Comparison of chloride effect between A2O and SBR processes treating domestic wastewater

Abstract

A B S T R A C TThe synthetic wastewater as influent containing different chloride concentrations (150, 500, 1,000, 1,500, 2,500, and 5,000 mg/L) was fed to sequencing batch reactor (SBR) and anaerobic/anoxic/oxic (A 2 O) reactor to investigate the effect of influent chloride concentration on organics and nutrients removal. With the chloride concentration increasing from 150 to 5,000 mg/L, the chemical oxygen demand (COD) removal efficiency decreased linearly from 96.4 and 94.8% to 48.4 and 63.0% for SBR and A 2 O process, respectively. No significant effect of influent chloride concentration on nitrification process was observed in A 2 O reactor, while a sharp increase of effluent NH 3 -N concentration to 2.4 mg/L was detected in SBR process when the influent chloride concentration increased to 5,000 mg/L. In terms of phosphorus removal, the removal efficiency for total phosphorus (TP) started to decrease when 1,500 mg/L chloride was fed into the influent for both processes. However, more severe effect was observed in A 2 O reactor, without any phosphorus removal at 2,500 and 5,000 mg/L chloride concentrations. When the chloride concentration increased from 1,500 to 5,000 mg/L in SBR, the TP removal efficiency gradually decreased from 86.0 to 57.5%.

Carbon Dioxide-Mediated Desalination

“…To circumvent the use of heat and electrical energy in a desalination process, we envisaged that recognition of sodium and chloride ions will be critical for the success of desalination. Chloride ions in aqueous systems pose a significant environmental and agricultural threat because of the excessive use of the water softener. , Various chloride ion recognition and sequestration processes in aqueous solutions have been reported, mainly in the realm of supramolecular host–guest chemistry with sophisticated receptors, which require strenuous synthetic procedures. − Recently, polymeric variants of host–guest chemistry showed a promising performance in chloride ion capture, an approach that may lead to a whole new path for desalination processes. − …”

Removals of Organic and Nitrogen in Biogas Effluent by Aao System

“…AAO stands for anaerobicanoxic-oxic. AAO technology employs a continuous biological treatment process that employs a wide range of microorganisms for wastewater treatment, including anaerobic, anaerobic, and anaerobic microbiota [7]. Currently, AAO or AO technologies are widely used in highefficiency concentrated wastewater treatment systems in industrial zones; however, the process of operating A2O systems in wastewater treatment livestock has received little attention.…”

Carbon Dioxide-Mediated Desalination

“…To circumvent the use of heat and electrical energy in a desalination process, we envisaged that a recognition of sodium and chloride ions will be critical for the success of desalination. Chlorides in aqueous systems pose a significant environmental and agricultural threat, because of the excessive use of water softener that their presence implies 5,6 . Various chloride ion recognition and sequestration processes in aqueous solutions have been reported, mainly in the realm of supramolecular host-guest chemistry with sophisticated receptors, which require strenuous synthetic procedures [7][8][9][10][11][12] .…”