scholarly journals Nitrate removal from wastewater generated in wet Flue Gas Desulphurisation Systems (FGD) in coal-fired power generation using the heterotrophic denitrification method

2020 ◽  
Vol 31 (3) ◽  
pp. 27-34
Author(s):  
Krzysztof Iskra ◽  
Łukasz Krawczyk ◽  
Jan M. Miodoński ◽  
Dominika Wierzbicka-Kopertowska
Keyword(s):  
Flue Gas ◽  
Nitrate Nitrogen ◽  
Nitrate Removal ◽  
Oxygen Demand ◽  
Active Surface ◽  
Adaptation Period ◽  
Technological Parameters ◽  
Rate Test ◽  
High Degree ◽  
Heterotrophic Denitrification

Abstract The article presents an assessment of the possibilities of using the heterotrophic denitrification process to remove nitrates from wastewater produced in wet flue gas desulphurisation (FGD) installations and also its optimization in the scope of basic technological parameters. This kind of wastewater is characterized by high salinity (even up to 40,000 g/m3), high temperature (up to 50°C) and low biodegradability, which is expressed by the biochemical oxygen demand (BOD5). The experimental rig consisted of a storage tank and a bioreactor in the form of a bed with an apparatus for measuring basic parameters (temperature, pH, nitrate nitrogen). After an initial adaptation period, a high degree of nitrate nitrogen removal from wastewater (exceeding 95% reduction) was obtained with a reaction time of 180 minutes during the denitrification rate test (NUR). It was also determined that the optimal loading range of the active surface of the bed of 300 m2/m3 should be between 1.5–2.5 gN-NO3/m2·d. The results of the study show that when the required conditions for the development of microorganisms are provided, it is possible to fully adapt the denitrification biomass to the adverse composition of wastewater from wet FGD unit.

Nitrate removal by simultaneous sulfur utilizing autotrophic and heterotrophic denitrification under different organics and alkalinity conditions: batch experiments

2003 ◽  
Vol 47 (1) ◽  
pp. 237-244 ◽  
Author(s):  
S.E. Oh ◽  
M.S. Bum ◽  
Y.B. Yoo ◽  
A. Zubair ◽  
I.S. Kim
Keyword(s):  
Production Rate ◽  
Organic Compounds ◽  
Nitrate Nitrogen ◽  
Nitrogen Concentration ◽  
Nitrate Removal ◽  
Batch Reactors ◽  
Autotrophic Denitrification ◽  
Batch Experiments ◽  
Sulfate Production ◽  
Heterotrophic Denitrification

The effect of various organic compounds were tested using lab-scale batch reactors. At sufficient alkalinity, the initial nitrate nitrogen concentration of 100 mg/L was completely reduced in all batch reactors. Sulfate production decreased by the addition of organics. The concentration range of organics used in this experiment did not inhibit autotrophic denitrification except for propionate. Propionate inhibited autotrophic denitrification a little, indicated by a lower sulfate production rate. Biomass in suspension increased with higher initial organic concentrations, showing higher DOC consumption. As the concentration of organics increased, alkalinity increased accordingly. Under the conditions of low alkalinity, in the case of a control reactor without organics, only about 30% of the initial nitrate was reduced. With half the theoretically required dosage of methanol, the denitrification rates increased slightly. When ethanol, acetate, and propionate were used, denitrification went to completion. When excess organics was added, however, sulfate production was significantly decreased. Interestingly, even when small amounts of organics were added, autotrophic denitrification was promoted as indicated by the sulfate production.

A possibility of using nickel concentrate, obtained as a result of hydrometallurgical enrichment of manganese-containing raw materials, at steel alloying

2020 ◽  
Vol 76 (7) ◽  
pp. 709-715
Author(s):  
O. Yu. Kichigina
Keyword(s):  
Raw Materials ◽  
Experimental Studies ◽  
Selective Extraction ◽  
Technological Parameters ◽  
Nickel Iron ◽  
Nickel Recovery ◽  
Nickel Concentrate ◽  
Steel Alloying ◽  
High Degree ◽  
Comprehensive Processing

At production of stainless steel expensive alloying elements, containing nickel, are used. To decrease the steel cost, substitution of nickel during steel alloying process by its oxides is an actual task. Results of analysis of thermodynamic and experimental studies of nickel reducing from its oxide presented, as well as methods of nickel oxide obtaining at manganese bearing complex raw materials enrichment and practice of its application during steel alloying. Technology of comprehensive processing of complex manganese-containing raw materials considered, including leaching and selective extraction out of the solution valuable components: manganese, nickel, iron, cobalt and copper. Based on theoretical and experiment studies, a possibility of substitution of metal nickel by concentrates, obtained as a result of hydrometallurgical enrichment, was confirmed. Optimal technological parameters, ensuring high degree of nickel recovery out of the initial raw materials were determined. It was established, that for direct steel alloying it is reasonable to add into the charge pellets, consisting of nickel concentrate and coke fines, that enables to reach the through nickel recovery at a level of 90%. The proposed method of alloying steel by nickel gives a possibility to decrease considerably steel cost at the expense of application of nickel concentrate, obtained out of tails of hydrometallurgical enrichment of manganese-bearing raw materials, which is much cheaper comparing with the metal nickel.

Optimal operations for groundwater denitrification of drinking water using heterotrophic biological denitrification process

2006 ◽  
Vol 6 (2) ◽  
pp. 125-130
Author(s):  
C.-H. Hung ◽  
K.-H. Tsai ◽  
Y.-K. Su ◽  
C.-M. Liang ◽  
M.-H. Su ◽  
...  
Keyword(s):  
Drinking Water ◽  
Removal Efficiency ◽  
Nitrate Removal ◽  
Drinking Water Treatment ◽  
Nitrate Content ◽  
Source Water ◽  
Nitrogen Gas ◽  
Negative Effect ◽  
Denitrification Process ◽  
Heterotrophic Denitrification

Due to the extensive application of artificial nitrogen-based fertilizers on land, groundwater from the central part of Taiwan faces problems of increasing concentrations of nitrate, which were measured to be well above 30 mg/L all year round. For meeting the 10 mg/L nitrate standard, optimal operations for a heterotrophic denitrification pilot plant designed for drinking water treatment was investigated. Ethanol and phosphate were added for bacteria growing on anthracite to convert nitrate to nitrogen gas. Results showed that presence of high dissolved oxygen (around 4 mg/L) in the source water did not have a significantly negative effect on nitrogen removal. When operated under a C/N ratio of 1.88, which was recommended in the literature, nitrate removal efficiency was measured to be around 70%, sometimes up to 90%. However, the reactor often underwent severe clogging problems. When operated under C/N ratio of 1.0, denitrification efficiency decreased significantly to 30%. Finally, when operated under C/N ratio of 1.5, the nitrate content of the influent was almost completely reduced at the first one-third part of the bioreactor with an overall removal efficiency of 89–91%. Another advantage for operating with a C/N ratio of 1.5 is that only one-third of the biosolids was produced compared to a C/N value of 1.88.

Fenton degradation of Cartap hydrochloride: identification of the main intermediates and the degradation pathway

2015 ◽  
Vol 72 (7) ◽  
pp. 1198-1205 ◽  
Author(s):  
Kaixun Tian ◽  
Cuixiang Ming ◽  
Youzhi Dai ◽  
Kouassi Marius Honore Ake
Keyword(s):  
Aqueous Medium ◽  
Flue Gas ◽  
High Performance ◽  
Oxygen Demand ◽  
Nitrogen Monoxide ◽  
Degradation Pathway ◽  
Gas Chromatograph ◽  
Gas Analyzer ◽  
Fenton System ◽  
Long Chain

The advanced oxidation of Cartap hydrochloride (Cartap) promoted by the Fenton system in an aqueous medium was investigated. Based on total organic carbon, chemical oxygen demand and high-performance liquid chromatography, the oxidation of Cartap is quite efficient by the Fenton system. Its long chain is easily destroyed, but the reaction does not proceed to complete mineralization. Ion chromatography detection indicated the formation of acetic acid, propionic acid, formic acid, nitrous acid and sulfuric acid in the reaction mixtures. Further evidence of nitrogen monoxide and sulfur dioxide formation was obtained by using a flue gas analyzer. Monitoring by gas chromatograph-mass spectrometer demonstrated the formation of oxalic acid, ethanol, carbon dioxide, and l-alanine ethylamide. Based on these experimental results, plausible degradation pathways for Cartap mineralization in an aqueous medium by the Fenton system are proposed.

Biogeochemical indicators to evaluate pollutant removal efficiency in constructed wetlands

1997 ◽  
Vol 35 (5) ◽  
pp. 1-10 ◽  
Author(s):  
K. R. Reddy ◽  
E. M. D'Angelo
Keyword(s):  
Microbial Biomass ◽  
Removal Efficiency ◽  
Nitrate Removal ◽  
Oxygen Demand ◽  
Acid Soils ◽  
Pollutant Removal ◽  
Alkaline Soils ◽  
Organic C ◽  
Wetland Treatment ◽  
Biogeochemical Indicators

Wetlands support several aerobic and anaerobic biogeochemical processes that regulate removal/retention of pollutants, which has encouraged the intentional use of wetlands for pollutant abatement. The purpose of this paper is to present a brief review of key processes regulating pollutant removal and identify potential indicators that can be measured to evaluate treatment efficiency. Carbon and toxic organic compound removal efficiency can be determined by measuring soil or water oxygen demand, microbial biomass, soil Eh and pH. Similarly, nitrate removal can be predicted by dissolved organic C and microbial biomass. Phosphorus retention can be described by the availability of reactive Fe and Al in acid soils and Ca and Mg in alkaline soils. Relationships between soil processes and indicators are useful tools to transfer mechanistic information between diverse types of wetland treatment systems.

Study on the Gas Distribution Characters of the Outsize CO2 Absorber of the Flue Gas in the Coal-Fired Power Plant

2014 ◽  
Vol 962-965 ◽  
pp. 1476-1479
Author(s):  
Bing Cheng Liu ◽  
Wen Feng Dong ◽  
De Biao Zhou ◽  
Qian Liang ◽  
Qing Ling Li
Keyword(s):  
Flow Field ◽  
Flue Gas ◽  
Annular Flow ◽  
Theoretical Foundation ◽  
Co2 Absorption ◽  
Technological Parameters ◽  
Absorption Column ◽  
Gas Distributor ◽  
Column Wall ◽  
Fluent Software

In the article the flow field in the twin-tangential annular flow gas distributor was simulated based on the standard k-ε turbulent model with FLUENT software according to various distance L between sleeve and column wall and differing numbers of baffles, after comprehensively analyzing, got the best technological parameters with misdistribution factor and pressure drop. Based on the analysis of the flow field discipline of the twin-tangential annular flow gas distributor and the two-line vane gas distributor, and the systematic comparison of the performance of these two kinds of gas distributors in the flue gas CO2 absorption column, the research will provide the important theoretical foundation for the choosing and designing of the distributor of the flue gas CO2 absorber.

scholarly journals Photocatalytic Efficiency of TiO2-Biomass Loaded Mixture for Wastewater Treatment

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Devagi Kanakaraju ◽  
Soon Pang Wong
Keyword(s):  
Wastewater Treatment ◽  
Contact Time ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Wastewater Effluent ◽  
Photocatalytic Efficiency ◽  
Independent Variables ◽  
High Degree ◽  
Sago Bark ◽  
Mixture Sample

The objective of this study was to assess the efficiency of a novel TiO2/modified sago bark (TiO2/MSB) mixture for the degradation of sago wastewater effluent by employing response surface methodology (RSM) using chemical oxygen demand (COD) removal as the target parameter. The highest COD removal of 64.92% was obtained using TiO2/MSB mixture sample prepared by combining 0.2 g/L TiO2and 1 w/w% MSB. Given that the highest removal was produced using this mixture sample, further optimisation of sago wastewater treatment was conducted by varying the independent variables, namely, dosage and contact time. Under this optimum condition, 0.10 g of 0.2 g/L TiO2/1% MSB had successfully reduced 52.83% COD in 120 min. Surface morphology, functional groups, and elemental analysis supported observations of the ability of TiO2/MSB mixture to remove COD. Additionally, aeration had further improved COD removal by 11%. The regression value (R2>0.99) of the model indicated a high degree of correlation between the evaluated parameters. These results proved the feasibility of TiO2photocatalysis as an appealing alternative protocol for sago wastewater treatment and solid waste from the industry can be utilised for wastewater degradation.

scholarly journals Impact of Temperature on Biological Denitrification Process

1970 ◽  
Vol 7 (1) ◽  
pp. 121-126 ◽  
Author(s):  
Iswar Man Amatya ◽  
Bhagwan Ratna Kansakar ◽  
Vinod Tare ◽  
Liv Fiksdal
Keyword(s):  
Filtration Rate ◽  
Nitrate Nitrogen ◽  
Nitrate Removal ◽  
Biological Method ◽  
Biological Denitrification ◽  
Nitrite Nitrogen ◽  
Nitrogen Concentrations ◽  
In Series ◽  
Nitrate And Nitrite ◽  
Denitrification Process

Nitrate removal in groundwater was carried out by biological method of denitrification process. The denitrification and without denitrification were performed in two different sets of reactors. Each reactor consists of two columns connected in series packed with over burnt bricks as media. The filtration rate varied from 5.3 to 52.6 m/day for denitrification process. The ammonia, nitrate and nitrite nitrogen concentrations were measured at inlet, intermediate ports and outlet. The temperature varied from 10 to 30°C at 2°C intervals. The results demonstrated that high amount of nitrate nitrogen removed in groundwater at denitrification process. The nitrate nitrogen removed by denitrification varied from 3.50 to 39.08 gm/m3/h at influent concentration from 6.32 to 111.04 gm/m3/h. Denitrification was found more significant above 16°C.Key words: Over burnt brick, Denitrification, Filtration rate and TemperatureJournal of the Institute of Engineering, Vol. 7, No. 1, July, 2009 pp. 121-126doi: 10.3126/jie.v7i1.2070 

Experimental effect of medium ratio on removal efficiency of nitrate nitrogen in groundwater by zero-valent iron, activated carbon and zeolite

2019 ◽  
Vol 19 (6) ◽  
pp. 1636-1642
Author(s):  
Sizhi Cao ◽  
Peigui Liu ◽  
Mingchao Liu ◽  
Gang Wang ◽  
Zaili Li ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Nitrate Nitrogen ◽  
Nitrogen Concentration ◽  
Nitrate Removal ◽  
Ammonia Nitrogen ◽  
Coarse Sand ◽  
Zero Valent Iron ◽  
Nitrite Nitrogen ◽  
Rich Solution ◽  
Set Up

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.

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