scholarly journals Influence of hydraulic retention time on municipal wastewater treatment using microalgae-bacteria flocs in sequencing batch reactors

2021 ◽  
pp. 100884
Author(s):  
Hadi Soroosh ◽  
Ralf Otterpohl ◽  
Dieter Hanelt
Keyword(s):  
Wastewater Treatment ◽  
Retention Time ◽  
Municipal Wastewater ◽  
Hydraulic Retention Time ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Municipal Wastewater Treatment

Occurrence of Microthrix parvicella in sequencing batch reactors

2014 ◽  
Vol 69 (10) ◽  
pp. 1984-1995 ◽  
Author(s):  
Lana Mallouhi ◽  
Ute Austermann-Haun
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Volume Index ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Municipal Wastewater Treatment ◽  
Nitrogen And Phosphorus ◽  
Microthrix Parvicella

Sequencing batch reactors (SBRs) are known for high process stability and usually have a good sludge volume index (SVI). Nevertheless, in many SBRs in Germany for municipal wastewater treatment, scum and foam problems can occur, and SVI can be larger than 200 mL/g. The microscopic investigations of the activated sludge from plants with nitrogen and phosphorus removal have shown that Microthrix parvicella is dominant in the activated sludge in most of them. Studies showed that the optimum growth of M. parvicella is performed at a high sludge age (>20 d) and low sludge load in the range of 0.05–0.2 kg of biochemical oxygen demand per kg of total suspended solids per day (kg BOD5/(TSS·d)). The investigations in 13 SBRs with simultaneous aerobic sludge stabilization (most of them are operated with a system called differential internal cycle strategy sequential batch reactor (DIC-SBR)) show that M. parvicella is able to grow in sludge loads less than 0.05 kg BOD5/(kg TSS·d) as well. To optimize the operation of those SBRs, long cycle times (8–12 h) and dosing of iron salts to eliminate long-chain fatty acids are both recommended. This leads to better SVI and keeps M. parvicella at a low frequency.

Condition Analysis of Nitrogen Remove from the Mixture of Municipal Wastewater and Fecal Sewage

2011 ◽  
Vol 418-420 ◽  
pp. 717-720
Author(s):  
Ming Yan Shi ◽  
Dong Hua Mo ◽  
Kang Sheng He ◽  
Jing Peng Li
Keyword(s):  
Wastewater Treatment ◽  
Retention Time ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Hydraulic Retention Time ◽  
Treatment Plant ◽  
Reflux Ratio ◽  
Experimental Conditions ◽  
Test Conditions ◽  
Positive Effect

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.

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