Nitrogen removal in the Chaohu Lake, China: Implication in estimating lake N uptake velocity and modelling N removal efficiency of large lakes and reservoirs in the Changjiang River network

Adding a submerged zone (SZ) is deemed to promote denitrification during dry periods and thus improve NO3--N removal efficiency of a bioretention system. However, few studies had investigated the variation of nitrogen concentration in the SZ during dry periods and evaluated the effect of the variation on nitrogen removal of the bioretention system. Based on the experiment in a mesocosm bioretetion system with SZ, this study investigated the variation of nitrogen concentration of the system under 17 consecutive cycles of wet and dry alternation with varied rainfall amount, influent nitrogen concentration and antecedent dry periods (ADP). The results indicated that (1) during the dry periods, NH4+-N concentrations in SZ showed an exponential decline trend, decreasing by 50% in 12.9 ± 7.3 hours; while NO3--N concentrations showed an inverse S-shape decline trend, decreasing by 50% in 18.8 ± 6.4 hours; (2) during the wet periods, NO3--N concentration in the effluent showed an S-shape upward trend; and at the early stage of the wet periods, the concentration was relatively low and significantly correlated with ADP, while the corresponding volume of the effluent was significantly correlated with the SZ depth; (3) in the whole experiment, the contribution of nitrogen decrease in SZ during dry periods to NH4+-N and NO3--N removal accounted for 12% and 92%, respectively; and the decrease of NO3--N in SZ during the dry period was correlated with the influent concentration in the wet period and the length of the dry period.

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Upflow packed bed Anammox reactor used in two-stage deammonification of sludge digester effluent

Water Science & Technology ◽

10.2166/wst.2018.322 ◽

2018 ◽

Vol 78 (9) ◽

pp. 1843-1851 ◽

Cited By ~ 3

Author(s):

İ. Çelen-Erdem ◽

E. S. Kurt ◽

B. Bozçelik ◽

B. Çallı

Keyword(s):

Removal Efficiency ◽

Nitrogen Removal ◽

Municipal Wastewater ◽

Removal Rate ◽

Treatment Plant ◽

Packed Bed ◽

Municipal Wastewater Treatment ◽

Two Stage ◽

N Removal ◽

Total Nitrogen Removal

Abstract The sludge digester effluent taken from a full scale municipal wastewater treatment plant (WWTP) in Istanbul, Turkey, was successfully deammonified using a laboratory scale two-stage partial nitritation (PN)/Anammox (A) process and a maximum nitrogen removal rate of 1.02 kg N/m3/d was achieved. In the PN reactor, 56.8 ± 4% of the influent NH4-N was oxidized to NO2-N and the effluent nitrate concentration was kept below 1 mg/L with 0.5–0.7 mg/L of dissolved oxygen and pH of 7.12 ± 12 at 24 ± 4°C. The effluent of the PN reactor was fed to an upflow packed bed Anammox reactor where high removal efficiency was achieved with NO2-N:NH4-N and NO3-N:NH4-N ratios of 1.32 ± 0.19:1 and 0.22 ± 0.10:1, respectively. The results show that NH4-N removal efficiency up to 98.7 ± 2.4% and total nitrogen removal of 87.7 ± 6.5% were achieved.

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The Ammonia Nitrogen Removal Enhanced by Biological Aerobic Filter Packed with a Novel Lightweight Zeolite Particles

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.361-363.764 ◽

2013 ◽

Vol 361-363 ◽

pp. 764-767

Author(s):

Hai Tang ◽

Long Ouyang ◽

Xiang Zhao

Keyword(s):

Removal Efficiency ◽

Nitrogen Removal ◽

Ammonia Nitrogen ◽

Exponential Equation ◽

N Concentration ◽

N Removal ◽

Optimal Value ◽

Relationship Of ◽

The Relationship

The ammonia nitrogen (NH4-N) removal enhanced by biological aerobic filter (BAF) packed with novel micro-mesoporous lightweight zeolite particles (LZP) as carrier. The results showed that the biofilm can quickly grow up using LZP as media in the BAF. HLR of 1.2 was chosen as the optimal value under the average influent NH4+-N concentration of 24.6 mg/L, percent NH4-N removal of 87% and NLR of 0.24 kgN/m3.d was achieved. The kinetic performance of the LZP-BAF indicated that the relationship of NH4-N removal efficiency with the L could be described by an exponential equation (Ce/Ci=exp (-1.24/L0.344)).

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The Nitrogen-Removal Efficiency of a Novel High-Efficiency Salt-Tolerant Aerobic Denitrifier, Halomonas Alkaliphile HRL-9, Isolated from a Seawater Biofilter

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16224451 ◽

2019 ◽

Vol 16 (22) ◽

pp. 4451 ◽

Cited By ~ 1

Author(s):

Jilong Ren ◽

Chenzheng Wei ◽

Hongjing Ma ◽

Mingyun Dai ◽

Jize Fan ◽

...

Keyword(s):

Removal Efficiency ◽

Nitrogen Removal ◽

Nitrogen Balance ◽

High Efficiency ◽

Aerobic Denitrification ◽

Salt Tolerant ◽

N Accumulation ◽

Recirculating Aquaculture ◽

N Removal ◽

Recirculating Aquaculture Systems

Aerobic denitrification microbes have great potential to solve the problem of NO3−-N accumulation in industrialized recirculating aquaculture systems (RASs). A novel salt-tolerant aerobic denitrifier was isolated from a marine recirculating aquaculture system (RAS) and identified as Halomonas alkaliphile HRL-9. Its aerobic denitrification performance in different dissolved oxygen concentrations, temperatures, and C/N ratios was studied. Investigations into nitrogen balance and nitrate reductase genes (napA and narG) were also carried out. The results showed that the optimal conditions for nitrate removal were temperature of 30 °C, a shaking speed of 150 rpm, and a C/N ratio of 10. For nitrate nitrogen (NO3−-N) (initial concentration 101.8 mg·L−1), the sole nitrogen source of the growth of HRL-9, the maximum NO3−-N removal efficiency reached 98.0% after 24 h and the maximum total nitrogen removal efficiency was 77.3% after 48 h. Nitrogen balance analysis showed that 21.7% of NO3−-N was converted into intracellular nitrogen, 3.3% of NO3−-N was converted into other nitrification products (i.e., nitrous nitrogen, ammonium nitrogen, and organic nitrogen), and 74.5% of NO3−-N might be converted to gaseous products. The identification of functional genes confirmed the existence of the napA gene in strain HRL-9, but no narG gene was found. These results confirm that the aerobic denitrification strain, Halomonas alkaliphile HRL-9, which has excellent aerobic denitrification abilities, can also help us understand the microbiological mechanism and transformation pathway of aerobic denitrification in RASs.

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Nitrogen removal in baffled waste stabilization ponds

Water Science & Technology ◽

10.2166/wst.1996.0136 ◽

1996 ◽

Vol 33 (7) ◽

pp. 173-181 ◽

Cited By ~ 4

Author(s):

S. Muttamara ◽

U. Puetpaiboon

Keyword(s):

Removal Efficiency ◽

Nitrogen Removal ◽

Plug Flow ◽

Specific Area ◽

Pilot Scale ◽

Bacterial Biofilm ◽

Waste Stabilization Ponds ◽

Stabilization Ponds ◽

N Removal ◽

Waste Stabilization

This study evaluated nitrogen removal in Baffled Waste Stabilization Ponds (BWSPs) comprising laboratory and pilot-scale ponds with different number of baffles. The aim was to promote the waste stabilization pond practice for wastewater treatment in tropical countries by increasing nitrogen and organic carbon removal efficiency or reducing the land area requirement through the use of baffles which increased the biofilm biomass concentrations. The experiments started with a tracer study to find out the hydraulic characteristics of each pond. It was shown that the dispersion number decreased with increasing flow length and number of baffles which indicated more plug flow conditions. The deviation of actual HRT from theoretical HRT was computed and the flow pattern suggested the existence of an optimum spacing of baffles in BWSP units. The investigations further revealed that more than 65% TN and 90% NH3-N removal efficiencies were achieved at HRT of 5 days in a 6 baffled pond, which corresponds to the specific area of 34.88 m2m3. TN and NH3-N removal increased with increasing number of baffles in the BWSP units. Combined algal/bacterial biofilm grown on the baffles immersed in the ponds showed potential for increasing the extent of nitrification. COD removal increased with higher number of baffles with its maximum removal efficiency at 6 baffles. Compared with normal WSP, BWSP gave higher TN, NH3-N, COD and BOD5 removal efficiency. The effluent SS concentrations from the laboratory-scale 6 baffled pond were less than 20 mg/L at HRT of 3 days or more.

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Measurement of Denitrification in the Changjiang River

Environmental Chemistry ◽

10.1071/en04031 ◽

2004 ◽

Vol 1 (2) ◽

pp. 95 ◽

Cited By ~ 25

Author(s):

Weijin Yan ◽

Andrew E. Laursen ◽

Fang Wang ◽

Pu Sun ◽

Sybil P. Seitzinger

Keyword(s):

Nitrogen Removal ◽

Aquatic Ecosystems ◽

N2o Emission ◽

Changjiang River ◽

N2o Production ◽

Nitrogen Export ◽

Nitrogen Levels ◽

The Changjiang River ◽

The Three Gorges ◽

Plant Life

Environmental Context.Rivers are carrying an increased load of nitrogen-based matter (nitrates, nitrites) resulting from, among others, increased use of agricultural fertilizers. This nitrogen enrichment leads to a proliferation of plant life in the receiving water body, which in turn reduces the dissolved oxygen content and can cause the extinction of other organisms. Rivers can reduce their nitrogen levels through denitrification, the bacterially mediated transformation of dissolved nitrates and nitrites to gaseous N2 and N2O. This paper reports the first examination of denitrification in China’s largest river, the Changjiang (Yangtze) River, to understand the details of riverine denitrification and its role on controlling nitrogen export. Abstract.Rivers are an important link between terrestrial and aquatic ecosystems for nitrogen cycling, while denitrification plays a key role in riverine nitrogen removal. Denitrification was first examined in China’s largest river, the Changjiang River, by using a whole-reach method. The production rates of N2 by means of denitrification were 2.82 ± 1.18 and 5.74 ± 2.92 mmol(N) m−2 h−1 in October 2002 and March 2003, respectively, and the rates of N2O production were 1.98 ± 1.48 and 581 ± 1937 nmol(N) m−2 hr−1 in August and October 2002, respectively. Nitrogen removal through N2 and N2O emission accounted for 1–2% of NO3–-N flux through October 2002 to March 2003. Continued measurement throughout a whole year period after the construction of the Three Gorges Reservoir will provide more understanding of riverine denitrification and its role on controlling nitrogen export.

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Treatment characteristics and effects of nanoparticle zero-valent iron (nZVI) powder on nitrogen removal efficiency for sewage treatment

Water Quality Research Journal ◽

10.2166/wqrjc.2014.102 ◽

2014 ◽

Vol 49 (3) ◽

pp. 273-284 ◽

Cited By ~ 2

Author(s):

Mi-Sug Kim ◽

Dong-Heui Kwak

Keyword(s):

Removal Efficiency ◽

Nitrogen Removal ◽

Batch Reactor ◽

Nitrate Removal ◽

Sewage Treatment ◽

Synthetic Zeolite ◽

Zero Valent Iron ◽

Silica Sand ◽

Experimental Conditions ◽

N Removal

This study aims at estimating nanoparticle typed zero-valent iron (nZVI) process as an advanced nitrogen removal technique. To focus on investigating characteristics and effects of nZVI on nitrogen removal for sewage treatment, batch reactor experiments were conducted to reduce excessive nitrate nitrogen (NO3-N). To improve NO3-N removal efficiency and to find a supporter or alternative of nZVI, silica sand, synthetic zeolite, and a mixture of silica sand, synthetic zeolite, and nZVI were used in the experiments. As a result of this study, the chemical denitrification by nZVI attracted on the magnet surface may be useful for total nitrogen removal in conventional sewage and wastewater treatment plants under the optimal conditions, and application of silica sand also is an excellent adsorbent or media for N-component removal and a supporter as well. This study concludes the end product in this study may be nitrogen gas (N2) through Fe0 reaction with O2 and NO3− in aerobic nZVI (Fe0)–H2O system. Future study is required to examine the competition of nZVI between nitrate and many other compounds depending upon various experimental conditions for improving the nitrate removal efficiency and impeding the ammonium generation.

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