Table 1: Characteristics of landfill leachate with different periods.

Leachate typeEarlyMedium-termOld

Landfill useful life (years)<55–10>10
pH (−)6.5–7.5 (7.0)7.0–8.0 (7.5)7.5–8.5 (8)
COD (g/L)10–30 (15)3–10 (5)<3 (2)
BOD/COD (−)0.5–0.7 (0.6)0.3–0.5 (0.4)<0.3 (0.2)
NH4+-N (mg/L)500–1000 (700)800–2000 (1000)1000–3000 (2000)
COD/NH4+-N5–10 (6)3-4 (3)<3 (1.5)

The values in parentheses are typical values.