scholarly journals Geotechnical properties of sewage sludge solidified with Sulphoaluminate cement

2019 ◽  
Vol 81 ◽  
pp. 01015 ◽  
Author(s):  
Xihui Fan ◽  
Haoqing Xu ◽  
Shengwei Wang ◽  
Shi Shu ◽  
Naixi Lin ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Construction Material ◽  
High Water ◽  
Organic Soil ◽  
Geotechnical Properties ◽  
High Water Content ◽  
Atterberg Limit ◽  
Sulphoaluminate Cement ◽  
The Impact ◽  
Landfill Disposal

The geotechnical properties of sewage sludge solidified with sulphoaluminate cement are presented. The sludge has a high water content and organic matter which is not easy to disposal. After Solidification/Stabilization (S/S), landfill disposal of sewage sludge is widely adopted in China. However, there is little research focused on the geotechnical properties of sewage sludge after S/S treatment and the impact on the landfill site is also difficult to be evaluated. To solve this problem, this paper is aimed to evaluate the basic mechanics properties of solidified materials by means of Atterberg limit, triaxial test, consolidation test and permeability test. The result showed that the strength and the hydraulic conductivity of the modified sludge was close to that of the high organic soil. By adding suitable additives, modified sludge could not only satisfy the requirement of being landfilled but also be utilized as a construction material.

scholarly journals Elementary analysis and energetic potential of the municipal sewage sludges from the Gdańsk and Kościerzyna WWTPs

2018 ◽  
Vol 26 ◽  
pp. 00004
Author(s):  
Arkadiusz Ostojski
Keyword(s):  
Sewage Sludge ◽  
Water Content ◽  
Calorific Value ◽  
High Water ◽  
Municipal Sewage ◽  
Municipal Sewage Sludge ◽  
High Water Content ◽  
Sewage Sludges ◽  
Heating Value ◽  
Elementary Analysis

This paper aims to present municipal sewage sludge (MSS) elementary analysis and energetic potential based on measurement of heat of combustion (higher heating value HHV) and calculation of calorific values (lower heating value LHV). The analysis takes into the consideration water content in sewage sludge, at different utilization stages, in wastewater treatment plants in Gdańsk Wschód and Kościerzyna – Pomeranian Voivodeship. The study yielded the following results (in % dry matter): ash 19÷31 %, C - 31÷36 %, H - 5÷6 %, N - 4÷6 %, O - 28÷32 %, S – 1 %. Calorific value of stabilized sludges in Gdańsk was on average 13.8÷15 MJ/kg. In case of sludges not undergoing digestion from Kościerzyna WWTP, the calorific value was at the level of 17.5 MJ/kg. Thus, sewage sludges are good energy carriers. High water content though is the problem, as it lowers the useful effect of heat. There is no alternative for thermal sewage sludge neutralization, which is in conformity with valid Polish National Waste Management Plan (KPGO 2022).

Parameter investigation for decentralised dewatering and solar thermic drying of sludge

2005 ◽  
Vol 51 (10) ◽  
pp. 65-73 ◽  
Author(s):  
B. Wett ◽  
M. Demattio ◽  
W. Becker
Keyword(s):  
Sewage Sludge ◽  
Initial Conditions ◽  
Simulated Data ◽  
Field Tests ◽  
High Water ◽  
High Water Content ◽  
Secondary Importance ◽  
Initial Height ◽  
Sludge Cake ◽  
Slurry Layer

The purpose of this paper is an experimental and model assisted investigation of the capabilities of a dewatering system for sewage sludge for decentralised sites. Laboratory and field tests are performed with different initial conditions and the influences of filter medium, initial height, initial total suspended solids, temperature and relative humidity are discussed. The experimental work shows the feasibility of geotextile media for dewatering high water content sewage sludge and that the textile structure is of secondary importance. The specific filter resistance of the sludge cake is found to be the most significant factor in dewatering applications. The mathematical description of the dewatering process is based on the superposition of two models, the Conventional Filtration Theory for the filtration phase and the BT-model for the drying phase. Feasibility and limits of the theoretical approach are evaluated by means of a comparison between measurements and simulated data of cyclic reloading tests. It is found that a better filtration efficiency is achieved at higher TSS and at lower initial height of the slurry layer. Due to the viscosity decrease, a higher temperature enhances not only evaporation, but also filtration rate.

scholarly journals Peat soil mass stabilization using geopolymeric hybrid material in early age

2019 ◽  
Vol 276 ◽  
pp. 05003
Author(s):  
Gunawan Wibisono ◽  
Erwin ◽  
Alfian Kamaldi ◽  
Monita Olivia
Keyword(s):  
Fly Ash ◽  
Cement Hydration ◽  
Peat Soil ◽  
High Water ◽  
Organic Soil ◽  
Soil Mass ◽  
High Water Content ◽  
Strength Development ◽  
Initial Strength ◽  
Pozzolanic Material

Peat is an organic soil, highly compressible and has high water content. The soil needs to be stabilized chemically by incorporating binders such as cement and lime into the soil that will change the properties and soil strength. However, stabilization using cement solely is not recommended since the organic acid in peat soil could delay cement hydration process. Furthermore, mass stabilization using pozzolanic material also could improve strength development of peat soil. In this research, the pozzolanic material in the form of geopolymer hybrid or geopolymer with the addition of Ordinary Portland Cement was investigated. Geopolymer was produced by activating fly ash with a combination of NaOH and sodium silicate. OPC addition improves initial strength and assists geopolymerization at ambient temperature. Variables studied were binder content and a percentage of OPC, and percentage of fly ash. Unconfined Compressive Stress (UCS) at 7 days was measured for all specimens. Mass stabilization using fly ash geopolymer hybrid could improve strength development of peat soil.

scholarly journals Designing robust chitosan-based hydrogels for stem cell nesting under oxidative stress

Bioimpacts ◽  
2021 ◽  
Author(s):  
Zahra Olfat Noubari ◽  
Asal Golchin ◽  
Marziyeh Fathi ◽  
Ailar Nakhlband
Keyword(s):  
Oxidative Stress ◽  
Tissue Engineering ◽  
Stem Cells ◽  
Porous Structure ◽  
High Water ◽  
High Water Content ◽  
Dapi Staining ◽  
Antioxidant Genes ◽  
Wide Range ◽  
The Impact

Introduction: Hydrogels are unique candidates for a wide range of biomedical applications including drug delivery and tissue engineering. The present investigation was designed to consider the impact of chitosan-based hydrogels as a scaffold on the proliferation of human bone marrow mesenchymal stem cells (hBM-MSCs) besides neutralization of oxidative stress in hBM-MSCs. Methods: Chitosan (CS) and CS-gelatin hydrogels were fabricated through ionic crosslinking using β-glycerophosphate. The hBM-MSCs were cultured on the prepared matrices and their proliferation was evaluated using DAPI staining and MTT assay. Furthermore, the effect of hydrogels on oxidative stress was assessed by measuring the expression of NQO1, Nrf2, and HO-1 genes using real-time PCR. Results: The developed hydrogels indicated a porous structure with high water content. The toxicity studies showed that the prepared hydrogels have a high biocompatibility/cytocompatibility. The expression of intracellular antioxidant genes was studied to ensure that stress is not imposed by the scaffold on the nested cells. The results showed that Nrf2 as a super transcription factor of antioxidant genes and its downstream antioxidant gene, NQO1 were downregulated. Unexpectedly, the upregulation of HO-1 was detected in the current study. Conclusion: The prepared CS-based hydrogels with desired properties including porous structure, high swelling ability, and cytocompatibility did not show oxidative stress for the nesting of stem cells. Therefore, they could be attractive scaffolds to support stem cells for successful tissue engineering purposes.

High water content material based on ba-bearing sulphoaluminate cement

2005 ◽  
Vol 20 (3) ◽  
pp. 88-90 ◽  
Author(s):  
Chang Jun ◽  
Cheng Xin ◽  
Lu Lingchao ◽  
Huang Shifeng ◽  
Ye Zhengmao
Keyword(s):  
Water Content ◽  
High Water ◽  
High Water Content ◽  
Sulphoaluminate Cement

scholarly journals Impact of Number of Segmented Tissues on SAR Prediction Accuracy in Deep Pelvic Hyperthermia Treatment Planning

Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2646
Author(s):  
Iva VilasBoas-Ribeiro ◽  
Gerard C. van Rhoon ◽  
Tomas Drizdal ◽  
Martine Franckena ◽  
Margarethus M. Paulides
Keyword(s):  
Treatment Planning ◽  
High Water ◽  
Specific Model ◽  
Treatment Quality ◽  
Patient Specific ◽  
High Water Content ◽  
Treatment Optimization ◽  
Hyperthermia Treatment ◽  
Pre Treatment ◽  
The Impact

In hyperthermia, the general opinion is that pre-treatment optimization of treatment settings requires a patient-specific model. For deep pelvic hyperthermia treatment planning (HTP), tissue models comprising four tissue categories are currently discriminated. For head and neck HTP, we found that more tissues are required for increasing accuracy. In this work, we evaluated the impact of the number of segmented tissues on the predicted specific absorption rate (SAR) for the pelvic region. Highly detailed anatomical models of five healthy volunteers were selected from a virtual database. For each model, seven lists with varying levels of segmentation detail were defined and used as an input for a modeling study. SAR changes were quantified using the change in target-to-hotspot-quotient and maximum SAR relative differences, with respect to the most detailed patient model. The main finding of this study was that the inclusion of high water content tissues in the segmentation may result in a clinically relevant impact on the SAR distribution and on the predicted hyperthermia treatment quality when considering our pre-established thresholds. In general, our results underline the current clinical segmentation protocol and help to prioritize any improvements.

scholarly journals Changes in toxic elements content of soil after sewage sludge treatment in energy willow plantation

2012 ◽  
pp. 7-10
Author(s):  
Tibor József Aranyos ◽  
Marianna Makádi ◽  
Attila Tomócsik
Keyword(s):  
Sewage Sludge ◽  
Toxic Elements ◽  
Treatment Plant ◽  
Energy Resource ◽  
High Water ◽  
Toxic Element ◽  
High Water Content ◽  
Excess Sludge ◽  
Sludge Treatment ◽  
Total N

The primary purpose of our experiment was the solution of municipal excess sludge treatment by a renewable energy resource used willow (Salix viminalis L.) plantation. Tests were carried out to state whether the applied sewage sludge has caused any accumulation of the toxic elements in the studied soil layers, and - based on the results –to see whether the plantation is suitable for the treatment of municipal sewage sludge.The excess sludge (sludge before dewatering) is beneficial for the willow, because it contains a 3–5% dry matter and therefore, a lot of water, too. This high water content ensures the high water amount needed for the intensive growth of the willow. On the other hand, the wastewater treatment plant can save the dewatering cost which corresponds to about 30% of the water treatment process costs. The amounts of the sprinkled sewage sludge were calculated on the basis of its total nitrogen content. Treatments were the followings: control, 170 N kg ha-1 year-1 and 250 N kg ha-1 year-1. The mean values of the toxic element concentrations in the sewage sludge did not cross the permitted limits of the land  accommodating. The measured toxic element values of the soil were compared to the limits of the 50/2001. (IV.3.) Government Regulation.The  sprinkled sewage sludge on the bases of the total N content did not cause accumulation of heavy metals in the soil and the treated plants were also healthy without any signs of toxicity. 

Laboratory test study on the effect of freeze–thaw cycles on strength and hydraulic conductivity of high water content stabilized dredged sediments

2016 ◽  
Vol 53 (6) ◽  
pp. 1038-1045 ◽  
Author(s):  
Gregory Makusa ◽  
Josef Mácsik ◽  
Göran Holm ◽  
Sven Knutsson
Keyword(s):  
Hydraulic Conductivity ◽  
High Water ◽  
High Water Content ◽  
Initial Water ◽  
Dredged Sediments ◽  
Freeze Thaw ◽  
Test Study ◽  
Thaw Consolidation ◽  
Permanent Loss ◽  
The Impact

Dredged sediments with initial water contents between 200% and 400% were treated with single and composite binders. Samples were subjected to open and semi-closed freeze–thaw (f–t) cycles to investigate the impact of f–t cycling on hydraulic conductivity (HC) and unconfined compressive strength (UCS). A grace period (GP) for thaw consolidation is included to assess healing potential of the affected stabilized mass. Findings of this study show that the impact of f–t cycles depends on initially achieved UCS and HC values prior to the f–t cycling and time of testing after f–t cycles. The HC of specimens with an initial UCS value of 87 kPa increased with number of f–t cycles. The UCS values decreased in the range of 50%–80% when specimens were tested directly after the thaw period and values decreased in the range of 14%–60% when specimens were tested at the end of the GP. The HC of specimens with an initial UCS value of 299 kPa remained almost the same. These samples experienced permanent loss in the UCS values, irrespective of time of testing. Detrimental effects of the freezing action on the UCS were greater under semi-closed than open freezing conditions.

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