电解与紫外协同去除工厂化养殖循环水中氨氮效果研究

Removal Effect of Ammonia in RAS Using Electrochemical Process Combined with UV Irradiation

为探究电化学氧化法在工厂化循环水养殖系统中处理水质的效果及影响因素,在前期试验得到最佳条件(温度25℃、电流密度40 A/m2、水流速度300 m L/min)下,以不同初始氨氮质量浓度和固体悬浮颗粒物的模拟养殖水以及实际养殖水为研究对象,探讨了加入低压紫外汞灯后电解与紫外协同去除氨氮的效果。结果表明:电解紫外协同处理氨氮效果明显优于单独电解法,运用本系统处理氨氮初始质量浓度分别为4、7、10 mg/L的模拟养殖水时,氨氮去除效率相对于单独电解时分别提高45.0%(p<0.05)、36.0%(p<0.05)和20.0%(p<0.05);电解紫外协同去除氨氮效率受氨氮初始质量浓度、水体中的固体颗粒悬浮物、实际养殖水等因素影响,随着氨氮初始质量浓度及水体中固体悬浮颗粒物的升高,氨氮的去除效率降低,达到同种去除效率所需的时间延长,当处理固体悬浮颗粒(SS)分别为100、150、200 mg/L的模拟养殖水时,氨氮的去除效率随着SS的升高而降低,相对于仅含氨氮的模拟养殖水,氨氮的去除效率分别降低51.7%(p<0.05)、65.5%(p<0.05)和72.4%(p<0.05);在处理实际养殖水时,氨氮的去除速率明显降低,去除完全所需的时间延长,在本系统中电解紫外对氨氮、亚硝氮、固体悬浮颗粒物的去除具有较好效果,去除率分别为97.8%、96.9%和92.1%。

To explore the effect of water treatment and the influencing factors by using the electrochemical oxidation process in industrial recirculating aquaculture system, the research was conducted under the best condition with temperature of 25℃ , current density of 40 A/m^2 and flow rate of 300 mL/min, which was obtained by the former study. With different initial concentrations of ammonia nitrogen, suspended solid of simulated aquaculture water and actual aquaculture water of tilapia from the recirculating aquaculture lab of Zhejiang University, the removal rate of ammonia nitrogen was explored by using electrochemical process combined with UV irradiation. It demonstrated that the effect of using electrochemical process combined with UV irradiation was much better than that of single use of electrochemical process. Therefore, under initial concentrations of ammonia nitrogen at 4 mg/L, 7 mg/L and 10 mg/L of simulated aquaculture water, the removal rates of ammonia nitrogen were increased by 45.0% （p 〈0.05）, 36.0% （p 〈0.05） and 20.0% （p 〈0.05）, respectively. The initial concentration of ammonia nitrogen ,the suspended solid in the aquaculture water and the actual aquaculture water had important effects on removal efficiency of ammonia nitrogen, with the increase of initial concentration of ammonia nitrogen and concentration of suspended solid, the removal efficiency was reduced and the spending time was prolonged. For example, the treatment of different simulated aquaculture water with suspended solid of 100 mg/L, 150 mg/L, 200 mg/L, the removal rate of ammonia nitrogen was decreased with the increase of SS, compared with the simulated aquaculture water only containing ammonia nitrogen, the removal rates of ammonia nitrogen were decreased by 51.7% （p 〈 0.05） , 65.5% （p 〈 0.05） and 72.4% （p 〈 0.05） , respectively. When dealing with actual aquaculture water, although the system had great effects on the removal of ammonia nitrogen （the efficiency was 97.8% ）, nitrate nitrogen （the efficiency was 96.9% ） and suspended solid （the efficiency was 92. 1% ） , the removal rate of ammonia nitrogen was decreased and the time spent was prolonged.