曝气时间对美人蕉生态浮床去除水体中营养盐的影响

为有效去除水体中的营养盐,以美人蕉生态浮床为研究对象,将曝气时间设置为0(对照)、4、8、12 h/d,曝气量均为2.4 m3/(m2·d),研究曝气时间对植物生态浮床去除水体中营养盐的影响,在培养的0、3、5、7、18、28 d对美人蕉株高进行测量,同时监测水体中ρ(DO)、ρ(TN)、ρ(TP)、ρ(COD_Cr)、ρ(NH₃-N)、ρ(NO₃--N),试验结束后对美人蕉根际细菌总数进行测定. 结果表明:①与对照组相比,曝气4和8 h/d情况下ρ(DO)及TN、TP、NH₃-N、NO₃--N去除率均差异显著；②曝气4 h/d下美人蕉长势最好,并且在试验的第28天美人蕉株高达109 cm；③曝气4 h/d下ρ(DO)最高,并且对水体中营养盐的去除效果最好,试验至第28天,ρ(DO)为11.29 mg/L,TN、TP、COD_Cr、NH₃-N、NO₃--N去除率分别为75.10%、69.32%、65.75%、73.29%、78.79%；④试验至第28天,曝气4 h/d情况下美人蕉根际细菌总数达1.01×106 mL-1,显著高于曝气0、8和12 h/d下的细菌总数(分别为4.12×105、9.07×105、7.77×105 mL-1). 研究显示,该试验条件下,曝气4 h/d对水体中营养盐的去除效果最佳. 

Impact of Aeration Time on Nutrient Removal by Ecological Floating Bed of Canna indica in Polluted Water

Abstract:In order to study the effects of aeration time on nutrient removal by an ecological plant floating bed in water, an ecological floating bed of Canna indica was taken as the study object, and an experiment was conducted consisting of four groups:the control group and aeration times of 4,8 and 12 h/d. According to the pre-experiment, the aeration rate of 2.4 m3/(m2·d) was chosen. The heights of C. indica were measured on days 0,3, 5,7, 18 and 28, with tests on ρ(DO), ρ(TN), ρ(TP), ρ(COD_Cr), ρ(NH₃-N) and ρ(NO₃--N). After the experiment, the total amount of rhizosphere bacteria was also measured. The results showed that:1) The groups with aeration times 4 and 8 h/d had significant differences in ρ(DO) and removal rates of TN, TP, NH₃-N and NO₃--N from the control group. 2) The plant grew best in the group with aeration time 4 h/d, with plant height of 109 cm on day 28. 3) The group with aeration time 4 h/d had the highest DO and the best nutrient removal effect; the concentration of DO reached 11.29 mg/L, while the removal rates of TN, TP, COD_Cr, NH₃-N and NO₃--N reached 75.10%, 69.32%, 65.75%, 73.29% and 78.79% respectively on day 28. 4) The total amount of rhizosphere bacteria in the group with aeration time 4 h/d reached 1.01×106 mL-1, obviously higher than the other three groups; the control group and the groups with aeration times 8 and 12 h/d reached 4.12×105,9.07×105 and 7.77×105 mL-1 respectively on day 28. In conclusion, when the aeration rate was 2.4 m3/(m2·d), the aeration time of 4 h/d was helpful for cleaning the polluted water.