scholarly journals Simultaneous removal of phosphorus and dissolved organic matter from a sludge in situ reduction process effluent by coagulants

RSC Advances ◽  
2017 ◽  
Vol 7 (67) ◽  
pp. 42305-42311 ◽  
Author(s):  
Ying An ◽  
Zhen Zhou ◽  
Weimin Qiao ◽  
Wei Pan ◽  
Zhihui Chen

Owing to the long solids retention time and effective sludge decay, the increase in the amount of phosphorus and dissolved organic matter (DOM) in effluents is a major obstacle to the sludge in situ reduction process.

2018 ◽  
Vol 54 (4B) ◽  
pp. 200
Author(s):  
Nguyen Xuan Quynh Nhu

Combined system of Anaerobic/Anoxic/Oxic reactor with Biological Aerated Filter (A2/O – BAF) is used to enhance simultaneous removal of nitrogen and phosphorus on aquatic product processing wastewater treatment. A2/O reactor was operated with short solids retention time employed mainly for removal of organic matter and phosphorus together with denitrification and BAF with long solids retention time employed mainly for nitrification. The model of combined A2/O – BAF system made from polyacrylic with the capacity of 49.5 liters was operated with hydraulic retention time decreased from 19.2 to 9.6 hours and organic loading rates increased from 0.50 to 1.0 kgCOD/m3/day.  The results showed that the model not only treated organic matter well but also removed nearly completely both nitrogen and phosphorus. For loading rate of 0.75 kgCOD/m3/day, treatment efficiencies of COD, NH4+-N, TN, TP of the model were the highest as 91.02, 96.82, 84.08, 86.66  %, respectively and output values of these parameters were within the limits of QCVN 11:2008/BTNMT, column A.


2014 ◽  
Vol 80 (19) ◽  
pp. 6004-6012 ◽  
Author(s):  
Karoline Wagner ◽  
Mia M. Bengtsson ◽  
Katharina Besemer ◽  
Anna Sieczko ◽  
Nancy R. Burns ◽  
...  

ABSTRACTHeadwater streams are tightly connected with the terrestrial milieu from which they receive deliveries of organic matter, often through the hyporheic zone, the transition between groundwater and streamwater. Dissolved organic matter (DOM) from terrestrial sources (that is, allochthonous) enters the hyporheic zone, where it may mix with DOM fromin situproduction (that is, autochthonous) and where most of the microbial activity takes place. Allochthonous DOM is typically considered resistant to microbial metabolism compared to autochthonous DOM. The composition and functioning of microbial biofilm communities in the hyporheic zone may therefore be controlled by the relative availability of allochthonous and autochthonous DOM, which can have implications for organic matter processing in stream ecosystems. Experimenting with hyporheic biofilms exposed to model allochthonous and autochthonous DOM and using 454 pyrosequencing of the 16S rRNA (targeting the “active” community composition) and of the 16S rRNA gene (targeting the “bulk” community composition), we found that allochthonous DOM may drive shifts in community composition whereas autochthonous DOM seems to affect community composition only transiently. Our results suggest that priority effects based on resource-driven stochasticity shape the community composition in the hyporheic zone. Furthermore, measurements of extracellular enzymatic activities suggest that the additions of allochthonous and autochthonous DOM had no clear effect on the function of the hyporheic biofilms, indicative of functional redundancy. Our findings unravel possible microbial mechanisms that underlie the buffering capacity of the hyporheic zone and that may confer stability to stream ecosystems.


2016 ◽  
Vol 92 ◽  
pp. 44-51 ◽  
Author(s):  
Halis Simsek ◽  
Murthy Kasi ◽  
Jae-Bom Ohm ◽  
Sudhir Murthy ◽  
Eakalak Khan

1994 ◽  
Vol 30 (6) ◽  
pp. 101-111 ◽  
Author(s):  
H. Siegrist ◽  
W. Gujer

Denitrification in the secondary clarifier can contribute substantially to the nitrogen removal of activated sludge systems. This is illustrated on two treatment plants with different secondary clarifier systems. A model to estimate denitrification capacity and to design activated sludge systems for nitrogen removal is developed and verified with data from two treatment plants. The model includes denitrification in the secondary clarifier, wastewater composition (soluble readily biodegradable COD, particulate degradable COD), oxygen input into the anoxic volume, temperature, and solids retention time (SRT). The influence of aerated grit chambers and primary sedimentation on denitrification is discussed.


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