Abstract:

Experiments were conducted to investigate influences of N, S, P and humidity on microbial activity in landfill leachate polluted site. The results indicated that maximum microbial activity in soil and fine sand was up to 0.685 and 0.588 in the 7th day and the 14th day while N and P added, respectively; organic substrate decreased 10.97% and 22.1%, and its average degradation rate was 0.405 and 0.190 mg/(kg·d), respectively. Organic substrate decreased 10.3% and 28.9% for NO^-₃ addition and 8.87% and 28.4% for SO^2-₄ addition in soil and fine sand, respectively. In addition, the maximum microbial activity was 0.259 and 0.266 in soil which humidity was 50% and 60%, respectively, and the average degradation rate of organic substrate was 0.195 and 0.305 mg/(kg·d), respectively. Therefore, N, S, P and humidity had significant effects on subsurface microbial activity.

Key words: landfill leachate, microbial activity, pollution site, electron acceptors, nutrients