Keywords: activated sludge microbes, DNA sequence diversity, random amplified polymorphism DNA, RAPD, zinc ion, sewage treatment
Analysis of the effect of zinc ions on activated sludge microbes by random amplified polymorphism DNA (RAPD)
The effect of zinc ions on activated sludge microbes was investigated. Zinc ions inhibit the degradation and transformation of substances, and acclimation has little effect on the inhibition of ammonia and nitrite transformation. The change of diversity and similarity of the bacterial community acclimated by zinc were analysed by random amplified polymorphism DNA (RAPD). The results showed that DNA sequence diversity was different during different stages of acclimation. The microbial diversity of the zinc loading unit was lower than that of the control unit. There were wide differences in diversity, richness, evenness and similarity between the beginning and the end of acclimation, although the chemical oxygen demand removal rate reached the same value at the end. The RAPD fingerprint revealed that some bacteria disappeared and some zinc-tolerant species survived. The results were instructive for us to control the running of biological treatment systems and to apply corresponding recovery techniques in the period after damage.