The Cultivation And Temperature Coefficient Test Of PAO_HT

With the wastewater riched in the elements nitrogen and phosphorus being discharged into the water body,eutrophication has become increasingly severe.Therefore the removal of nitrogen and phosphorus in eutrophic water has becoming the focus research in wastewater treatment.Enhanced biological phosphorus removal?EBPR?is widely used as an economical and effective method for the biological phosphorus removal of wastewater.However,it is often deteriorate or even collapse.And this is largely due to the competitive to the limited substrate between polyphosphate accumulating organisms?PAOs?and glycogen accumulating organisms?GAOs?.At present,the effect of temperature on the PAO activity and its substrate competition with GAO has not come to a conclusion.Therefore,it is necessary to further study the competition between PAO and GAO under different temperature conditions,especially at high temperature.In order to guarantee the stable operation of the EBPR in the higher temperature.To better understand the activity of high temperature phosphate accumulating organisms(PAO_HT)and their competitive ability to the substrate under high temperature in EBPR process,the rates of anaerobic phosphorus release,aerobic phosphorus uptake and acetate uptake of PAO_HT with temperature among 15? to30? were examined.And the potential PAO_HT and GAO populations were first screened via fluorescent in situ hybridization?FISH?.Results are as follows.?1?The EBPR performance kept in 30? for 270 days,the phosphorus removal efficiency reached 99%.The phosphorus release and phosphorus uptake rate in sludge were 239.46 and 79.90mgP×?gVSS×h?-1,and ?P/?HAc arrived 0.628.The PAO_HT accounted for the proportion of total bacteria up to 86±3%,while the proportion ofGAO only about 4%.The reactor runs efficiency and stably.There has been appeared the PAO_HTthat could adapt to high temperature.?2?The results showed an increase in temperature from 15? to 30? causes a significant increase of the activity of PAO_HT and their competitive ability to the substrate.And when the temperature is 15,20,23,25,27,30?,the maximum anaerobic phosphorus release rate were 76.50,95.86,150.69 171.74,239.46,150.78,mgP ×?gVSS×h?-1,the maximum aerobic phosphorus uptake rate were 27.36,44.72,49.61,51.52,61.73,79.90 mgP×?gVSS×h?-1,the maximum uptake rate of acetate were176.70,233.14,241.59,247.22,313.37,357.47 mgHAc ×?gVSS × h?-1.When the temperature was as higher as 30?,the acetate uptake of PAO_HT was higher than previous research,which is about 0.269 C-mmol ×?C-mmol×h?-1.?3?A simplified Arrhenius equation is used to describe the effect of temperature on the rates of anaerobic phosphorus release,aerobic phosphorus uptake and acetate uptake,and the temperature coefficients are 1.08,1.07 and 1.05,respectively.