Atomized sludges via spray-drying at low temperatures: An alternative to conventional wastewater treatment plants

Abstract

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. b s t r a c tRemoval of sludges from Wastewater Treatment Plants (WWTP) represents a serious worldwide environmental problem for which alternatives other than their simple incineration are investigated. In this work the treatment of raw sludge from urban WWTP by means of a minimization process through spraydrying is analyzed as well as some proposals for revaluating the resulting dry product. Analysis is supported by some experimental results obtained with a laboratory spray dryer. The experimental procedure at laboratory scale is extrapolated to an industrial plant scale. An economic analysis of the proposal in relation to other possible sludge treatments is presented, taking into account in this case the comparison between the costs of the processes of sludge thickening, stabilization and dehydratation and the costs of spray-drying (especially power consumption), minimization of the final waste and reuse options. Finally, an environmental balance of the process is presented. In contrast with the classical treatment line, this alternative allows transforming sludges, i.e., a waste, into a valuable product with several applications.

Modeling of Seepage Losses in Sewage Sludge Drying Bed

“…[18]. The main problem in treating urban wastewaters is basically reduced to finding an environmentally correct technology at the lowest cost [19]. , to enable determine the initial water content of the sludge.…”

“…Case (19) Different values of a were substituted in the Equation (19) by trial and error to generate different sets of data which were regressed on time t , and the set which gave the highest value of coefficient of correlation ' 'r was taken as the value of ' a '. Table 5 is a typical example of trial and error exercise when…”

Drying and characterization of evaporator concentrates coming from PWR

“…Many industries, such as food, pharmaceutical, and agriculture, use this process because it is efficient for the volume reduction [18]. There are R&D studies of drying processes for liquid sewage waste, as well as evaporator concentrate [19]. In Germany, the FAVORITE® process includes the vacuum drying of evaporator concentrates, resins, among others [20].…”

“…The parameters of this equipment are entrance and exit temperature, rotation speed, and workflow. The final product of this process is a solid material with an aspect of a powder [18,24].…”