Nitrate removal processes in the riverbed during a single‐peak flood event

2021 ◽  
Vol 35 (2) ◽  
Author(s):  
Qihao Jiang ◽  
Guangqiu Jin ◽  
Hongwu Tang ◽  
Junzeng Xu ◽  
Qi Wei ◽  
...  
2021 ◽  
Author(s):  
Maryam Reza

Eutrophication is reported as the most important water quality issue around the world. The potential death of Lake Winnipeg, the world's ninth largest lake, is a dramatic exampe of this ecological disater in Canda. Property price devaluation, tourist repulsion, and toxicity due to eutrophication cause the annual economic losses over $3 billion in Europe, South and North America. The objective of this thesis is to develop an efficient biological nutrient removal reactor to be commercialized and used in the water/wastewater treatment industry. This bioreactor has a unique configuration which is filed as a US patent technology called "Compact Upright Bioreactor for the Elimination of Nutrients", invented by M. Alvarez Cuenca and M. Reza. It consists of four stages including Deaeration, Anoxic, Anaerobic and Aerobic where Do removal, denitrification and phosphorus removal processes take place respectively. The bioreactor performs very well obtaining 100% Do removal and 98% nitrate removal efficiency. The phosphorus removal process requires much longer operational period to reach steady state. The phosphorus removal process shows variable results having a maximum of 60% removal success.


2017 ◽  
Vol 17 (6) ◽  
pp. 1694-1702 ◽  
Author(s):  
Amos Nussinovitch ◽  
Cheinat Zohar-Perez ◽  
Zahi Rabinovitz ◽  
Jaap van Rijn

Abstract Nitrate may reach surface and ground waters as a consequence of agricultural activity and discharge of domestic and industrial waste. Among the various methods used for nitrate removal, denitrification, a process in which nitrate is biologically reduced to elemental nitrogen, is relatively reliable and inexpensive as compared to other physical and chemical nitrate removal processes. Denitrification is generally conducted with biofilters in which bacteria are either immobilized to the surface of insoluble carriers or are entrapped within an immobilization matrix. We examined the use of non-toxic and biodegradable natural hydrocolloids for entrapment of denitrifying bacteria. Gel beads containing starch and alginate were used for this purpose. Three types of gel beads were examined: (1) wet gel beads; (2) porous wet gel beads; and (3) freeze-dried gel beads. With respect to nitrate removal, wet and dried gel beads showed similar removal capacities. Porous beads demonstrated an advantage over regular gel beads only during the first of the approximately 3-month incubation period. The viability of the immobilized bacteria was only slightly affected during prolonged refrigerated storage of the beads. Compared to freeze-dried beads, production costs of wet beads are significantly reduced, so it is anticipated that such carriers will eventually lead to a method that can be applied on an industrial scale.


Desalination ◽  
2007 ◽  
Vol 204 (1-3) ◽  
pp. 46-62 ◽  
Author(s):  
Claudio Della Rocca ◽  
Vincenzo Belgiorno ◽  
Sureyya Meriç

Author(s):  
Mads Steiness ◽  
Søren Jessen ◽  
Sofie G. M. ’t Veen ◽  
Tue Kofod ◽  
Anker Lajer Højberg ◽  
...  

1995 ◽  
Vol 32 (3) ◽  
pp. 219-228 ◽  
Author(s):  
Zhu Tong ◽  
F. J. Sikora

A greenhouse experiment was conducted at Tennessee Valley Authority, Alabama, USA, in the summer of 1993 to investigate ammonium and nitrate removal processes in constructed wetlands. Microcosm wetlands cells were used in the study and consisted of plastic containers with 0.4 × 0.35 m2 surface area and 0.5 m depth. Two separate experiments were conducted. One experiment analyzed NH4-N removal and the other analyzed NO3-N removal. Nutrient solutions containing approximately 48 mg/l NH4-N or NO3-N were added in a batch mode to the wetland microcosms and the solution chemistry was analyzed with time. Treatments consisted of unplanted cells or cells planted with canarygrass (Phalaris arundinacea), reed (Phragmites communis), bulrush (Scirpus atrovirens georgianus) or typha (Typha latifolia). Another treatment consisted of added nutrient solutions containing or not containing C at 112 mg/l. In the NH4-N removal experiment, the rate of NH4-N removal occurred in the order: reed > canarygrass = bulrush > typha ≫ unplanted in wetland cells with and without C. The order of NH4-N removal was believed to be associated with the density of root biomass in the gravel. The greater the root biomass, the greater the chance for plant N uptake or nitrification mediated by O2 transport to the rhizosphere. In the NO3-N experiment, the rate of NO3-N removal occurred in the order: reed = canarygrass > typha = bulrush > unplanted cells. Labelled K15NO3 was used to trace the NO3-N removal process. By measuring the 15N in the plant biomass, the quantity of NO3-N removed via plant uptake was delineated from combined removal processes of denitrification and immobilization. In the treatments with C, 55 to 70% of the NO3-N was removed via denitrification and immobilzation. For bulrush, reed and typha, the quantity of NO3-N removed via denitrification and immobilization without added C was reduced to 14 to 30%. However, NO3-N removal via denitrification and immobilization remained high at 72% of added NO3-N in canarygrass cells due to high concentrations of organic C released from the canarygrass roots (15-20 mg/l C) that apparently did not limit denitrification or immobilization.


1994 ◽  
Vol 29 (4) ◽  
pp. 141-149 ◽  
Author(s):  
A. Bryce Cooper

The ability of two small wetlands to remove added nitrate was studied as part of a wider investigation into the feasibility of using a combined forest irrigation-wetland treatment system to meet strict receiving water limits. In laboratory microcosm experiments, wetland sediments removed nitrate at rates between 0.019 - 0.609 g m−2 d−1, with rates being dependent upon nitrate loading and the vegetation that supplied the decaying organic matter (Typha orientalis > Carex spp. > Azollafiliculoides). Denitrification could account for between 32 - 100% of the observed nitrate loss, indicating that in some microcosms other nitrate removal processes were operating. Additions of bromide (a conservative tracer) and nitrate to the two wetlands demonstrated more rapid nitrate loss in a Typha stand (decay coefficient, ke = 4.44 d−1) compared to loss in an Azolla pond (ke = 1.1 d−1). The time course of bromide concentration at the wetland outlets, and its distribution within the wetlands, showed the presence of preferential flow paths and “dead” zones. This non-uniform flow is a common characteristic of wetlands and, in this case, may exert a major control on the scheme's overall nitrate removal efficiency.


2021 ◽  
Author(s):  
Maryam Reza

Eutrophication is reported as the most important water quality issue around the world. The potential death of Lake Winnipeg, the world's ninth largest lake, is a dramatic exampe of this ecological disater in Canda. Property price devaluation, tourist repulsion, and toxicity due to eutrophication cause the annual economic losses over $3 billion in Europe, South and North America. The objective of this thesis is to develop an efficient biological nutrient removal reactor to be commercialized and used in the water/wastewater treatment industry. This bioreactor has a unique configuration which is filed as a US patent technology called "Compact Upright Bioreactor for the Elimination of Nutrients", invented by M. Alvarez Cuenca and M. Reza. It consists of four stages including Deaeration, Anoxic, Anaerobic and Aerobic where Do removal, denitrification and phosphorus removal processes take place respectively. The bioreactor performs very well obtaining 100% Do removal and 98% nitrate removal efficiency. The phosphorus removal process requires much longer operational period to reach steady state. The phosphorus removal process shows variable results having a maximum of 60% removal success.


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