TABLE 1.

Description of biofilm sampling sites and major water quality parameters^a

Site	Origin	Raw water source	Description of site and water treatment process	Biofilm collector location	Water residence time (h)	Avg temp (°C)	Residual chlorine (mg/liter)	AOC (μg/liter)	BDOC (mg/liter)
A1	FR	Pound	O3, mineralization, clarification, SF, O3, GAC, ClO2	Net	23	21.0	0	ND	1.0
A2	FR	Pound	O3, mineralization, clarification, SF, O3, GAC, ClO2	Net	68	18.6	0	ND	1.3
A3	FR	Pound	O3, mineralization, clarification, SF, O3, GAC, ClO2	Net	77	ND	0.01	ND	2.2
D1	FR	Reservoir	NaOCl, MnO4, remineralization, clarification, SF, PO4 injection, O3, NaOCl	Net	100	13.5	0.1	ND	0.2
D2	FR	Reservoir	NaOCl, MnO4, remineralization, clarification, SF, PO4 injection, O3, NaOCl	Net	106	13.5	0.2	ND	0.2
D3	FR	Reservoir	NaOCl, MnO4, remineralization, clarification, SF, PO4 injection, O3, NaOCl	Net	130	13.0	0.1	ND	0.1
M1	FR	Pond	Mineralization, flotation, SF, O3, mineralization, Cl2	Net	36	15.0	0.01	ND	0.6
M2	FR	Pond	Mineralization, flotation, SF, O3, mineralization, Cl2	Net	56	15.0	0.01	ND	0.6
T1	FR	River	Mineralization, flotation, O3, SF, O3, ClO2	Net	2	17.0	0.03	ND	0.14
T2	FR	River	Mineralization, flotation, O3, SF, O3, ClO2	Net	6	17.0	<0.1	ND	0.23
R1	LV	River	O3, chemical coagulation, clarification, SF, O3, BAC, Cl2	Plant before Cl2	0	2.8	0.2	205	ND
B1	LV	Lake	Artificially recharged groundwater, Cl2	Plant before Cl2	0	6.7	<0.1	209	ND
B2	LV	Lake	Artificially recharged groundwater, Cl2	Net	ND	5.4	<0.1	236	ND
B3	LV	Lake	At bottled water production plant using tap water treated with SF, softening, NaOCl, GAC	After addition treatment	ND	9.2	<0.1	263	ND
C1	LV	Groundwater	Small local water supply system using iron removal and softening	Net	ND	11.5	<0.1	117	ND

^aAbbreviations: ND, not determined; FR, France; LV, Latvia; SF, sand filtration; BAC, biologically active carbon; GAC, granular activated carbon.