Table 4.

Comparing log₁₀ reduction averages of viruses, bacteria, and protozoa in two foam-based biofilter units after biofilm development

Sampling site	P22 N = 10*		MS2 N = 9		R. terrigena N = 10		C. parvum N = 4
	Sleeve	Disk	Sleeve	Disk	Sleeve	Disk	Sleeve	Disk
INF-FLOC	1.50 ± 0.37†	1.60 ± 0.46	1.59 ± 1.09	1.78 ± 1.30	1.14 ± 0.36	1.14 ± 0.81∥	0.71 ± 0.32	0.83 ± 0.04
FLOC-BSN		2.22 ± 0.43		2.23 ± 0.69		2.74 ± 1.30		3.71 ± 0.51
BSN-PRECHL‡		2.40 ± 0.04		0.54 ± 0.50		3.98 ± 1.49		1.98 ± 0.89
PRECHL-EFF	> 0.16 ± 0.31	> 0.01 ± 0.00	0.03 ± 0.10	0.00 ± 0.00	> 1.72 ± 1.01	> 0.73 ± 0.58	> 0.00 ± 0.00§	> 0.00 ± 0.03§
FLOC-PRECHL	4.50 ± 0.42	4.38 ± 1.00	2.92 ± 0.51	2.77 ± 0.84	5.82 ± 1.09	6.72 ± 2.11	5.51 ± 0.85	5.60 ± 0.88§
INF-PRECHL	6.00 ± 0.49	6.23 ± 0.46	4.51 ± 1.25	4.55 ± 1.04	6.96 ± 1.34	7.77 ± 0.87	6.23 ± 0.70§	6.52 ± 0.71§
INF-EFF (Total)	≥ 6.16 ± 0.64	≥ 6.24 ± 0.46	≥ 4.55 ± 1.26	≥ 4.55 ± 1.04	≥ 8.47 ± 0.55	≥ 8.36 ± 0.69∥	≥ 6.46 ± 0.64§	≥ 6.45 ± 0.86§

^*N = Number of events used in calculation, unless otherwise noted.

^†± = Standard deviation.

^‡After foam disc before carbon, this could only be evaluated for the disk configuration.

^§N = 3 for the evaluation of some Cryptosporidium reductions.

^∥9 events used to calculate INF-FLOC and INF-EFF reductions.