title: Evaluating sludge minimization caused by predation and viral infection based on the extended activated sludge model No. 2d.
abstract: The Activated Sludge Model No. 2d (ASM2d) was extended to incorporate the processes of both predation and viral infection. The extended model was used to evaluate the contributions of predation and viral infection to sludge minimization in a sequencing batch reactor (SBR) system enriching polyphosphate-accumulating organisms (PAOs). Three individual decay processes formulated according to the general model rules were used in the extended model. The model was firstly calibrated and validated by different experimental results. It was used to evaluate the potential extent of predation and viral infection on sludge minimization. Simulations indicate that predation contributes roughly two times more to sludge minimization than viral infection in the SBR system enriching PAOs. The sensitivity analyses of the selected key parameters reveal that there are thresholds on both predation and viral infection rates, if they are too large a minimal sludge retention time is obtained and the effluent quality is deteriorating. Due to the thresholds, the contributions of predation and viral infection to sludge minimization are limited to a maximal extent of about 21% and 9%, respectively. However, it should be noted that the parameters concerning predation and viral infection were not calibrated separately by independent experiment in our study due to the lack of an effective method, especially for the parameters regarding viral infection. Therefore, it is essential to better evaluate these parameters in the future.
authors.affiliation: Key Laboratory of Urban Stormwater System and Water Environment/R & D Centre for Sustainable Environmental Biotechnology, Beijing University of Civil Engineering and Architecture, Ministry of Education, 1 Zhanlanguan Road, Xicheng District, Beijing 100044, PR China. xdhao@hotmail.com
authors.forename: Xiaodi
authors.initials: X
authors.lastname: Hao
authors.forename: Qilin
authors.initials: Q
authors.lastname: Wang
authors.forename: Yali
authors.initials: Y
authors.lastname: Cao
authors.forename: Mark C M
authors.initials: MC
authors.lastname: van Loosdrecht
mesh_terms: D000818:Animals; D001419:Bacteria / Q000302:isolation & purification; D002138:Calibration; D017404:In Situ Hybridization, Fluorescence; D008962:Models, Theoretical; D011235:Predatory Behavior; D012722:Sewage; D014777:Virus Diseases / Q000635:transmission*; D014871:Water Microbiology
chemical_list: D012722:Sewage