海水养殖废水生物膜反应器快速启动研究

Biofilm Reactor Fast Startup for Seawater Aquaculture Wastewater Treatment

针对微污染海水养殖废水生物膜氨氧化工艺处理中启动时间长、处理效果不佳等问题,开展了不同种类营养强化方式(NH_4^+-N/PO_4^(3-)-P/TOC)对生物膜工艺启动过程氨氧化性能影响研究。结果表明,微污染养殖废水水质下启动生物膜反应器需要30 d度过缓滞期并于42 d获得成熟生物膜,通过增加有机物水平进一步抑制生物膜氨氧化性能,而增加NH_4^+-N负荷(2.70~25.44 mg/L)和PO_4^(3-)-P负荷(0.01~0.41 mg/L)均能有效提高氨氮去除性能和缩短反应器启动时间。其中,尤以提高NH_4^+-N负荷效果最佳,当NH_4^+-N负荷分别增至11.53 mg/L(C/N=0.2)和25.44 mg/L(C/N=0.4)时,反应器进入稳定期时间分别仅需12 d(反应器N3)和10 d(反应器N4)。系统稳定后调节进水负荷至养殖废水水质,各组反应器中N3氨氮去除速率最高(0.38 mg/(L·h)),且出水氨氮≤0.02 mg/L;并采用Monod方程获得N3生物膜半饱和常数Ks值(0.08 mg/L)明显低于反应器N4(3.37 mg/L)。为此,增加进水NH_4^+-N负荷至11.53 mg/L(C/N=0.2)左右启动生物膜反应器,能更加有效同步缩短反应器启动时间和提升氨氮去除效率。

Due to the slow microbial growth and poor treatment efficiencies of micro-polluted seawater circulating aquaculture wastewater biofilm treatment,the effects of different nutrients such as organics,ammonia,phosphate on the ammonia oxidization during biofilm startup were examined in this study. It was shown that the biofilm reactor fed with micro-polluted seawater circulating aquaculture wastewater required 30 d to pass lag phase and 42 d to step into stable phase.The increase of organics further inhibited ammonia removal,but the increase of NH_4~＋-N concentrations（2.70~25.44 mg/L）and PO_4^（3-）-P concentrations（0.01 ~0.41 mg/L） could simultaneously enhance NH_4~＋-N removal and shorten the period of biofilm startup,in which increase of NH_4~＋-N loadings were much more efficient than others. As the influent NH_4~＋-N loadings was increased up to 11.53 mg/L（C/N ratio=0.2） and 25.44 mg/L（C/N ratio=0.4）,the periods of biofilm startup were only12 d and 10 d,respectively. When the influent characteristics adjusted to aquaculture wastewater,the highest ammonia removal rate occurred in reactor N3（0.38 mg/（L·h））,with the effluent NH_4~＋-N concentrations ≤0.02 mg/L,satisfying the water quality standard for fisheries（GB 11607-89）. Furthermore,the Monod model demonstrated that biofilm in reactor N3 had a lower half saturation constant Ks（0.08 mg/L） than that of N4（3.37 mg/L）. Hence,the increase of NH_4~＋- N to 11.53 mg/L（C/N ratio=0.2）was efficient to simultaneously improve ammonia removal and shorten biofilm start-up period.