Study On Oxygen Transfer Efficiency Of Aeration Basin With Carrier

As an important part of aerobic biological wastewater treatment process, aeration accounts for45%to75%of the total power consumption cost. The main role of aeration is to provide sufficient dissolved oxygen for reactor to meet the microbial and biochemical need, and to maintain the mixing of reactor residues, microbes, dissolved oxygen. The amount of dissolved oxygen affects the aerobic microbial’s ability to degrade organic matter. Only if the dissolved oxygen is adequate, aerobic microorganisms can degradate the wastewater organic matter efficiently. Therefore, The oxygen transfer effect in aeration pool directly impacts on the rate of microbial degradation of organic matter in the reactor and sewage treatment effect and enhanced aeration oxygen transfer effect is of great significance for reducing aeration power consumption and improve water treatment efficiency.Based on oxygen transfer efficiency (E02) theory, and by using1m×0.5m×2m plexiglass reactor, This paper studied on the influence of different factors on the efficiency of oxygen transfer in new aeration basin(grid bio-carrier reactor), and discussed the experimental results. The impact factors included aeration rate, temperature, carrier style and size, aeration methods and etc. By varying the experimental conditions and comparing different experiments, this paper got the system oxygen transfer performance under different experimental conditions. The results are as followed.(1) Oxygen transfer coefficient increased with increasing aeration intensity, but rising rates were different from each other. The oxygen transfer coefficient and oxygen transfer efficiency of grid bio-carrier reactor showed non-linear increasing trend with aeration intensity increasing. When aeration rate was3.5m3/h, the oxygen transfer rate and the oxygenated power-efficiency respectively reached to5.25%and3.22kgO2/(kW-h), which both were1.07times of the vertical pool and suspension ball pool,1.22times of the carrier-free pool. Therefore it was helpful for the oxygen transfer in aeration basin with grid carrier.(2) Oxygen overall transfer coefficient in new style aeration basin increased with the temperature. As lower temperature leading to higher saturation concentration, it was helpful for the oxygen transfer by appropriatly lower the water temperature.(3) The eyelet size of grid carrier had great influence on oxygen overall mass transfer coefficient (Kla(20)), when aeration rate was3.5m3/h, the ration of the maximum oxygen transfer efficiency (Eo2max) of the I#reactor (non-carrier), the2#reactor (eyelet size of0.5×0.5cm) and the3#reactor (eyelet size of l×lcm) was1.21:1:1.06. So it was helpful for improving oxygen transfer efficiency by small size of grid carrier in a certain range.(4) The types of aeration had great influence on oxygen transfer efficiency. When the aeration rate was low, the KLa (20) and E02in the tubular micro-porous aeration pool was higher than that in the tubular perforated aeration pool, and as the aeration rate increased to4.5m3/h, KLa(20) and E02increasing rate of the tubular perforated aeration pool got to the maximum value. When the aeration rate was4.0m3/h, the KLa(20) and E02of the two aeration types were almost in the same level. When the aeration rate was higher than4.5m3/h, E02of the tubular micro-porous aeration pool descended faster. Contact oxidation tank equipped with micro-pore aeration pipes could be used for treating domestic wastewater, and be used for treating high concentration organic wastewater equipped with perforated aeration pipes.