Impacts of hydraulic retention time and temperature on the purifying effects of canna artificial floating island

摘要

In order to improve the purifying effects of canna artificial floating island, the simulation cultivation experiment was used to explore the improvement on water of Youth Lake (located in Shenyang, Liaoning Province, China) by canna artificial floating island. The results show that canna presents good effects to remove nitrogen and phosphorus in several kinds of eutrophic waters. The initial total nitrogen (TN) and total phosphorus (TP) concentrations are 8.34-20.45 mg/L and 0.78-1.51 mg/L, and the average TN and TP removal rates are 63.34% and 61.75%. Canna significantly improves the N and P removal rates in water. With the extension of hydraulic retention time (HRT), the average TN and TP removal rates gradually increase. When HRT is increased from 1 day to 7 days, the TN removal rate is increased to 18.11% from 9.5%, and the TP removal rate is increased to 50.57% from 31.54%. Under the same temperature, canna's TN and TP removal rates increase as the purification days increase. The optimum temperature to remove TN and TP is 29°C.