Reduction in chlorine requirements by control of nitrification in an oxygen activated sludge process

Matson, Jack V.; Andrews, John; Garrett, M.T.

doi:10.1016/0043-1354(82)90123-3

Cited by 4 publications

(17 citation statements)

References 1 publication

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“…In the second period, 24 days after the starting day of the reactors operation, both the sand and GAC reactors responded with more NH 4 + -N oxidation capacity as shown in fig. 2.…”

Section: Resultsmentioning

confidence: 99%

“…The capacity was calculated by eqn. reactors had shown no improvement in the NH 4 + -N oxidation capacity. During this period, the nitrifiers' attachment and detachment are the same and even though the growth was noticed there was no improvement in the NH 4 + -N oxidation capacity.…”

Section: Resultsmentioning

confidence: 99%

“…Samples from the inlet and outlet stream of the reactors were collected daily for analysis of NH 4 + -N and NO 2 --N; NO 3 --N, oxygen and pH were measured sometimes. Immediately before collecting the samples the temperature was measured with a mercury thermometer and the flow rate to each reactor was measured volumetrically.…”

Section: Measurement and Analytical Methodsmentioning

confidence: 99%

“…(4) for the oxidation of NH 4 + -N to NO 2 -is 0.146. The yield reported [5] for the oxidation of NH 4 + -N by Nitrosomonas bacteria based on experimental mixed culture is between 0.04 and 0.3 and that based on pure culture is 0.29. Other reported [7][8][9] …”

Section: Nitrificationmentioning

confidence: 99%

“…Due to the ammonia chlorine demand [3], one mole of ammonia requires 1.5 moles of chlorine; this on a weight basis is 7.5 parts of chlorine to 1 part of NH 3 -N. For this reason ammonia exerts a high chlorine demand that must be satisfied before chlorine is available for disinfection and some residual remains in the water. High chlorine dosages may produce trihalomethanes and add chlorine ions to the system [4].…”

Section: Introductionmentioning

confidence: 99%

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Biological ammonia removal from drinking water in fluidized bed reactors

Aboabboud¹,

Ibrahim²,

Awad³

2008

WIT Transactions on Ecology and the Environment

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Ground water is the most reliable source of drinking water and frequently contains ammonia as a pollutant in concentrations up to 3mg/L. The recommended maximum concentration level (MCL) according to the World Health Organization (WHO) is 0.5 mg/L. Concentrations in excess of this in drinking water can be oxidized to toxic nitrite, support the growth of bacteria, (Nitrosomonas and Nitrobacter), and create taste and other problems in treatment plants and the distribution network. High ammonia concentrations also create high chlorine demand during disinfection that consequently produces trihalomethanes and organochlorines suspected to be carcinogenic. In this work the biological oxidation of ammonia to nitrite and consequently to nitrate by nitrifying bacteria, Nitrosomonas and Nitrobacter was studied in two fluidized bed reactors, each having one type of biofilm supporting material: sand and granular activated carbon (GAC). The aim was mainly to investigate the possibility of ammonia oxidation to nitrate when the ammonia concentration is low, and how the support materials influence the starting up period and the rate of ammonia oxidation capacity of the nitrification process. In this study the main equipment used were two reactors and an aerator, which were made of Plexiglas tubes. Synthetic water containing ammonia nitrogen (1-3 mg/L) was fed to the reactors in fluidization mode. Both GAC and sand reactors gave ammonianitrogen (NH 4 + -N) oxidation capacity up to 2.5 kg/m 3 of nitrogen per day. The type of the support material that was found to be successful in nitrification is GAC. Nitrification in the sand reactor proceeded at a very slow rate compared to the GAC reactor. The GAC reactor had a higher oxidation rate and steeper curve compared to the sand reactor and reached maximum nitrite production earlier than the sand reactor.

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“…In the second period, 24 days after the starting day of the reactors operation, both the sand and GAC reactors responded with more NH 4 + -N oxidation capacity as shown in fig. 2.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Measurement and Analytical Methodsmentioning

confidence: 99%

Section: Nitrificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Biological ammonia removal from drinking water in fluidized bed reactors

Aboabboud¹,

Ibrahim²,

Awad³

2008

WIT Transactions on Ecology and the Environment

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Modeling drinking water chlorination at the breakpoint: I. Derivation of breakpoint reactions

Driss¹,

Bouhelassa²

2014

Desalination and Water Treatment

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A B S T R A C TFrom a bibliographic synthesis on the reactions that can occur during breakpoint chlorination. We carry out the stability study of produced entities under the applied conditions in the potable water production, where the pH range 6.5-8.5, and the initial weight ratio Cl/N including in 10/1-15/1 at ambient temperature. The choice of dominant species and reactions that have been taken into account must be based on data of the thermodynamics and the kinetics governed by pH and temperature. Through this selection appears a large disagreement in results of researches between the rate expressions of the kinetics and observed and even with the empirical results, especially for reaction the monochloramine formation and for equilibrium the formation-hydrolysis of trichloramine. Then, the nature of identified intermediate and the observed rate of its formation reaction were not agree in different published works, as well the possibility of destruction of the free chlorine residual by this intermediate is not confirmed yet. Through this study, we obtain a representative selected group of reactions during breakpoint chlorination process, this identified group of reactions is compared with other models of breakpoint reactions proposed in the literature, where some differences appear.

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Modelling drinking water chlorination at the Breakpoint: II. Calculation of the chlorine and chloramine concentrations along municipal pipe

Driss

Bouhelassa

Boudabous

2014

Desalination and Water Treatment

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A B S T R A C TThis study is focused on the determination of added chlorine dose in low ammoniacal concentration contained in distribution pipe of drinking water. The chlorine concentration in disinfected water varies between events of lack and excess that must be regularly controlled. The chlorine transport from the inlet to the outlet of pipe is carried out in turbulent flow where the phenomena of diffusion and convection are in charge to convey chlorine and chloramines formed along the polyvinylchloride pipe. The chlorine decay is principally due to ammonia consumption in the water bulk. The chlorine demand serves to generate inorganic chloramines and the formation of an uncertain intermediate, which helps to destruct them, and the reactions series of formation-destruction are referring to Breakpoint chlorination. The set of presented reactions at Breakpoint chlorination are not clear and the observed rate constants are not similar in the researchers found in the literature. Then, their choices are not easy because they cause large differences between the experimental profiles of disinfectants concentrations taken from literature and the predicted profiles of disinfectant concentrations investigated in the present paper. The set of differential equations are resolved simultaneously by the method of finite differences. Therefore the concentrations of free residual chlorine, ammonia, monochloramine, dichloramine, trichloramine, nitrogen hydroxide and total chlorine are calculated at different points constituted the municipal pipe.

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Reduction in chlorine requirements by control of nitrification in an oxygen activated sludge process

Cited by 4 publications

References 1 publication

Biological ammonia removal from drinking water in fluidized bed reactors

Biological ammonia removal from drinking water in fluidized bed reactors

Modeling drinking water chlorination at the breakpoint: I. Derivation of breakpoint reactions

Modelling drinking water chlorination at the Breakpoint: II. Calculation of the chlorine and chloramine concentrations along municipal pipe

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