Oxidation ditch process using curved blade rotor as aerator

Oxidation ditch process is used to treat the municipal and domestic sewage. The untreated sewage generates fouling smell, harmful bacteria, etc. which is hazardous for public health and degrades the environment by librating noxious gases. This paper examines the use of curved blade aerator for oxidation ditch process. The rotor, which controls the aeration, is the main component of the aeration process. Therefore, the objective of this study is to find out the variations in overall oxygen transfer coefficient and aeration efficiency for different configurations of aerators by varying the parameters like speed of aerator, depth of immersion and blade tip angles so as to yield higher values of overall oxygen transfer coefficient and aeration efficiency. Four aerators of different configuration were developed and fabricated in the laboratory and were tested for above mentioned parameters. A mathematical model is developed for predicting the values of k_La and aeration efficiency which has R2 values of 0.97 and 0.99 for experimentally determined and calculated values. In laboratory studies, the optimum value of overall oxygen transfer coefficient and aeration efficiency were observed to be 10.33/hand 2.269 kg O₂/kWh for aerator speed of 48 rpm, 5.5 cm depth of immersion and 47° blade tip angle for curved blade aerator.