Onsite Dosing Bacteria Treatment Of Micro-polluted Source Water Under Conditions Of Liftng Water And Aeration

In recent years, with the development of industry and excessive use of agriculturalchemicals, the pollution of source water have become increasingly prominent, therefore,it is urgent to develop the new, efficient and safe pretreatment for source water. Whilebeing adopted to dispose micro-polluted water, in situ biological denitrification willmeet the problems, low temperature, oligotrophic and aerophile. This research is mainlyabout the denitrification characteristic of cold-tolerant bacteria have been isolated andthe denitrification efficiency on the in situ biological purification technology combinedwith lifTNg water and aeration technology. The main results are shown as below:（1）The research was about denitrification characteristics and growth curve ofcold-tolerant aerobic denitrifying bacteria F3, F4and YF3at5℃,10℃,15℃,respectively. The results showed that the denitrification characteristics and breedingwere influenced by temperature. The cell growth and the denitrification rate increasedwith temperature from5℃to15℃. And the denitrification process occured mostly inthe logarithmic growth phase, it was not obvious in other phases. Cell growth, NO₃^--Ndegradation rate, cell dry weight and TF concentration of strain F3at differenttemperature showed that it had a positive correlation among them. With the cellmetabolic and breeding, TF concentration and NO₃^--N degradation rate increased. Thehigher the temperature was, the faster the cell breeded, the greater of dehydrogenaseactivity and the degradation rate of NO₃^--N.（2）By source recombination, cold-tolerant and oligotrophic aerobic denitrifyingbacterial communities T1and T2were constructed. The denitrification characteristics ofthe two communities were investigated at different bacterium dosages. The results showed that community T1had different denitrifying capacities at different bacteriumdosages, denitrifying71%,91%and100%of NO₃^--N and56%,34%and52%of TN atthe bacterium dosages of0.1mg/L,0.2mg/L and1.0mg/L, respectively. Community T2denitrified at most66%and59.48%of NO₃^--N and TN at the bacterium dosage of0.2mg/L, respectively.（3）Under conditions of CODMn5.50mg/L and C/N ratio was2.44for sourcewater, oligotrophic aerobic denitrifying bacteria was dosed in pilot scale at thebacterium dosage of0.1mg/L. The result showed that, when dissolved oxygen was5.0⁸.0mg/L and water temperature was16²5℃, the test reached good effect, themaximum removal rate of NO₃^--N, TN and CODMnwas76.49%,77.72%and51.45%,respectively.（4）In order to explore the safety of biological agents, doing deactivatedexperiments by KMnO₄, NaClO and ClO₂. The results showed that biological agentswould not pose a threat to drinking water. Simulated reservoir conditions, the bacterianumber of different depths were in an order of magnitude; therefore, biological agentshad good dispersion properties. It provided theoretical basis for in situ biologicalpurification technology in large deep drinking water sources.