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SEM Images of MS7 modified dredged sludge sample. (a) 0~2 cm sample, (b) 4~6 cm sample, (c) 8~10 cm sample.
Source publication
In order to prepare a new type of landfill covering material for closure, we used industrial calcium-containing waste (construction rubbish, slag, desulfurized gypsum and fly ash) to modify the dredged urban sludge. Shrink, unconfined compression, shear and infiltration tests were performed to obtain the volume shrinkage, compressive strength, shea...
Contexts in source publication
Context 1
... surface micro-morphology of the modified sludge sample is shown in Figure 9. Figure 9a-c shows that there are cluster-like structural substances on the surface of the sample, and the cluster-like substances are closely connected with soil particles. ...
Context 2
... surface micro-morphology of the modified sludge sample is shown in Figure 9. Figure 9a-c shows that there are cluster-like structural substances on the surface of the sample, and the cluster-like substances are closely connected with soil particles. The clusterlike substances in Figure 9c are significantly more than those in Figure 9a. ...
Context 3
... surface micro-morphology of the modified sludge sample is shown in Figure 9. Figure 9a-c shows that there are cluster-like structural substances on the surface of the sample, and the cluster-like substances are closely connected with soil particles. The clusterlike substances in Figure 9c are significantly more than those in Figure 9a. In addition, many pores appeared on the surface of the sample in Figure 9a, but the pores obviously decreased in Figure 9c, and the original pores were filled by cluster-like substances. ...
Context 4
... surface micro-morphology of the modified sludge sample is shown in Figure 9. Figure 9a-c shows that there are cluster-like structural substances on the surface of the sample, and the cluster-like substances are closely connected with soil particles. The clusterlike substances in Figure 9c are significantly more than those in Figure 9a. In addition, many pores appeared on the surface of the sample in Figure 9a, but the pores obviously decreased in Figure 9c, and the original pores were filled by cluster-like substances. ...
Context 5
... clusterlike substances in Figure 9c are significantly more than those in Figure 9a. In addition, many pores appeared on the surface of the sample in Figure 9a, but the pores obviously decreased in Figure 9c, and the original pores were filled by cluster-like substances. This may be due to the fact that the calcium-containing solid waste generates hydration products, C-S-H and C-A-S-H hydration gels, under the action of alkali activation, to fill the pores between soil particles, thus forming a structure with firm skeleton characteristics between soil particles and gels, which is an important reason for the high mechanical strength of modified sludge. ...
Context 6
... clusterlike substances in Figure 9c are significantly more than those in Figure 9a. In addition, many pores appeared on the surface of the sample in Figure 9a, but the pores obviously decreased in Figure 9c, and the original pores were filled by cluster-like substances. This may be due to the fact that the calcium-containing solid waste generates hydration products, C-S-H and C-A-S-H hydration gels, under the action of alkali activation, to fill the pores between soil particles, thus forming a structure with firm skeleton characteristics between soil particles and gels, which is an important reason for the high mechanical strength of modified sludge. ...
Context 7
... surface micro-morphology of the modified sludge sample is shown in Figure 9. Figure 9a-c shows that there are cluster-like structural substances on the surface of the sample, and the cluster-like substances are closely connected with soil particles. ...
Context 8
... surface micro-morphology of the modified sludge sample is shown in Figure 9. Figure 9a-c shows that there are cluster-like structural substances on the surface of the sample, and the cluster-like substances are closely connected with soil particles. The cluster-like substances in Figure 9c are significantly more than those in Figure 9a. ...
Context 9
... surface micro-morphology of the modified sludge sample is shown in Figure 9. Figure 9a-c shows that there are cluster-like structural substances on the surface of the sample, and the cluster-like substances are closely connected with soil particles. The cluster-like substances in Figure 9c are significantly more than those in Figure 9a. In addition, many pores appeared on the surface of the sample in Figure 9a, but the pores obviously decreased in Figure 9c, and the original pores were filled by cluster-like substances. ...
Context 10
... surface micro-morphology of the modified sludge sample is shown in Figure 9. Figure 9a-c shows that there are cluster-like structural substances on the surface of the sample, and the cluster-like substances are closely connected with soil particles. The cluster-like substances in Figure 9c are significantly more than those in Figure 9a. In addition, many pores appeared on the surface of the sample in Figure 9a, but the pores obviously decreased in Figure 9c, and the original pores were filled by cluster-like substances. ...
Context 11
... cluster-like substances in Figure 9c are significantly more than those in Figure 9a. In addition, many pores appeared on the surface of the sample in Figure 9a, but the pores obviously decreased in Figure 9c, and the original pores were filled by cluster-like substances. This may be due to the fact that the calcium-containing solid waste generates hydration products, C-S-H and C-A-S-H hydration gels, under the action of alkali activation, to fill the pores between soil particles, thus forming a structure with firm skeleton characteristics between soil particles and gels, which is an important reason for the high mechanical strength of modified sludge. ...
Context 12
... cluster-like substances in Figure 9c are significantly more than those in Figure 9a. In addition, many pores appeared on the surface of the sample in Figure 9a, but the pores obviously decreased in Figure 9c, and the original pores were filled by cluster-like substances. This may be due to the fact that the calcium-containing solid waste generates hydration products, C-S-H and C-A-S-H hydration gels, under the action of alkali activation, to fill the pores between soil particles, thus forming a structure with firm skeleton characteristics between soil particles and gels, which is an important reason for the high mechanical strength of modified sludge. ...
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Citations
... With most studies focusing on the hydraulic conductivity and strength properties of the materials [21,22], there is scarce data available on the environmental impact, such as the leaching of hazardous chemicals from the mixtures. A six-month study conducted by the authors of [23] has demonstrated that the hydraulic conductivity of the SS:RG composite can be maintained at 10 −6 cm/s and the leaching of chemicals from the composite is within the regulated limits when flowing distilled water through the composite. ...
This paper examines the environmental impact of the use of compacted sewage sludge: red gypsum (SS:RG) mixture as intermediate landfill cover in terms of yield and quality of leachate as characterised by hydraulic conductivity and leaching behaviour. A series of column tests using the constant head method is carried out by percolating the synthetic leachate through samples that have been compacted at various degrees (60, 70, 75, 80 and 85%). The leachate quality is monitored at
pre-determined days for pH, COD, Cu, Fe and Zn. In general, hydraulic conductivity decreases in three stages, in which the first stage is mainly attributed to the particle rearrangement and hydration of calcium silicate hydrate (CSH). The hydration of CSH increases the pH, which causes the heavy metal to precipitate and be entrapped within the matrices of CSH gel, thereby further reducing the porosity and hydraulic conductivity. A minimum of 75% compaction has shown favourable final
porosity, hydraulic conductivity, and leachate quality, although a minimum of 80% compaction is recommended in order to achieve a satisfactory compressive strength of greater than 345 kPa for a landfill operation.
... Other studies have depicted the significant evolution of MWW, MSS management, and environmental remediation in China [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57]. ...
Municipal sewage sludge is the residual material produced as a waste of municipal wastewater purification. It is a sophisticated multi-component material, hard to handle. For many years, it has been landfilled, incinerated, and widely used in agriculture practice. When unproperly discharged, it is very polluting and unhealthy. The rapidly increasing global amount of municipal sewage sludge produced annually depends on urbanization, degree of development, and lifestyle. Some diffused traditional practices were banned or became economically unfeasible or unacceptable by the communities. In contrast, it has been established that MSS contains valuable resources, which can be utilized as energy and fertilizer. The objective of the review was to prove that resource recovery is beneficially affordable using modern approaches and proper technologies and to estimate the required resources and time. The open sources of information were deeply mined, critically examined, and selected to derive the necessary information regarding each network segment, from the source to the final point, where the municipal sewage sludge is produced and disposed of. We found that developed and some developing countries are involved with ambitious and costly plans for remediation, the modernization of regulations, collecting and purification systems, and beneficial waste management using a modern approach. We also found that the activated sludge process is the leading technology for wastewater purification, and anaerobic digestion is the leading technology for downstream waste. However, biological technologies appear inadequate and hydrothermal carbonization, already applicable at full scale, is the best candidate for playing a significant role in managing municipal sewage sludge produced by big towns and small villages.
