Way for Intensifying the Process of Anaerobic Bioconversion by Preliminary Hydrolysis and Increasing Solid Retention Time

2021 ◽  
pp. 1195-1203
Author(s):  
Andrey Kovalev ◽  
Dmitriy Kovalev ◽  
Vladimir Panchenko ◽  
Valeriy Kharchenko ◽  
Pandian Vasant
Keyword(s):  
Retention Time ◽  
Solid Retention Time ◽  
Anaerobic Bioconversion

scholarly journals RETRACTED: Effect of the solid retention time in the obtention of polyhydroxyalkanoates [version 1; peer review: awaiting peer review]

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 1210
Author(s):  
Rolando Calero ◽  
Manuel Martínez
Keyword(s):  
Peer Review ◽  
Retention Time ◽  
Editorial Team ◽  
Solid Retention Time ◽  
Link Type ◽  
Academic Record

At the request of the authors, the article titled "Effect of the solid retention time in the obtention of polyhydroxyalkanoates" [version 1; peer review: awaiting peer review]. F1000Research 2021, 10:864 (https://doi.org/10.12688/f1000research.28852.1) has been retracted from F1000Research. Since publication of the article, the corresponding author has notified the Editorial team that this work was originally performed at University of A Coruña with the involvement of María C. Veiga and Christian Kennes, who were not notified regarding the submission of this manuscript or listed as authors. After discussion with all parties, including contact with the corresponding author’s institution, it was agreed that the article would be retracted in order to correct the academic record. As the article contains content which potentially should not have been made publicly available the content of the article has been removed. The authors apologise for this honest error.

Influence of solid retention time on the rheology of MBR sludge

2007 ◽  
Vol 56 (8) ◽  
pp. 151-159 ◽  
Author(s):  
C. Giordano ◽  
A. Pollice ◽  
G. Laera ◽  
D. Saturno ◽  
G. Mininni
Keyword(s):  
Retention Time ◽  
Apparent Viscosity ◽  
Biomass Concentration ◽  
Rheological Behaviour ◽  
Solid Material ◽  
Design Parameters ◽  
Rheological Characterization ◽  
Solid Retention Time ◽  
The One ◽  
Definition Of

The rheological characterization is of crucial importance in sludge management both for biomass dewatering and stabilization purposes and for the definition of design parameters for sludge handling operations. The sludge retention time (SRT) has a significant influence on biomass properties in biological wastewater treatment systems and in particular in membrane bioreactors (MBR). The aim of this work is to compare the rheological behaviour of the biomass in a membrane bioreactor operated under different SRT. A bench scale MBR was operated for four years under the same conditions except for the SRT, that ranged from 20 days to complete sludge retention. The rheological properties were measured over time and the apparent viscosity was correlated with the concentration of solid material under equilibrium conditions. The three models most commonly adopted for rheological simulations were evaluated and compared in terms of their parameters. Steady state average values of these parameters were related to the equilibrium biomass concentration (MLSS). The models were tested to select the one better fitting the experimental data in terms of Mean Root Square Error (MRSE). The relationship between the apparent viscosity and the shear rate, as a function of solid concentration, was determined and proposed.

Influence of HRT (hydraulic retention time) and SRT (solid retention time) on the hydrolytic pre-treatment of urban wastewater

2001 ◽  
Vol 44 (4) ◽  
pp. 7-14 ◽  
Author(s):  
P. Ligero ◽  
A. De Vega ◽  
M. Soto
Keyword(s):  
Retention Time ◽  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
Phase Iii ◽  
Urban Wastewater ◽  
Solid Retention Time ◽  
Start Up ◽  
Pre Treatment ◽  
Two Parameters ◽  
Hydrolysis Of

This work presents the results obtained from a study on the pretreatment of urban wastewater using a digester that acted as a system for the retention of solids (sedimentation-filtration), hydrolysis of the retained solids and acidification of the dissolved substances. After start-up (Phase I), the digester was operated at hydraulic retention times (HRT) of 4.4, 3.4 and 2.2 h and at solid retention times (SRT) of 24, 16 and 14 d, during Phases II, III and IV, respectively. The retention and removal of suspended solids (SS) was maintained slightly above 60%, independently of HRT and SRT. Conversely, eliminated chemical oxygen demand (COD) decreased slightly upon reducing HRT and SRT. The influence of these two parameters on the generation of volatile fatty acids (VFA) is more notable, reaching effluent VFA concentration of 29 (Phase II), 96 (Phase III), and 107 (Phase IV) mg COD/l. VFA to SS generation ratios were 0.13 (II), 0.35 (III), and 0.48 (IV) g VFACOD/g SS added. Optimum values were reached at an HRT of 2.2 h. Taking 100 kg influent COD as a base, the conversion of different kinds of COD was as follows (in kg influent:kg effluent): VFACOD (4:17), non-VFA soluble COD (45:23), VSSCOD (51:23). Simultaneously to these conversions, 2 kg VSSCOD are generated as purge stream and 35 kg COD are eliminated during the process.

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