Table 4.

Effect of contact time for reduction of total and fecal coliforms from secondary treated effluent using nano-Ag-oxide.

Time	Control		Nano-Ag-oxide
	Total coliforms (MPN-index/100 mL)	Fecal coliforms (MPN-index/100 mL)	Total coliforms		Fecal coliforms
			Conc. (MPN-index/100 mL)	% of removal	Conc. (MPN-index/100 mL)	% of removal
Zero time	4.1 × 103	1.8 × 102	4.1 × 103	0.0	1.8 × 102	0.0
2 min	4.6 × 103	1.7 × 102	1.1 × 103	73.2	1.4 × 102	22.2
5 min	5.1 × 103	2.1 × 102	7.5 × 102	81.7	1.1 × 102	38.9
10 min	5.7 × 103	2.6 × 102	1.8 × 10	99.6	1.5 × 10	91.7
15 min	6.2 × 103	3.1 × 102	1.5 × 10	99.6	1.0 × 10	94.4
20 min	6.4 × 103	4.1 × 102	1.1 × 10	99.7	5.3	97.1
30 min	6.8 × 103	5.8 × 102	1.0 × 10	99.8	5	97.2