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

The tropical regions have specific problems associated with high pathogenic density in the sewage sludge. The aim of this study was to select an adequate sludge stabilization and valorization system comparing the performance of four technologies: anaerobic stabilization without heating, aerobic stabilization, alkaline treatment with lime and aerobic composting. The study was performed in a pilot plant which was built and operated during six months. The main problem for the beneficial use of the sludge was its pathogenicity. All the systems allowed obtaining stabilized products which met the bacteriological criteria for some kind of use. The compost and the alkalinized sludge were bacteriologically safe for use without restrictions in accordance with the Mexican regulations. The accomplishment of the parasitological criteria for use was however impossible with the anaerobic and with the aerobic systems. The compost obtained at 55-60°C with 25d aeration time and the alkaline sludge fulfill the criteria established by for forest and agriculture use and for soil conditioning. The composting could reach the requirements for unrestricted use when operated at temperatures 65-70°C during 45 days which makes it the most adequate sludge treatment system for hot climate regions.

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Highly Effective Adsorption Process of Ni(II) Ions with the Use of Sewage Sludge Fly Ash Generated by Circulating Fluidized Bed Combustion (CFBC) Technology

Materials ◽

10.3390/ma14113106 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3106

Author(s):

Tomasz Kalak ◽

Kinga Marciszewicz ◽

Joanna Piepiórka-Stepuk

Keyword(s):

Fly Ash ◽

Sewage Sludge ◽

Fluidized Bed ◽

Circulating Fluidized Bed ◽

Municipal Sewage ◽

Municipal Sewage Sludge ◽

Fluidized Bed Combustion ◽

Nickel Ions ◽

Suitable Material ◽

Circulating Fluidized Bed Combustion

Recently, more and more attention has been paid to the removal of nickel ions due to their negative effects on the environment and human health. In this research, fly ash obtained as a result of incineration of municipal sewage sludge with the use of circulating fluidized bed combustion (CFBC) technology was used to analyze the possibility of removing Ni(II) ions in adsorption processes. The properties of the material were determined using analytical methods, such as SEM-EDS, XRD, BET, BJH, thermogravimetry, zeta potential, SEM, and FT-IR. Several factors were analyzed, such as adsorbent dose, initial pH, initial concentration, and contact time. As a result of the conducted research, the maximum sorption efficiency was obtained at the level of 99.9%. The kinetics analysis and isotherms showed that the pseudo-second order equation model and the Freundlich isotherm model best suited this process. In conclusion, sewage sludge fly ash may be a suitable material for the effective removal of nickel from wastewater and the improvement of water quality. This research is in line with current trends in the concepts of circular economy and sustainable development.

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Dried Municiple Sewage Sludge Gasification Experiment in Dual Fluidized Bed

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.383-390.3799 ◽

2011 ◽

Vol 383-390 ◽

pp. 3799-3804

Author(s):

Xiao Xu Fan ◽

Lei Zhe Chu ◽

Li Guo Yang

Keyword(s):

Fly Ash ◽

Sewage Sludge ◽

Fluidized Bed ◽

Calorific Value ◽

Municipal Sewage ◽

Municipal Sewage Sludge ◽

Test Results ◽

Leaching Toxicity ◽

Dual Fluidized Bed ◽

Hot Test

The fuel characteristics of municipal sewage sludge are suitable for dual fluidized bed(DFB) gasification, which can get middle calorific value gas through volatile pyrolysis, and reduce volume through char combustion. The hot test results of municipal sewage sludge on DFB rig were showen that the temperature distribution along combustor heigh is uniform, and the carbon content of fly ash is about 2~3%. In the experiment, with the increase of gasifier temperatrue, the more volatile of the sewage sludge was pyrolyzed. When the temperature of the gasifier reached 800°C, the calorific value of gas was 6.9MJ/Nm3; the emissions of SO2, NOx and HCl were appropriate to the standard. The leaching toxicity of heavy metal of the fly ash was lower than the discharge standard.

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Biolixiviation des métaux lourds et stabilisation des boues d'épuration : essai en bioréacteur opéré en mode cuvée

Canadian Journal of Civil Engineering ◽

10.1139/l93-006 ◽

1993 ◽

Vol 20 (1) ◽

pp. 57-64 ◽

Cited By ~ 12

Author(s):

R. D. Tyagi ◽

J. F. Blais ◽

N. Meunier ◽

D. Kluepfel

Keyword(s):

Heavy Metals ◽

Sewage Sludge ◽

Suspended Solids ◽

Elemental Sulfur ◽

Batch Reactor ◽

Fecal Coliforms ◽

Sludge Stabilization ◽

Sludge Digestion ◽

Batch Time ◽

Phosphorus And Potassium

A biological process of heavy metals solubilization and sewage sludge stabilization was studied in a batch reactor of 30-L capacity. The acclimatized leaching microflora was composed of two major groups of thiobacilli: less acidophilic and acidophilic. A batch time of 10 days allows a substantial metal solubilization: cadmium (100%), copper (80%), manganese (80%), nickel (46%), and zinc (100%). The bioleaching process also causes a significative decrease in sludge total suspended solids (25%) and volatile suspended solids (32%), and a considerable reduction (under the detection limit of 10 cfu∙mL−1) of indicator bacteria (total coliforms, fecal coliforms, fecal streptococci). After filtration or centrifugation of the leached sludge, the solubilized metals were precipitated by lime neutralization. The phosphorus and potassium sludge contents were not affected by bioleaching process. These results indicate that the process of sludge digestion and metal leaching can be conducted in parallel in the same reactor. Key words: sewage sludge, heavy metals, bioleaching, stabilization, thiobacilli, elemental sulfur.

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