zichun yan, Rong Zeng, Li Shen

The experiments prepared bio-fillers using corn cobs as raw materials. Heat modification was identified as the optimal method by comparing the physical and chemical properties (roughness, porosity, water immersion stability, and compressive strength) of unmodified, acid modified, alkali modified, and heat modified corn cobs. Subsequently, the heat modification conditions were optimized, and the heat-treated corn cob (HCC) was utilized in a laboratory-scale A/O bio-contact oxidation device to observe the removal efficiency of pollutants while also assessing the lifespan of HCC. The results demonstrated that the roughness, water immersion stability, and porosity of HCC were superior to those of corn cobs treated with the other three methods. The compressive strength of HCC prepared under optimal heat modification conditions (260 ± 5°C for 50 minutes) ranged from 0.92 to 0.99 MPa, with porosity reaching up to 52.03%. Under the conditions of an influent flow rate of 200 L/d, a reflux ratio of 1, an aeration volume of 0.2 m3/h, and a sludge retention time of 15 days, the average removal rates of COD, TN, NH4+-N, and TP from domestic sewage were 90.1%, 72.76%, 89.57%, and 55.50%, respectively. The effluent could be used for agricultural irrigation. The lifespan assessment indicated that HCC fillers could be used for up to 12 months. In summary, corn cobs served as effective fillers for the treatment of rural sewage.