海水生物滤器除氮性能及硝化动力学研究

Study on total ammonia nitrogen removal performance of marine biofilters and nitrification kinetics

生物滤器是封闭循环水养殖系统的关键水处理单元,主要用于去除水体中的氮化物。采用人工模拟海水养殖废水,在系统运行的水力停留时间为30 min,水温为14-25℃,pH为8.05-8.53条件下,对4种填料生物滤器的挂膜过程及其氨氮去除性能差异进行了实验研究,结果表明：在0.5 mg/L的进水氨氮浓度条件下,竹环、麦饭石、陶粒和塑料生物滤球4种填料生物滤器的最大氨氮去除速率分别为331.38、425.73、310.38和128.24 mg/（m^3.h）,竹环填料滤器的出水亚氮较低,小于0.07 mg/L,麦饭石和陶粒填料滤器的出水亚氮较高,峰值分别达0.28 mg/L和0.13 mg/L;从除氮性能、造价、能耗等方面综合考虑,竹环填料的性能优于其他3种填料。研究了竹环填料生物滤器处理海水养殖废水的硝化动力学特性,实验结果表明：用Monod方程能够很好地表达养殖废水处理的硝化动力学,并用积分法求得反应动力学常数：最大氨氮去除速率Vmax=1 828.70 mg/（m^3.h）,半饱和常数Ks=0.3916 mg/L,且R^2=0.9752。经过模型验证,建立的动力学方程能预测实际状况。

Biofilter is the key water treatment unit of marine recirculating aquaculture system（RAS）,and it plays an important role in water-soluble nitrogen removal.A pilot-scale experiment study was carried out with synthetic aquacultural wastewater.The hydraulic retention time,temperature and pH were 1 hour,18～25℃ and 8.05～8.53,respectively.The membrane hanging process and comparison of total ammonia nitrogen（TAN） removal rate were examined in the marine biofilters packed with four substrates.Experimental results showed that within the lower TAN concentration of 0.5 mg/L,the maximum TAN removal rate of bamboo,maifan stone,ceramic pellets,plastic bead biofilters were 331.38,425.73,310.38 and 128.24 mg/（m^3·h）,respectively.The effluent NO2-N concentration of bamboo biofilter was lowest and less than 0.7 mg/L,however,effluent NO2-N concentration of maifan stone and ceramic pellets biofilter were higher with their peak values of 0.28 and 0.13 mg/L.According to the TAN removal efficiency,cost and power consumption,bamboo substrate is superior to others.Kinetic characteristic for mariculture wastewater treatment was studied in bamboo substrate biofilter.The experimental results indicated that the steady-state kinetics of substrate removal could be described by the Monod-type expression and kinetics parameters were evaluated by integral method： Vmax=1 828.70 mg/（m^3·h）,Ks=0.3916 mg/L,R2=0.9752.It could be successful application in the kinetic model for prediction of TAN removal rate by validating.