Comammox activity dominates nitrification process in the sediments of plateau wetland

2021 ◽  
pp. 117774
Author(s):  
Dongdan Yuan ◽  
Lei Zheng ◽  
Qiuyang Tan ◽  
Xue Wang ◽  
Yuzi Xing ◽  
...  
Keyword(s):  
Plateau Wetland ◽  
Nitrification Process

Designing Experiments for Model Identification of the Nitrification Process

1991 ◽  
Vol 24 (6) ◽  
pp. 9-16 ◽  
Author(s):  
P. J. Ossenbruggen ◽  
H. Spanjers ◽  
H. Aspegren ◽  
A. Klapwijk
Keyword(s):  
Mechanistic Model ◽  
Nonlinear Differential Equations ◽  
Model Identification ◽  
Reaction Rates ◽  
Variable Coefficients ◽  
Model Specification ◽  
First Order ◽  
Interactive Behavior ◽  
Batch Tests ◽  
Nitrification Process

A series of batch tests were performed to study the competition for oxygen by Nitrosomonas and Nitrobacter in the nitrification of ammonia in activated sludge. Oxygen uptake rate (OUR) and dynamic (compartment) models describing the process are proposed and tested. The OUR model is described by a Monod relationship and the biogradation process by a set of first order nonlinear differential equations with variable coefficients. The results show a mechanistic model and ten reaction rates are sufficient to capture the interactive behavior of the nitrification process. Methods for model specification, calibrating, and testing the model and the design of additional experiments are described.

CHARACTERISATION OF THE NITRIFICATION PROCESS FOR DESIGN PURPOSES

1994 ◽  
Vol 30 (4) ◽  
pp. 47-56 ◽  
Author(s):  
O. Sinkjær ◽  
L. Yndgaard ◽  
P. Harremoës ◽  
J. L. Hansen
Keyword(s):  
Kinetic Theory ◽  
Nitrification Rate ◽  
Experimental Basis ◽  
Batch Tests ◽  
Mode Of Operation ◽  
Nitrification Process ◽  
Aerobic Reactor ◽  
The City ◽  
Specific Evaluation ◽  
Aerobic Sludge

Pilot plant experiments have been performed over a period of four years in order to establish an experimental basis for the upgrading of the treatment plants of the city of Copenhagen to nitrogen removal. The design chosen is based on the alternating mode of operation. Nitrification rates have been determined in batch tests on activated sludge extracted from the pilot plants and through the measuring of transient concentrations during the alternating mode of operation in the aerobic reactor. The data have been nonnalised to standard conditions by correcting them according to the kinetic theory. By monitoring the normalised nitrification rate it could be established that the nitrification process was occasionally inhibited. The aerobic sludge age required to maintain nitrification has been estimated. A specific evaluation has been made of the sensitivity of the required sludge age to the oxygen concentration and temperature.

Nitrogen Reduction – Volume Demand

1992 ◽  
Vol 25 (4-5) ◽  
pp. 233-240
Author(s):  
T. Palmgren
Keyword(s):  
Suspended Solids ◽  
Age Factors ◽  
Reduction Rate ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Aeration Tank ◽  
Nitrogen Reduction ◽  
Solids Concentration ◽  
Yearly Average ◽  
Nitrification Process

Due to the slow growth of nitrification bacteria at low temperatures, nitrogen reduction normally requires long hydraulic retention time during winter. Important for the nitrification process is the aerated sludge age. Factors influencing the sludge age are aerated volume, mixed liquor suspended solids concentration, organic loading and sludge yield. In an existing plant you cannot easily expand the volume and the load is difficult to decrease. But the suspended solids concentration can be increased by running the biological step with the contact stabilisation process. At the Käppala Association sewage treatment plant in Lidingö just outside Stockholm, one of the six aeration tanks has been reconstructed for full scale nitrogen removal experiments. In this tank the old aeration system has been replaced with rubber membrane diffusers. Further more there are several zones separated by walls in the tank. The tank can thereby be run with great flexibility. By running it with the contact stabilisation process, the sludge age has been improved by a factor between 1.5 and 2 and thereby it succeeds in keeping the nitrification bacteria in the system even during snow melting. At temperatures of about 9 °C and hydraulic retention times of less than 3 hours in the contact zone there has been a nitrification degree of up to 50 to 60 %. The experiment was conducted with a stabilisation zone of up to half the total volume of the aeration tank. The main purpose for the experiments during the winter seasons was to improve nitrification. Keeping the nitrifiers in the system had been a crucial problem during previous years. When the nitrifiers were lost with an increased flow and decreased temperature the nitrification process didn't restart until the temperature was increased and the load decreased. Usually this didn't occur until the middle of the summer meaning a loss of nitrification for up to six months. In Sweden there is a goal set for 50 % nitrogen reduction for the plants in the Stockholm region. At Käppala we manage to keep 60 to 70 % nitrogen reduction during the warm season, that is from July to December. If we can keep up the nitrification the whole year we can achieve 50 % as a yearly average under normal conditions even though we can't keep the nitrogen reduction rate as high during the cold season.

scholarly journals Nitrification Process in a Nuclear Wastewater with High Load of Nitrogen, Uranium and Organic Matter under ORP Controlled

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1607
Author(s):  
Mariano Venturini ◽  
Ariana Rossen ◽  
Patricia Silva Paulo
Keyword(s):  
Ammonia Oxidation ◽  
High Load ◽  
Nuclear Fuels ◽  
Monod Model ◽  
Nernst Equation ◽  
Nitrification Process ◽  
Real Wastewater ◽  
High Concentrations ◽  
Wastewater Samples ◽  
Very High

To produce nuclear fuels, it is necessary to convert uranium′s ore into UO2-ceramic grade, using several quantities of kerosene, methanol, nitric acid, ammonia, and, in low level, tributyl phosphate (TBP). Thus, the effluent generated by nuclear industries is one of the most toxic since it contains high concentrations of dangerous compounds. This paper explores biological parameters on real nuclear wastewater by the Monod model in an ORP controlled predicting the specific ammonia oxidation. Thermodynamic parameters were established using the Nernst equation to monitor Oxiders/Reductors relationship to obtain a correlation of these parameters to controlling and monitoring; that would allow technical operators to have better control of the nitrification process. The real nuclear effluent is formed by a mixture of two different lines of discharges, one composed of a high load of nitrogen, around 11,000 mg/L (N-NH4+-N-NO3−) and 600 mg/L Uranium, a second one, proceeds from uranium purification, containing TBP and COD that have to be removed. Bioprocesses were operated on real wastewater samples over 120 days under controlled ORP, as described by Nernst equations, which proved to be a robust tool to operate nitrification for larger periods with a very high load of nitrogen, uranium, and COD.

Removal of Ammonia Nitrogen from Domestic Wastewater Using Vertical Aerated Limestone Filter

2015 ◽  
Vol 752-753 ◽  
pp. 232-237
Author(s):  
Rafidah binti Hamdan ◽  
Izzati Izwani Ibrahim ◽  
Ain Nabila Abdul Talib
Keyword(s):  
Dissolved Oxygen ◽  
Water Body ◽  
Nutrient Removal ◽  
Domestic Wastewater ◽  
Ammonia Nitrogen ◽  
Maintenance Cost ◽  
Effluent Quality ◽  
Filter System ◽  
Nitrification Process ◽  
Final Effluent

Nitrogen is a naturally occurring element that is essential for growth and reproduction in both plants and animals. Excessive concentrations in the water body can cause excessive growth of algae and other plants, leading to accelerate eutrophication of lakes, and occasional depletion of dissolved oxygen. To remove nitrogen conventionally from domestic wastewater requires a high cost technology due to consumption of chemicals, high operational and maintenance cost. Therefore, an alternative low cost treatment technology particularly for nutrient removal including nitrogen removal system has been developed to improve the final effluent quality that is an aerated rock filter system. However, the optimization study under warm climate has not yet been developed. Hence, the present study was carried out to investigate the removal of ammonia nitrogen (AN) from domestic wastewater through nitrification process using a lab-scale vertical aerated limestone filter. Domestic wastewater sample used in this study was collected from Taman Bukit Perdana Wastewater Treatment Plant (WWTP), Batu Pahat, Johor owned by IWK. The experiment has been carried out for 10 weeks. The influent and effluent of the vertical aerated limestone filter system have been sampled and analyzed on biweekly basis for selected parameters including AN, Total Kjedhal Nitrogen (TKN), pH, alkalinity, temperature and dissolved oxygen to monitor the effectiveness of the filter. Results from this study show that nitrification process has took place within the aerated limestone filter as the results from laboratory experiments show that AN in wastewater was oxidized to nitrate and efficiently removed as the removal of AN was ranged from 85 % to 92 % and the removal percentage of TKN was ranged from 83.52 % - 91.67 %. The temperature was in the average of 26.3oC±0.75, pH value average of , DO was from 6.64 mg/L to 7.75 mg/L , and the alkalinity was from 15 to 110 mg / l as CaCO3 . Therefore, from this study it can be concluded that aerated rock filter system has high potential in removing AN and TKN. It is also able to produce a good final effluent quality which is comply with the effluent requirement for nutrient removal in wastewater under the Environmental Quality Act (Sewage) Regulations, 2009 that is safe to be released to the water body.

Responses of avian community to plateau wetland degradation in Zoige

2021 ◽  
Vol 41 (2) ◽  
Author(s):  
包新康，廖继承，索郎夺尔基，孙元海，丁励，卓玛姐，玛吉措 BAO Xinkang
Keyword(s):  
Wetland Degradation ◽  
Avian Community ◽  
Plateau Wetland

scholarly journals Dissipation of nitrapyrin (nitrification inhibitor) in subtropical soils

2019 ◽  
Vol 52 (2) ◽  
pp. 173
Author(s):  
Anjana Srivastava
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Quantitative Analysis ◽  
Environmental Pollution ◽  
Nitrate Leaching ◽  
High Performance ◽  
Nitrification Inhibitor ◽  
Quechers Method ◽  
Subtropical Soils ◽  
Nitrification Process

<p>Nitrapyrin (2-chloro-6-(trichloromethyl)pyridine) is a specific nitrifiation inhibitor, applied in soils for reducing the nitrification process of nitrogenous fertilizers. The overall effect of nitrapyrin is enhancing the efficiency of nitrogenous fertilizers in soils and also controlling environmental pollution in water by preventing nitrate leaching in soils. Dissipation of nitrapyrin was evaluated in subtropical soils at two fortification levels of 2 and 4 µg∙g-1. The extraction of nitrapyrin was done by quick, easy, cheap, rugged and safe (QuEChERS) method and quantitative analysis – by high-performance liquid chromatography (HPLC). Nitrapyrin residues declined consistently with time in both types of soils and were not detectable (</p>

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