciencia y tecnología , 2011, DOI: 10.4067/S0718-221X2011000300006
Abstract: this study investigated the chemical composition of a mixture of 70% wood ashes (a by-product of timber-industry) and 30% sewage sludge (% dry weight), immediately after preparation and after storage (42 days). the mixture had higher mehlich 3 extractable ca, mg and k concentrations than either component alone, and low plant-available heavy metal concentrations, both immediately after mixing and after storage for up to 6 weeks. the results support the view that mixtures of this type may be useful for liming and fertilizing, given their neutralizing capacity and phyto nutrient concentrations. furthermore, we compared the survival of escherichia coli in a wood ash and sewage sludge mixture with their survival in mixtures ofsewage sludge and two levels of quicklime. the time needed to eliminate most bacteria was 29 days in the ash-sludge combination, while nine days were required for one of the quicklime-sludge mixtures, and counts were minimal for the quicklime-sludge mixture with a ph>12.
The effect of aging on element plant availability and bacterial counts of mixtures of wood ash and sewage sludge
Yudani Pousada-Ferradás,Socorro Seoane-Labandeira,Miguel Blanco,Avelino Nú?ez-Delgado
MADERAS : Ciencia y Tecnología , 2011,
Abstract: This study investigated the chemical composition of a mixture of 70% wood ashes (a by-product of timber-industry) and 30% sewage sludge (% dry weight), immediately after preparation and after storage (42 days). The mixture had higher Mehlich 3 extractable Ca, Mg and K concentrations than either component alone, and low plant-available heavy metal concentrations, both immediately after mixing and after storage for up to 6 weeks. The results support the view that mixtures of this type may be useful for liming and fertilizing, given their neutralizing capacity and phyto nutrient concentrations. Furthermore, we compared the survival of Escherichia coli in a wood ash and sewage sludge mixture with their survival in mixtures ofsewage sludge and two levels of quicklime. The time needed to eliminate most bacteria was 29 days in the ash-sludge combination, while nine days were required for one of the quicklime-sludge mixtures, and counts were minimal for the quicklime-sludge mixture with a pH>12.
Leaching of phosphorus from incinerated sewage sludge ash by means of acid extraction followed by adsorption on orange waste gel

Biplob Kumar Biswas,Katsutoshi Inoue,Hiroyuki Harada,Keisuke Ohto,Hidetaka Kawakita,

环境科学学报(英文版) , 2009,
Abstract: Ashes from sewage sludge incineration have a high phosphorus content, approximately 8% (W/W), which indicates a potential resource of the limiting nutrient. Incineration of sewage sludge with subsequent recovery of phosphorus is a relatively new sludge treatment technique. In this article, the leaching of phosphorus by using sulfuric acid as well as hydrochloric acid by means of several batch experiments was presented. At the same time a selective recovery of phosphorus by adsorption was also discussed. The e ects of acid concentration, temperature and time on extraction were studied. The phosphorus leaching increased with the increase in acid concentration and temperature. Kinetic studies showed that the complete leaching of phosphorus took place in less than 4 h. Selective adsorption of phosphorus by using orange waste gel provided a hint for recovery of this natural resource, which eventually could meet the ever-increasing requirement for phosphorus. The overall results indicated that the incinerated sewage sludge ash can be treated with acid to e ciently recover phosphorus and thus can be considered a potentially renewable source of phosphorus.
Enzyme activity and microbial biomass in an Oxisol amended with sewage sludge contaminated with nickel
Revoredo, Marcos Donizeti;Melo, Wanderley José de;
Scientia Agricola , 2007, DOI: 10.1590/S0103-90162007000100009
Abstract: the role of nickel in soils of tropical areas under the application of sewage sludge is still not very well known. this study was carried out under greenhouse conditions in jaboticabal, s?o paulo state, brazil, with the objective of evaluating the impact of the application of sewage sludge previously contaminated with rates of nickel (329, 502, 746 and 1119 mg kg-1, dry basis) on a soil cropped with sorghum, in relation to soil enzyme activity and soil microbial biomass. soil samples were collected at the beginning and the end of the experiment. the experimental design was completely randomized, with five treatments (control and four rates of ni in the sewage sludge) and four replications. c and n of the soil microbial biomass and enzyme activities (acid and alkaline phosphatases) were sensitive indicators for impact evaluation caused by sewage sludge contaminated with nickel. there were positive correlations between "total" and extractable nickel (mehlich 1) with c-microbial biomass and negative with the microbial c/n relationship. n-microbial biomass correlated positively with "total" and extractable ni at the last sampling. at the end of the experiment, the acid phosphatase activity correlated negatively with "total" ni while the alkaline phosphatase correlated with both forms of the metal.
Recovery of phosphorus as struvite from sewage sludge ash

Huacheng Xu,Pinjing He,Weimei Gu,Guanzhao Wang,Liming Shao,

环境科学学报(英文版) , 2012,
Abstract: Phosphorus (P) is an element vital for all living organisms, yet the world's reserves of phosphate rock are becoming depleted. This study investigated an effective P recovery method from sludge ash via struvite precipitation. Results showed that more than 95% of the total P content was extracted from sludge ash by applying 0.5 mol/L HCl at a liquid/solid ratio of 50 mL/g. Although heavy metal leaching also occurred during P extraction, cation exchange resin efficiently removed the heavy metals from the P-rich solution. Orthogonal tests showed that the optimal parameters for P precipitation as struvite would be a Mg:N:P molar ratio of 1.6:1.6:1 at pH 10.0. X-ray diffraction analysis validated the formation of struvite. Further investigations revealed that the harvested precipitate had a high struvite content (97%), high P bioavailability (94%), and low heavy metal content, which could be considered a high quality fertilizer.
The experimental study on utilization of the urban sewage sludge in the process of sintering brick with fly-ash and clay
粉煤灰-粘土砖烧制过程处理城市污水污泥的试验研究

REN Bozhi,LONG Tengrui,CHEN Qiunan,
任伯帜
,龙腾锐,陈秋南

环境科学学报 , 2003,
Abstract: Possible utilization of urban sewage sludge, in the process of produetion of sintering brick with fly-ash and was investigatel. The results showed that the burning capacity of coal is raised and improved by adding 20 percent urban sludge containing 80 percent water into the coal. It did not affect the qualities of the sintering end products by adding 30 percent urban sludge contained 80 percent water into the fly-ash and clay. The 50 percent of urban sludge can be consummed in this process.
Principal Physicochemical Properties of Artificial Soil Composed of Sewage Sludge Stabilized by Fly Ash
粉煤灰钝化污泥人工土壤理化性质研究

ZHANG Hong-ling,SUN Li-na,SUN Tie-heng,
张鸿龄
,孙丽娜,孙铁珩

环境科学 , 2008,
Abstract: The pH, nutrients and heavy metals of stabilized sewage sludge were investigated by mixing municipal sewage sludge with alkaline fly ash and mine tailing. The results indicate that water-holding capacity of artificial soil III (FA : SS = 1 : 1) and II (FA : SS = 2 : 1) treatments were significantly higher than that of CK (brown meadow soil), while that of the IV (FA : SS = 1 : 2) treatment was similar to CK; The nutrients contents (organic matter, N, P, K) of stabilized sewage sludge were up to a high fertilizer level. Moreover, with decrease of the ratio of fly ash to sewage sludge, the nutrient content of artificial soils increased. Except total Ni content of III (FA : SS = 1 : 1) treatment was high (187.67 mg x kg(-1)), Cd, Pb, Cu, Zn, and Cr for all artificial soil treatments were all significant lower than control standards for pollutants in sludges and fly ash from Agricultural use (GB 4284-84, GB 8173-87).
Impact of dairy sewage sludge on enzymatic activity and inorganic nitrogen concentrations in the soils
S. Jezierska-Tys,M. Fr?c
International Agrophysics , 2009,
Abstract: Sewage sludge from the treatment wastewater contains nutrients but also contaminants, such as metals, pathogens and organic chemicals. On the contrary, dairy sewage sludges (DSS) usually do not contain these contaminants. We have studied the effect of adding the different doses of DSS (0, 30, 60, 80, 120, 200, 300 and 600 Mg ha-1) on activities dehydrogenase, protease and urease and content of exchangeable NH4+, NO3-, NO2- in a brown soil and a grey-brown podzolic soil in a 240 days experiment. Generally, after the application of DSS enzyme activities initially increased and this increase depended on the dairy sewage sludge added to soil. Afterwards, these values decreased, but generally they remained higher than those of the unamended soils. The decrease in NH4+ concentration coincided with a subsequent increase in the NO3- level. The incorporation of DSS can have a positive effect on the microbial functioning of both grey-brown podzolic and brown soil but the effects should also be verified under field conditions.
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