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Table 5

Median and maximum NH₄-N effluent concentrations in mg/L of VF wetlands loaded every 6 hours with 0.5 holes in distribution pipes per m² (maximum concentrations in brackets)

Filter	OLR	5 °C		10 °C		15 °C		20 °C
material	g COD m⁻².d⁻¹	Median	(Max)	Median	(Max)	Median	(Max)	Median	(Max)
0.06–4 mm	20	4.0	(4.0)	1.1	(1.1)	0.4	(0.4)	0.1	(0.1)
	40^a	3.1	(3.6)	1.3	(1.4)	0.4	(0.4)	0.1	(0.1)
	80^a	1.4	(9.3)	0.2	(5.6)	0.1	(4.5)	0.1	(4.7)
1–4 mm	20	29.8	(29.9)	8.0	(8.1)	2.9	(3.0)	0.9	(1.0)
	40	28.1	(30.3)	7.1	(8.9)	2.9	(3.2)	1.1	(2.1)
	80	34.9	(43.3)	15.6	(30.3)	14.1	(28.7)	16.7	(28.8)
4–8 mm^b	20	30.5	(30.6)	7.5	(7.5)	2.8	(2.9)	1.0	(1.0)
	40	27.0	(29.0)	6.1	(8.3)	2.7	(3.0)	1.0	(1.6)
	80	34.8	(41.7)	13.9	(27.8)	13.9	(26.3)	14.8	(26.2)

Filter	OLR	5 °C		10 °C		15 °C		20 °C
material	g COD m⁻².d⁻¹	Median	(Max)	Median	(Max)	Median	(Max)	Median	(Max)
0.06–4 mm	20	4.0	(4.0)	1.1	(1.1)	0.4	(0.4)	0.1	(0.1)
	40^a	3.1	(3.6)	1.3	(1.4)	0.4	(0.4)	0.1	(0.1)
	80^a	1.4	(9.3)	0.2	(5.6)	0.1	(4.5)	0.1	(4.7)
1–4 mm	20	29.8	(29.9)	8.0	(8.1)	2.9	(3.0)	0.9	(1.0)
	40	28.1	(30.3)	7.1	(8.9)	2.9	(3.2)	1.1	(2.1)
	80	34.9	(43.3)	15.6	(30.3)	14.1	(28.7)	16.7	(28.8)
4–8 mm^b	20	30.5	(30.6)	7.5	(7.5)	2.8	(2.9)	1.0	(1.0)
	40	27.0	(29.0)	6.1	(8.3)	2.7	(3.0)	1.0	(1.6)
	80	34.8	(41.7)	13.9	(27.8)	13.9	(26.3)	14.8	(26.2)

^aOLR >20 g COD m⁻².d⁻¹ is not experimentally verified in temperate climates.

^bResults for NH₄-N of the 4–8 mm main layer could not be fitted well (see Pucher & Langergraber 2018).

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