Table 4.

Comparison of biological denitrification capacity among different approaches.

Denitrification Approach	Packing Material/Electron Donors	System Description	Maximum Nitrate Removal Efficiency (%)	Maximum Nitrate Denitrification Rate (g m−3·d−1)	References
HSHAD	Sulfur/H. verticillata/gravel/wetland and paddy soil	Free water surface constructed wetland mesocosm	100	7.0	This study
HAD	Sulfur/methanol/anaerobic sludge/sulfur autotrophic denitrificans	Sulfur packed bed reactor	89	5050.0 b	[60]
HAD	Sulfur/methanol/aerobic and anaerobic sludge/	Sulfur particle master culture reactor	>97 b	1920.0 b	[28]
HAD	Sulfur/acetate/anaerobic sludge/sulfur autotrophic denitrificans	Sulfur particle master culture reactor	100 b	98.9 b	[73]
HAD	Pine bark/spongy iron/sand/gravel/heterotrophic and autotrophic denitrificans	Double-layer permeable reactive barrier	99 b	9.5 b	[21]
HAD	Sulfide/sulfide-degrading bacteria (Pseudomonas sp. C27)/acetate	Expanded granular sludge bed	100 b	NA a	[75]
HAD	Sulfur/heterotrophic and autotrophic denitrificans/methanol	Fluidized bed reactor	−100 b	1440.0 b	[17]
HAD	Cotton/zero valent iron (R4)/bacteria inoculation	Double layer column reactor	−100 b	275.0 b	[72]
HAD	Sulfide/acetate	Anaerobic continuous stirred tank reactor	100	−13.8 b	[74]
HAD	Sulfur/limestone/methanol	Lab-scale packed-bed bioreactor	100 b	5.0 b	[19]
HAD	Methanol/anaerobic sludge	Intensified biofilm-electrode reactor	97	−146.0	[22]
HAD	Seed sludge/sulfur/woodchips/ /Thiobacillus bacteria inoculation	Serum bottle reactor	100 b	−18.0 b	[31]
HAD	Thiobacillus bacteria inoculation/sulfur/limestone	Pilot-scale horizontal flow CW	−67 b	NA a	[20]
HAD	Ethanol/sulfur sesquioxide/anaerobic sludge	Serum bottle reactor	100 b	NA a	[76]

^a No data available. ^b Estimated or calculated based on the data of the references.