Simultaneous removal of nitrogen and phosphorus from wastewater by means of FeS-based autotrophic denitrification

摘要

The efficacy of iron(II) sulfide (FeS)-based autotrophic denitrification in simultaneous nitrogen and phosphorus removal from wastewater was studied with batch experiments. It was efficient at a wide pH range of 5-9, and temperature range of 10-40 WC. The concentrations of NH~(4+)-N, Mg~(2+) and HCO_3 - in the wastewater should be kept over 7.8, 0.24 and 30 mg L~(-1) for efficient nitrate (NO_3 --N) reduction, respectively. The NO_3 --N removal rate increased from 0 to 82 mg L~(-1) d~(-1) and then leveled off when the NO_3 --N concentration increased from 0 to 415 mg L~(-1) and then to 700 mg L~(-1) respectively. The NO_3 --N removal rate quickly increased, leveled off, and then sharply decreased when the PO_4 ~(3-)-P concentration increased from 0 to 0.1 mg L~(-1), then to 114.0 mg L~(-1), and further to 683.8 mg L~(-1), respectively. The PO_4 ~(3-)-P removal was over 98% when the PO_4 ~(3-)-P concentration ranged 0-683.3 mg L~(-1). During treatment of the secondary effluent of a local municipal wastewater treatment plant containing NO_3 --N of 14.9 mg L~(-1) and total phosphorus (TP) of 3.9 mg L~(-1), NO_3 --N was reduced to 1.1 mg L~(-1) and TP was completely removed.