Biofilter

Removal efficiencies (log.u)

E. coli

Fecal coliforms

Enterococci

Sand 1 – 2 mm

2.07^a

1.77^a

2.27^a

Sand 2 - 4 mm

0.85^a

0.98^ab

2.24^ab

Lateritic gravel 2 - 4 mm

1.54^a

0.71^ab

1.46^abcd

Lateritic gravel 4 - 6 mm

1.13^a

0.80^ab

0.96^cd

Granitic gravel 1 – 2 mm

2.38^a

1.59^a

1.91^abc

Granitic gravel 2 - 4 mm

1.40^a

1.03^ab

1.55^abc

Granitic gravel 4 - 6 mm

1.16^a

0.48^b

0.49^d