Experimental study on treating landfill sludge by preconditioning combined with vacuum preloading: Effects of freeze-thaw and FeCl3 preconditioning

Wu, Yajun; Xu, Yang; Zhang, Xudong; Lu, Yitian; He, Xinyan; Song, Binjie; Zhang, Yunda; Ji, Jiawei

doi:10.1016/j.scitotenv.2020.141092

Cited by 49 publications

(19 citation statements)

References 38 publications

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“…e settlement stabilization process of postclosure landfills is significant for the effective operation of transportation facilities (such as road and bridge), which were built above these landfills. Acceleration of the waste mineralization process can effectively reduce postsettlement and differential settlement of landfills, which would avoid the failure of the above transportation facilities [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Leachate Recirculation Effect on the Acceleration of Waste Mineralization Process by Using a Coupled Numerical Model

Liu

Huyan

Cui

et al. 2021

Advances in Civil Engineering

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Accelerating the waste mineralization is of great significance to control the settlement of transportation facilities nearby landfills. Mineralized waste can also be used as road construction materials to recycle waste resources and reduce the construction cost of transportation facilities. A biochem-hydro-mechanical-solute migration-coupled model for describing complex interactions in landfills with high kitchen waste content has been developed. The proposed model can consider large leachate production and landfill gas entrapment due to the fast degradation of kitchen waste. The quantitative effects of three leachate recirculation conditions are investigated in this article via a typical landfill cell. According to the simulation results, introducing methanogen into landfills with leachate recirculation can relieve acidification caused by fast hydrolysis of kitchen waste and speed up the mineralization process of landfills with high kitchen waste content significantly. Furthermore, landfill gas generation potential loss and fast degradation compression should be considered in the implementation of leachate recirculation in landfills with high kitchen waste content, which helps to maintain the operation of transportation facilities nearby landfills and improve the economic and environmental benefits of leachate treatment.

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Section: Introductionmentioning

confidence: 99%

Evaluation of Leachate Recirculation Effect on the Acceleration of Waste Mineralization Process by Using a Coupled Numerical Model

Liu

Huyan

Cui

et al. 2021

Advances in Civil Engineering

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“…But when cake is formed on the filter paper, the liquid saturation would first decrease and then approach a constant value which was less than unity. Arend et al [7] investigated fluid flow through a porous media experimentally and theoretically and concluded that capillary suction time would increase when cake is formed in the CSA [8,9]. Though cylindrical capillary suction apparatus (CCSA) is very easy to use, there are several shortcomings.…”

Section: Introductionmentioning

confidence: 99%

Factors Affecting Capillary Suction Time of Sludge Using Wet Front Distance and Filtrate Flow Rate Methods

Onoh

Ademiluyi

Amah

2021

AJARR

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Sludge generated during wastewater treatment is difficult to handle due to their high water content, hence a need for dewatering. The factors that affect the outcome of capillary suction time (CST) were studied using piggery and domestic sludge samples conditioned with ferric chloride. Effects of conditioner concentration, hydrostatic pressure and mixing time were investigated. Filtrate flow rate studies were also carried out as an alternative to wet front progression to determine CST. Ferric chloride was varied from 0.002 to 0.008 g/ml, hydrostatic height was varied from 20 to 40 mm while mixing time ranged from 0 to 120 sec. The optimum conditioner concentration was observed to be 0.0055 and 0.0035 g/ml for piggery sludge and domestic sludge respectively. At 5 % level of significance, hydrostatic height was observed to have no significant effect on the CST for the range of hydrostatic heights chosen. The optimum mixing time observed for 90 g/l and 30 g/l piggery sludge was 50 and 25 sec respectively. While the optimum mixing time for 28 g/l and 14 g/l domestic sludge was 10 and 5 sec respectively. Flow rate was discovered to have an inverse relationship with CST, with the optimum conditioner concentration corresponding to the peak flow rate and minimum CST for both test samples. Hence, in other to eliminate the difficulty presented by the anisotropic property of the capillary suction apparatus (CSA) filter paper, filtrate flow method can be used instead of wet front progression method.

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“…The primary reason for dehydration is the formation of ice crystals during freezing (Halde 1980;Mowla et al 2013;Tuan and Sillanpää 2010). In general, the freezing temperature is the primary factor affecting the e ciency of sludge F/T dehydration, whereas the thawing conditions have little effect on the sludge dehydration performance (Wu et al 2020b). According to the research of Vesilind et al (Vesilind and Martel 1990), slow freezing rate can result in good dewatering performance of the sludge during freezing, and slow freezing rate is determined by high freezing temperature.…”

Section: Introductionmentioning

confidence: 99%

Freeze–thaw combined with activated carbon improves electrochemical dewaterability of sludge: Analysis of sludge floc structure and dewatering mechanism

Huang

Song

Yin

et al. 2021

Preprint

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Freeze–thaw (F/T) and electrochemistry are environment-friendly and efficient sludge treatment technologies. In this study, F/T and electrochemistry were combined in the pretreatment of sludge dewatering in the laboratory, and activated carbon (AC) was added to improve the electrochemical dewatering performance of sludge. During the experiment, the effect of F/T on the floc structure was analyzed by a laser particle analyzer and scanning electron microscope. F/T treatment not only improved the dewatering performance of sludge, but also promoted the aggregation of sludge flocs into larger particles. The median diameter (D50) increased from 45.27 µm to 128.94 µm. Then, the intracellular polymer of large-particle sludge was analyzed by three-dimensional excitation–emission matrix (3D-EEM). The tightly bound extracellular polymeric substances (TB-EPS) still contained a large amount of protein substances, which hindered the improvement of sludge dewatering performance. AC was added to the thawed sludge solution before electrochemical treatment (EP). The conductivity of AC enhanced the effect of EP, thereby cracking the sludge flocs. Thus, the light intensity of TB-EPS in the 3D-EEM fluorescence spectroscopy was decreased, and the D50 was also reduced to 105.3 µm. The final specific resistance of filtration and water content were reduced by 96.39% and 32.17%, respectively. Element analysis of the sludge cake after dehydration showed that the addition of AC significantly improved the combustion efficiency of the sludge cake. Moreover, preliminary economic analysis showed that the cost of this research was low, which indicated the potential application value of combined treatment.

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Experimental study on treating landfill sludge by preconditioning combined with vacuum preloading: Effects of freeze-thaw and FeCl3 preconditioning

Cited by 49 publications

References 38 publications

Evaluation of Leachate Recirculation Effect on the Acceleration of Waste Mineralization Process by Using a Coupled Numerical Model

Evaluation of Leachate Recirculation Effect on the Acceleration of Waste Mineralization Process by Using a Coupled Numerical Model

Factors Affecting Capillary Suction Time of Sludge Using Wet Front Distance and Filtrate Flow Rate Methods

Freeze–thaw combined with activated carbon improves electrochemical dewaterability of sludge: Analysis of sludge floc structure and dewatering mechanism

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