Fluid bed biological nitrification and denitrification in high salinity wastewater

Abstract

Wastewater from wet lime(stone)-gypsum flue gas desulphurisation (FGD) processes in coal-fired power plants contains nitrate. Where case selective catalytic reduction (SCR) of NOx is applied the wastewater can also contain ammonia. For the removal of both nitrate and ammonia, biological processes are an attractive option. A bottle-neck for application of biological processes might be the high chloride concentration and relatively high temperature of the wastewater. Therefore research work was performed in fluid-bed reactors at pilot-plant scale for both biological nitrification and denitrification. Biological nitrification was studied up to 34 gCl−/l and nitrite was the main product formed. Biological denitrification was effective up to at least 45 gCl−/l. Both nitrate and nitrite were removed effectively.

Nitrification in fixed-bed reactors treating saline wastewater

“…A higher sensitivity of AOB to high salt concentrations of pure cultures was reported (Moussa et al 2006). Controverse results were found by Kawasaki et al (1996) or Vredenbregt et al (1997).…”

Partial nitrification and denitrification in a sequencing batch reactor treating high-salinity wastewater

“…Although researchers have studied nitrogen removal using PND process [5,24], a limited number of studies have reported on the PND process with high salinity [25]. For this reason, the main objective of this study was to investigate the salt effects on PND process and nitrogen removal efficiency in a SBR at a constant operational condition.…”

Osmotic stress on nitrification in an airlift bioreactor

“…[6,7] These ions tend to exert high osmotic pressure (OP) on nitrifying microorganisms. Most of the microbial populations are unable to cope with environments of very high osmotic pressure and either die or become plasmolyzed and dormant under such conditions [5].…”

“…The effect of salts in wastewater on nitrification has been investigated extensively [7][8][9][10][11]. However, presently no report concerning the effect of osmotic pressure on the biological wastewater treatment is available.…”