The fundamentals of lime treatment for dewatered sludge and main factors which affect the treatment process are introduced in this study. According to the results, higher effective calcium oxide content in lime contributes to faster heating rate of the semi-dry system and better effects of semi-dry process. Sludge at the moisture content of 45%-55% after the semi-dry process can be well balled while that at the moisture content of 35% can easily get collapsed and has hard surface. Mechanical design parameters are determined by experiments. The optimum stirring time is 5-10mins when well stirred and the stirring rate should be slow. Heat preservation jacket is needed for the machine and the water vapor, which is produced by heating, should be exhausted in time.
Abstract-Sludge samples are taken from Qige Waste Water Treatment Plant in Hangzhou. The drying characteristics of sludge are determined by self-made small batch type drying machine. The paddle dryer and disc dryer are used in the drying tests to explore the effect of blade form on the sludge drying viscosity zone. Different heat source temperature and drying machine speed are set up for the same kind of drying machine to research on the effect of working conditions on the drying characteristics of sewage sludge. It is discovered that the paddle dryer has a better ability to overcome the sludge viscosity zone. High speed and drying temperature can speed up the sludge drying and improve the dry deterioration in the sludge viscosity zone. But it is necessary to consider the factors of equipment stability and safe operation at the same time.
Abstract-With modulus (KH = 0.89, SM = 2.42, IM = 1.70), substituting the sludge for the shale in the calculation of the cement burden, we studied the influence of different amount of sludge on the cement raw meal sintering, mineral composition, compression strength and the leaching value of heavy metal element. The result indicates that as the proportion of the sludge increased, the free calcium oxide reduced first and increased later, while the compression strength increased first and then reduced. When the proportion of the sludge was 2.56%, the amount of the free calcium oxide in clinker was lowest, and the 28day-compression strength reached the maximum which was 1.37 times as large as the cement clinker without sludge. The XRD and SEM test results also show that the composition of clinker and mineral structure remains unchanged when shale replaced by sludge. When the sludge proportion is 12.18%, free calcium oxide and compression strength are nearly the same as the cement clinker without sludge, and leaching value of heavy metals could satisfy the concentration limits of hazard constituent in the lixivium
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.