An orthogonal experiment was conducted to study the effects of chemical dissolution and biodegradation on the remediation efficiency for artificially contaminated soil by heavy metals Cu

Zn and Pb

as well as phenanthrene

naphthalene and pyrene. Humic acid (HA) was selected as eluent to strengthen the performance of microbial degra-dation of organic pollutants

which can effectively improve the degradation efficiency of degrading strain. Ac-tivated sludge was selected as degradation agent to strengthen the HA elution of heavy metals. The goal of this study was to reduce the polluted effect of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in soil and increase the remediation efficiency. Results showed that the optimal conditions for remediation were temperature 35℃

pH 6.5

inoculation amount of activated sludge 2.0% and humic acid 5mg/g. In this condition

the remediation efficiencies for phenanthrene

naphthalene and pyrene were 73.4%

80.5% and 68.2%

and for Cu2+

Zn>2+ and Pb3+

75.5%

64.2% and 71.7%

respectively. The addition of HA and activated sludge could significantly enhance the remediation of contaminated soil. It showed well the syner-gistic effect between chemical dissolution and biodegradation to remediate contaminated soil.