Biological denitrification of reverse osmosis brine concentrates: I. Batch reactor and chemostat studies

Abstract

A major technological concern with reverse osmosis in water purification, wastewater treatment, and water reclamation or recycling is the production of brine concentrates high in ammonia or nitrogen. This project addresses biological denitrification of reverse osmosis brine concentrates in a bioactive fluidized bed adsorber reactor (FBAR), accomplished in four stages. The first three stages are described in this paper, while the final stage is addressed in the companion paper (Ersever et al. 2007). The first stage optimized an FBAR to produce nitrified brine for subsequent denitrification studies. The second stage employed batch reactors to evaluate denitrification parameters such as temperature, pH, total dissolved solids, and carbon-to-nitrogen ratio. The specific denitrification rate was maximum at a temperature of 35 °C, pH of 8.0, and carbon-to-nitrogen ratio of 1.8. The third stage involved chemostats to determine Monod parameters under nitrate-, nitrite-, and carbon-limiting conditions. A biokinetic model was employed to simulate chemostat dynamics and to estimate the biological parameters. The final stage entailed FBAR denitrification experiments under different hydraulic retention times, nitrate concentrations, and packing media; simultaneous denitrification and sulfate reduction were addressed. A second FBAR used in series with the first achieved an overall sulfate reduction of 99%, and a biofilter effectively removed the hydrogen sulfide generated.

Treatment of organics in reverse osmosis concentrate from a municipal wastewater reclamation plant: Feasibility test of advanced oxidation processes with/without pretreatment

“…In the past several years, several simple AOPs, such as photocatalytic oxidation (PCO), ozonation (O 3 ), sonolysis (US) and electrolytic oxidation, have been investigated for organics removal from the RO concentrates [9][10][11][12][13][14][15][16][17]. However, in most cases, these AOPs could only mineralize small fractions of the organics.…”

Biological removal of nitrate by an oil reservoir culture capable of autotrophic and heterotrophic activities: Kinetic evaluation and modeling of heterotrophic process

“…Denitrification process which also serves as a critical step in removal of ammonia from domestic wastewaters [1] relies on the activity of denitrifying bacteria which use nitrate or nitrite as an electron acceptor during the oxidation of organic or inorganic compounds for the purpose of energy generation. Denitrification occurs through a number of sequential reactions in which nitrate is reduced to nitrite, and subsequently to nitrogen oxides and nitrogen gas, as described below [7]: …”

“…Autotrophic denitrifying bacteria use sulphide, sulphur, or hydrogen as the electron donor, while heterotrophic denitrifiers utilize various organic compounds such as methanol, ethanol, formate, acetate, and lactate as electron donor [3,7,8]. dilution rate (h −1 ) E -NO 3 activation energy, nitrate reduction (kJ mol −1 ) E -NO 2 activation energy, nitrite reduction (kJ mol −1 ) K S-NO 3 saturation constant, nitrate reduction (mM NO 3 ) K S-NO 2 saturation constant, nitrite reduction (mM NO 2 ) K d-NO 3 decay coefficient, nitrate reduction (h −1 ) K d-NO 2 decay coefficient, nitrite reduction (h −1 ) S 0-Ace initial acetate concentration (mM) S Ace acetate concentration (mM) S 0-NO 3 initial nitrate concentration (mM) S NO 3 nitrate concentration (mM) S 0-NO 2 initial nitrite concentration (mM)…”

“…heterotrophic denitrification have focused on various aspects of this process including type of the electron donor [2,[9][10][11], kinetic modeling [3,7,12,13], bioreactor design [4,6,[14][15][16][17], and simultaneous nitrification and denitrification (SND) process [1,18,19]. Autotrophic denitrification has attracted much attention in recent years due to its beneficial applications in desulphurization of sour gases, biogas, and sulphide laden waters, as well as its critical role in the in situ removal of H 2 S from the oil reservoirs subjected to water flooding [8].…”

Removal of nitrates from high-salinity wastewaters from desulphurization process with denitrifying bacteria encapsulated in Lentikats Biocatalyst

“…Common low-cost biological methods utilizing activated sludge often fail when applied to industrial wastewaters and special pretreatment is often necessary to remove biological inhibitors (Beliavski et al 2010;Cyplik et al 2007;Ersever et al 2007; Lefebvre and Moletta 2006;McAdam and Judd 2008;McAdam et al 2010;Wisniewski et al 2002). Salinities higher than *1 % cause inhibition of nitrification and denitrification of the activated sludge (Dincer and Kargi 1999;Lefebvre and Moletta 2006;Mariangel et al 2008).…”