Microalgae-bacteria aggregates: effect of the hydraulic retention time on the municipal wastewater treatment, biomass settleability and methane potential

2016 ◽  
Vol 91 (11) ◽  
pp. 2862-2870 ◽  
Author(s):  
Juan S Arcila ◽  
Germán Buitrón
2011 ◽  
Vol 418-420 ◽  
pp. 717-720
Author(s):  
Ming Yan Shi ◽  
Dong Hua Mo ◽  
Kang Sheng He ◽  
Jing Peng Li

In order to ensure the stable and standard discharge of mixed nitrogen sewage, Guangzhou Datansha Wastewater Treatment Plant has made a test using an inverted A2/ O process, with the actual Wastewater as entry water. When the ratio of mixed fecal sewage is 0.33%, the results showed that, extending the HRT(Hydraulic Retention Time) can help to enhance the effect of removing nitrogen, and HRT should be ensured at least 8 hours under the test conditions. And the increase of the concentration of dissolved oxygen can promote the effect of removing nitrogen ranging from 1.0 to 1.5 mg/L. And the sludge reflux ratio should be remained at 60%. Besides, the growth of sludge age has positive effect on nitrification, so the sludge age should be controlled in more than 20 days under the experimental conditions.


2017 ◽  
Vol 77 (3) ◽  
pp. 714-720 ◽  
Author(s):  
J. C. Leyva-Díaz ◽  
A. Rodríguez-Sánchez ◽  
J. González-López ◽  
J. M. Poyatos

Abstract A membrane bioreactor (MBR) and a hybrid moving bed biofilm reactor-membrane bioreactor (hybrid MBBR-MBR) for municipal wastewater treatment were studied to determine the effect of salinity on nitrogen removal and autotrophic kinetics. The biological systems were analyzed during the start-up phase with a hydraulic retention time (HRT) of 6 h, total biomass concentration of 2,500 mg L−1 in the steady state, and electric conductivities of 1.05 mS cm−1 for MBR and hybrid MBBR-MBR working under regular salinity and conductivity variations of 1.2–6.5 mS cm−1 for MBR and hybrid MBBR-MBR operating at variable salinity. The variable salinity affected the autotrophic biomass, which caused a reduction of the nitrogen degradation rate, an increase of time to remove ammonium from municipal wastewater and longer duration of the start-up phase for the MBR and hybrid MBBR-MBR.


2011 ◽  
Vol 14 (1) ◽  
pp. 56-64
Author(s):  
Uan Khac Do ◽  
Banu J. Rajesh ◽  
Ick T. Yeom

Sludge production in the membrane bioreactor treating municipal wastewater can be estimated from the kinetic equation which describes a relationship between sludge concentration and substrate, decay coefficient, sludge retention time and hydraulic retention time. Based on the experimental data and using the mathematical approximate method, the theoretical yield factor (Y) and the decay coefficient (kd) were found to be 0.33 mg VSS/mg COD and 0.04 1/day, respectively. Sludge production in the system can be estimated from the obtained kinetic equation. The calculated values were fluctuated around the measured ones. This result proved the potential application of the obtained equation for estimation of the biomass concentration and kinetic parameters in the wastewater treatment systems using membrane bioreactor technology.


2017 ◽  
Vol 8 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Xiaojie Mei ◽  
Zhiwei Wang ◽  
Yan Miao ◽  
Zhichao Wu

Abstract Anaerobic membrane bioreactor (AnMBR) processes are a promising method of recovering energy from municipal wastewater. In this study, a pilot-scale AnMBR with extremely short hydraulic retention time (HRT = 2.2 h) was operated at a flux of 6 L/(m2h) for 340 days without any membrane cleaning. The average value achieved for chemical oxygen demand (COD) removal was 87% and for methane yield was 0.12 L CH4/gCODremoved. Based on mass balance analysis, it was found that about 30% of total influent COD was used for methane conversion, 15% of COD for sulfate reduction, 10% for biomass growth and 10–20% of COD remained in the effluent. Microbial community analyses indicated that seasonal changes of feedwater (in terms of organic components and temperature) led to the variations of microbial community structures. Among the bacterial communities, Chloroflexi, Proteobacteria and Bacteroidetes were the three most predominant phyla. In the archaeal consortia, WCHA1-57 and Methanobacterium surpassed Methanosaeta and Methanolinea to become the predominant methanogens during the long-term operation of short HRT. The sulfate-reducing bacteria, accounting for less than 2% of total abundance of bacteria, might not be the dominant competitor against methanogens.


Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 967
Author(s):  
Yerkanat N. Kanafin ◽  
Dinara Kanafina ◽  
Simos Malamis ◽  
Evina Katsou ◽  
Vassilis J. Inglezakis ◽  
...  

Currently, there is growing scientific interest in the development of more economic, efficient and environmentally friendly municipal wastewater treatment technologies. Laboratory and pilot-scale surveys have revealed that the anaerobic membrane bioreactor (AnMBR) is a promising alternative for municipal wastewater treatment. Anaerobic membrane bioreactor technology combines the advantages of anaerobic processes and membrane technology. Membranes retain colloidal and suspended solids and provide complete solid–liquid separation. The slow-growing anaerobic microorganisms in the bioreactor degrade the soluble organic matter, producing biogas. The low amount of produced sludge and the production of biogas makes AnMBRs favorable over conventional biological treatment technologies. However, the AnMBR is not yet fully mature and challenging issues remain. This work focuses on fundamental aspects of AnMBRs in the treatment of municipal wastewater. The important parameters for AnMBR operation, such as pH, temperature, alkalinity, volatile fatty acids, organic loading rate, hydraulic retention time and solids retention time, are discussed. Moreover, through a comprehensive literature survey of recent applications from 2009 to 2021, the current state of AnMBR technology is assessed and its limitations are highlighted. Finally, the need for further laboratory, pilot- and full-scale research is addressed.


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