Print Email Facebook Twitter The role of growth media on composition, bioconversion and susceptibility for mild thermal pre-treatment of waste activated sludge Title The role of growth media on composition, bioconversion and susceptibility for mild thermal pre-treatment of waste activated sludge Author Gonzales, A. (TU Delft Sanitary Engineering) van Lier, J.B. (TU Delft Sanitary Engineering) de Kreuk, M.K. (TU Delft Sanitary Engineering) Date 2021 Abstract The highly variable characteristics of waste activated sludge (WAS) hinder the comparison of experimental results on WAS bioconversion between the different studies that use excess sludge from different origin. Sludge grown under laboratory conditions with synthetic wastewater as feed showed high resistance to commonly applied pre-treatment techniques, such as thermal pre-treatment. However, a distinctly higher bioconversion of this sludge was recorded compared to WAS from a full-scale wastewater treatment plant (WWTP). The observed results casted concern on the suitability of the experimental laboratory-based data for practice. The physicochemical and biochemical characteristics of both WAS and lab-grown sludge are dependent on the wastewater characteristics or growth media on which the sludges were grown. The objective of this study was to formulate a growth medium that results into a lab-grown sludge which shows high similarity to the WAS coming from a specific full-scale WWTP in response to a pre-treatment technique. More specifically, in this study we targeted the formation of slowly-biodegradable lab-grown sludge that is similarly responsive to mild thermal pre-treatment with H2O2 addition. By comparing real and synthetic wastewaters, we discussed the various wastewater constituents that may lead to a higher degree of recalcitrance of the produced sludge. We then formulated a growth medium, which was fed to a lab-scale activated sludge reactor and evaluated the nutrient removal capacity, as well as the characteristics of the cultivated sludge before and after pre-treatment. Finally, the growth medium was modified to provoke a change in both the bioconversion and in the response to mild thermal pre-treatment. The growth medium proposed in this study resulted in a slowly-biodegradable sludge (195 ± 3.7 NLCH4/kgVSadded) that after thermal pre-treatment resulted in an increase in methane production of 9 %, which was similar to the WAS coming from the full-scale WWTP. It was concluded that not only the bioconversion but also the response to mild thermal pre-treatment of lab-grown sludge was determined by the composition of the growth media. Subject Activated sludgeAnaerobic digestionDomestic wastewaterLab-grown sludgePre-treatmentSynthetic wastewater To reference this document use: http://resolver.tudelft.nl/uuid:3b978df5-cdf3-428b-89c5-85ccd373a180 DOI https://doi.org/10.1016/j.jenvman.2021.113491 ISSN 0301-4797 Source Journal of Environmental Management, 298 Part of collection Institutional Repository Document type journal article Rights © 2021 A. Gonzales, J.B. van Lier, M.K. de Kreuk Files PDF 1_s2.0_S030147972101553X_main.pdf 3.44 MB Close viewer /islandora/object/uuid:3b978df5-cdf3-428b-89c5-85ccd373a180/datastream/OBJ/view