Study on the Effect of Flow Velocity on the Denitrification of Groundwater

2015 ◽  
Vol 1092-1093 ◽  
pp. 933-937
Author(s):  
Xin Ran Jiang ◽  
Li Na Zheng ◽  
Xing Ai ◽  
Lin Zhang ◽  
Wei Nan Wu

Using the mixed filling reaction column, this article examines that the influence of different inlet flow rate on the removal of nitrate nitrogen in groundwater, respectively by 90mL/h, 150 mL/h, 210mL/h velocity, under 30 °C each run five days, comparativly studies the influence of velocity on denitrification. The results show that the flow rate has an important effect on the denitrification of water, when the water inlet velocity decreased from 150mL/h to 90mL/h, the concentration of nitrate nitrogen reaction column effluent decreased gradually, and the denitrification of nitrite nitrogen accumulation system has been in a low level, but the ammonia nitrogen accumulation only in the flow rate of 90mL/h, began when the flow rate decreased significantly; also increased from 90mL/h to 210mL/h, the effluent nitrate nitrogen concentration, nitrite nitrogen concentration and ammonia nitrogen concentration increased significantly.

2015 ◽  
Vol 1092-1093 ◽  
pp. 1068-1072
Author(s):  
Yi Feng Lei ◽  
Li Na Zheng ◽  
Xin Ran Jiang ◽  
Wei Nan Wu ◽  
Yi Ming Han

By zeolite column adsorption test process of nitrate pollution of groundwater, the research of three different inlet velocity of nitrate nitrogen removal, and the roles of nitrite nitrogen accumulation, zeolite adsorption of ammonia nitrogen and the influence of pH value changes, the results show that when the flow rate of 70 mL/h, the nitrate nitrogen concentration in the reaction column rising velocity under concentration less than before, but nitrate nitrogen concentration in the zeolite column has remained at about 3 mg/L, removal rate has remained at more than 95%; Nitrite nitrogen accumulation showed a trend of gradual decline, within the scope of flow rate of 90 mL/h, not affected by the late response, nitrite nitrogen concentration of 0.2 mg/L; As the reaction progresses, pH value gradually rose slightly, but still within the range of 6.0 to 8.0; Flow rate of 50 mL/h, zeolite adsorption of ammonia nitrogen effect is best.


2019 ◽  
Vol 19 (6) ◽  
pp. 1636-1642
Author(s):  
Sizhi Cao ◽  
Peigui Liu ◽  
Mingchao Liu ◽  
Gang Wang ◽  
Zaili Li ◽  
...  

Abstract In this study, column experiments in the laboratory were set up to examine how the concentrations of nitrate nitrogen, nitrite nitrogen, and ammonia nitrogen changed when a nitrate-rich solution was passed through a medium comprising zero-valent iron, activated carbon, zeolite, and coarse sand. We varied the proportions of the components of the medium to determine how it influenced the nitrate removal and nitrogen fractions. Three different scenarios were used, with: (1) iron, activated carbon, and coarse sand at a ratio of 3:1:6; (2) iron, activated carbon, and zeolite at a ratio of 3:1:6; and (3) iron, activated carbon, and zeolite at a ratio of 3:3:4. The nitrate nitrogen concentration decreased from 25 mg/L to 2 mg/L in the first scenario. Removal was better when zeolite was added to the medium as most of the nitrate nitrogen broke down to ammonia nitrogen, with nitrite nitrogen as an intermediate product. The results of the tests showed that nitrate removal was best when the medium was iron, activated carbon, and zeolite, mixed at a ratio of 3:1:6. This study provides a scientific reference for in situ remediation of nitrate pollution in groundwater.


2011 ◽  
Vol 374-377 ◽  
pp. 498-503
Author(s):  
Jin Lan Xu ◽  
Lei Wang ◽  
Jun Chen Kang ◽  
Ting Lin Huang ◽  
Yu Hua Dong

Abstract: Active barrier system (ABS) capping zeolite with large surface area and strong adsorption ability is an effective way to control eutrophication of lake since it can remove ammonia in the lake released by sediment. Influence of the initial nitrogen concentration on eliminating nitrogen load of europhia sediment capping with active barrier system (ABS) were studied through an investigation of the repairment results of serious pollution period (total nitrogen concentration up to 25.33 mg/L), moderate pollution period (14.39 mg/L) and the slight pollution period (3.47 mg/L) of the ancient Canal of Yangzhou. The results showed that: (1) zeolite F1 inhibition effect is stronger than zeolite F2. More TN were removed as the initial TN concentration increased and longer rapid inhibit period were presented with the increased initial TN concentration. (2) The ammonia nitrogen in sediment could be rapidly released into the overlying water, and with lower initial TN concentration in source water, more ammonia would be released from the sediment. Long time treatment was necessary to inhibit the release of ammonia completely if the water showed a high initial TN concentration. (3) After covering zeolite, the total nitrogen in the overlying water were removed mainly through nitrification and denitrification. At the initial TN concentration of 3.47 mg/L, 14.39 mg/L, 25.88 mg/L, 61%, 45% and 52% of TN were removed by the conversion of ammonia to nitrogen gas, however, others left in water as nitrate nitrogen and nitrite residues, and 90% was nitrate nitrogen.


2012 ◽  
Vol 433-440 ◽  
pp. 18-23
Author(s):  
Xiao Liu ◽  
Yuan Fu Cao ◽  
Ti En Zhang

Experiments of the valve bridge are carried out and the boiling states are investigated, to study the boiling heat transfer in cylinder head jacket. The effects of inlet flow rate and temperature on boiling heat flux are analyzed, as well as the thickness of fire deck. The results show that the inlet velocity has little effect on the velocity in valve bridge zone, even the velocity in the valve bridge zone can strongly affect on boiling heat transfer. The results can offer references to practical application in power-enhanced diesel engine.


Author(s):  
О.В. Харькина ◽  
К.Р. Искалиева ◽  
Е.В. Малич

Проведено сравнение результатов расчета аэротенков по модели ATV (Standard ATV-DVWK-A131 E «Dimension of Single-Stage Activated Sludge Plants 2000»), которая является стохастической «табличной» моделью, и по модели ASM2d, которая относится к теоретическим и описывает, в отличие от ATV, процессы биологической очистки сточных вод с помощью формул ферментативной кинетики. Расчеты выполнены для одних и тех же входных данных. Результаты расчетов показали существенную ограниченность использования модели ATV. Данная модель, как изначально указано авторами в ее описании, рассчитывает аэротенки только на единственное значение качества очищенной воды по аммонийному азоту 1 мг/л и не рассчитывает аэротенки на нитриты. Более того, сравнение ATVс ASM2d показало, что и достижение указанного качества очищенной воды по аммонийному азоту 1 мг/л возможно только при конкретных значениях кинетических констант, которые были определены авторами в данной статье, а изменение хотя бы одного из кинетических параметров сточных вод приводит к увеличению необходимого значения аэробного возраста активного ила и, как следствие, расчетного объема аэробной зоны на десятки процентов, что доказывает риск недостижения требуемого качества очищенной воды при использовании модели ATVдаже на концентрацию аммонийного азота 1 мг/л. С учетом того, что методика ATV не рассчитывает аэротенки на качество очищенных вод по нитритам, результаты проведенного нами расчета показывают, что предлагаемые в ATVзначения аэробного возраста активного ила 4,05 суток для температуры 17 ºС позволят достичь качество очищенной воды по азоту нитритов 0,35–0,52 мг/л N–NO2. Это доказывает невозможность использования ATV, если даны требования к качеству очищенной воды по нитритам. Авторами на основании проведенных расчетов сделаны выводы о риски недостижения качества очищенной воды по аммонийному азоту, как и 1 мг/л при использовании ATV, из-за того, что ATVявляется стохастической моделью, то есть все представленные в данной методике зависимости были определены для конкретных условий проведения работ. Более того, как и указано в описании ATV, данная методика применима, даже в ограниченных условиях, строго для городских сточных вод. Проведенные расчеты показали, что при наличии требований к качеству очищенной воды по нитритам, вне зависимости от значений требуемых концентраций нитритов, методика ATVне подходит вообще, при этом ASM2dс учетом того, что она основывается на формулах ферментативной кинетики, позволяет рассчитывать аэротенки на любое требуемое качество очищенной воды как по аммонийному азоту, так и по азоту нитритов и применима для любого типа сточных вод. A comparison is made of the results of calculating aeration tanks by ATV model (Standard ATV-DVWK-A131 E «Dimension of Single-Stage Activated Sludge Plants 2000»), that is a stochastic «table» model, and by ASM2d model, that is referred to as theoretical and describes, unlike ATV, biological wastewater treatment processes using enzymatic kinetics formulas. Calculations are performed for the same input data. The calculation results show essentially limited use of ATV model; this model, as originally given in the description of this model by the designers, provides for calculating aeration tanks only for a single value of the effluent quality in terms of ammonia nitrogen as 1 mg/l and does not provide for calculating aeration tanks in terms of nitrites. Moreover, the comparison of ATV and ASM2d show that achieving the specified quality of effluent in terms of ammonia nitrogen as 1 mg/l is possible only at specific values ​​of the kinetic constants determined by the authors in this article; whereas, any change in at least one kinetic parameter of the wastewater results in an increase in the required aerobic age of activated sludge and, as a consequence, in the calculated volume of the aerobic zone by tens of percent, which proves the risk of not achieving the required effluent quality while using ATV model even for ammonium nitrogen concentration of 1 mg/l. Taking into account the fact that ATV Method does not provide for calculating aeration tanks for the effluent quality in terms of nitrites, the results of our calculation show that the aerobic age of activated sludge of 4.05 days for a temperature of 17 ºС proposed in ATV will make it possible to achieve the effluent quality in terms of nitrite nitrogen, 0.35–0.52 mg/l N–NO2, proving the unavailability of ATV, if the requirements to the effluent quality in terms of nitrites are specified. The authors, on the basis of the calculations, make conclusions about the risk of failure to achieve the effluent quality in terms of ammonia nitrogen as well as 1 mg/l while using ATV, because ATV is a stochastic model, that is, all dependencies presented in this method have been determined for the specific operating conditions. Moreover, as specified in the ATV description, this method, even in limited conditions, is applicable strictly for urban wastewater. The calculations show that if there are requirements for the effluent quality in terms of nitrites, regardless of the required concentration value of nitrites, the ATV method is absolutely not suitable, while ASM2d, taking into account the fact that it is based on the formulas of enzymatic kinetics, provides for calculating aeration tanks for any required effluent quality in terms of both ammonium nitrogen and nitrite nitrogen and is applicable for any type of wastewater.


2020 ◽  
Vol 12 (6) ◽  
pp. 2325
Author(s):  
Chao Zhang ◽  
Guozhen Zhang ◽  
Fuping Wu ◽  
Tianhong Zhou

This study was aimed to explore the effect of elastic filler on pollutant removal in each compartment of anaerobic baffled reactor (ABR), ABR with elastic filler, and ABR without elastic filler were compared. The result showed that elastic filler increased the removal rate of chemical oxygen demand (COD) and suspended solid (SS) in the first compartment, decreased the removal rate of COD and SS in the second and third compartments, and had little effect on the removal rate of COD and SS in the fourth compartment. Elastic filler increased the increase rate of ammonia nitrogen in the first and second compartments, decreased the increase rate of ammonia nitrogen in the third and fourth compartments; elastic filler had little effect on the nitrate nitrogen, nitrite nitrogen, total nitrogen and total phosphorus in each compartment of ABR. In general, elastic filler could improve the removal rate of COD and SS of ABR but had little effect on the increase rate of ammonia nitrogen, the removal rate of nitrate nitrogen, nitrite nitrogen, total nitrogen and total phosphorus. Elastic filler slightly increased the concentration of formic acid, acetic acid, propionic acid, and butyric acid in the first compartment of ABR, and slightly decreased the sum of formic acid and acetic acid in the second, hird and fourth compartments. Elastic filler did not change the composition of dissolved organic matter (DOM)in each compartment of ABR, but changed the kinds and contents of aromatic proteins, soluble microbial products and humic acids in each compartment of ABR. Elastic filler had little effect on ABR in the removal of aromatic proteins, but they could improve the removal rate of soluble microbial products and humicacids. Elastic filler slightly increased the degree of DOM humification (or maturity) in ABR effluent, but did not change the main source of humus like substance and DOM in ABR effluent.


1998 ◽  
Vol 38 (7) ◽  
pp. 135-142 ◽  
Author(s):  
Chin F. Chew ◽  
Tian C. Zhang

The feasibility of using electrokinetics coupled with a zero valent iron (Fe0) treatment wall to abiotically remediate nitrate-contaminated soils was investigated. Upon completion of each test run, the contaminated soil specimen was sliced into five parts and analyzed for nitrate-nitrogen, ammonia-nitrogen and nitrite-nitrogen. Nitrogen mass balance was used to determine the major transformation products. In control experiments where only electrokinetics was used at various constant voltages, 25 to 37% of the nitrate-nitrogen was transformed. The amount of nitrate-nitrogen transformed improved when a Fe0 wall (20 g or about 8-10% by weight) was placed near the anode. For test runs at various constant voltages, the amount of nitrate-nitrogen transformed ranged from 54 to 87%. By switching to constant currents, the amount of nitrate-nitrogen - transformed was about 84 to 88%. The major transformation products were ammonia-nitrogen and nitrogen gases. Nitrite-nitrogen was less than 1% in all experimental runs. Two localized pH conditions exist in the system, a low pH region near the anode and a high pH region near the cathode. Placing of an iron wall near the anode increases the pH in that area as time increases. Movement of the acid front did not flush across the cathode. This research has demonstrated that the electrokinetics/iron wall process can be used to remediate nitrate-contaminated groundwater.


2017 ◽  
Vol 76 (2) ◽  
pp. 396-412 ◽  
Author(s):  
Su-jin Lu ◽  
Jian-huan Si ◽  
Chuan-ying Hou ◽  
Yu-si Li ◽  
Meng-meng Wang ◽  
...  

To provide a theoretical basis for alpine source lake protection, ten samples were taken from each lake annually from 2012 to 2015. Each year, the various species of nitrogen and phosphorus nutrients were measured. The average contents of nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total phosphorus, and total nitrogen in the four lakes are 0.195–0.0 mg/L, 0.038–0.143 mg/L, 0.004–0.168 mg/L, 0.006–0.740 mg/L, and 0.050–0.547 mg/L, respectively. The total phosphorus contents in Eling Lake, Longbao Lake and Sea Star were higher than Class I water quality standards, and the total nitrogen contents in Eling Lake, Sea Star and Zhaling Lake were higher than Class I water quality standards as well. The concentration contour maps of the nitrate nitrogen, ammonia nitrogen, nitrite nitrogen, total phosphorus and total nitrogen showed that the indicators of the four lakes in the east, the west, and the center of the lake did not have the same trend. From 2012 to 2015, each of the measured nutrients showed a rising trend year by year. The four lakes are polluted by both endogenous and exogenous pollution, and it is necessary to limit the exogenous pollution and protect the alpine lakes immediately.


2011 ◽  
Vol 138-139 ◽  
pp. 1050-1055 ◽  
Author(s):  
Li Li Dong ◽  
Ji Guo Huang ◽  
Meng Sun

Aimed at the current problems of capacious of hydrotreater, susceptible to plugging by microbe and the accumulation of ammonia or nitrite nitrogen in aquaculture, the aquarium (contain with the water treatment processor) using physical filtration + biodegradation + activated carbon adsorption complex process was devised to treat aquaculture for recycle. Under different working conditions, the effects of water temperature, hydraulic retention time (HRT), air flow and aeration mode on removal efficiency of ammonia, nitrite nitrogen and nitrate nitrogen (three nitrogen) in aquaculture. The test results showed that sludge yielding in the hydrotreater was low and hydrotreater was insusceptible to be plug. In addition, under the conditions of water temperature 25°C, air flow 1.5L/min,HRT 1.5h and intermittent aeration (aerating once every 1h), the removal rate of ammonia nitrogen , nitrate nitrogen and nitrite nitrogen was over 97.5% ,96% and 98.7% respectively, it means the three nitrogen was not detected. Therefore, the incorporated aquarium could permanently preserved favorable living environment for fish and could provide technological security for three nitrogen remove of fish farm water and for intensifying water recycle.


1997 ◽  
Vol 36 (10) ◽  
pp. 73-78 ◽  
Author(s):  
Joanna Surmacz-Górska ◽  
Andrzej Cichon ◽  
Korneliusz Miksch

Shorter nitrification is reached through Nitrobacter bacteria activity inhibition. Nitrobacter bacteria responsible for nitrite nitrogen oxidation are sensitive to free ammonium. The presence of free ammonium depended on a high ammonia nitrogen concentration in wastewater and its pH. It was the pH of the wastewater that was the decisive parameter in Nitrobacter bacteria activity inhibition in stable temperatures and at stable ammonia nitrogen concentrations. Reaction control in the aeration phase of the treatment process guaranteed the concentration of free ammonium within the 1 to 6 mg NH3/l range and at the same time concentration of free nitrous acid did not exceed 0.04 mg HNO2/l. It allowed nitrification to be significantly shortened and to receive build-up of nitrite nitrogen up to 300 mg NO2-N/l. Nitrification rate was about 0.06 g N/g MLSS·d. Measured oxidation rates of particular groups of nitrifying bacteria as oxygen uptake rates by Nitrosomonas and Nitrobacter bacteria respectively made control of shorter nitrification easier and gave insight into the activity of both nitrifier groups.


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