不同有机碳源及C/N对生物滤池净化效果的影响

Effect of Different Organic Carbon Sources and C/N on the Bio-filter Purification

利用生物滤池模拟装置,以实际养殖废水为处理对象,探讨了4种常见有机碳源(葡萄糖、乙醇、红糖和淀粉)及不同碳氮比对有机物去除、硝化反应和异养反硝化作用等生物滤池主要净化过程的影响。碳源初选结果显示,同种碳源下,当C/N从0升高至6过程中,生物滤池对TAN(总氨氮)的去除率呈先升高后降低趋势;当C/N较小时,各组对NO_2^--N的去除率差异性不显著(P>0.05),随着C/N继续升高,NO_2^--N去除率则显著降低(P<0.05);乙醇组除外,其他3组随着C/N升高,COD_(Mn)去除率先迅速增大然后趋于稳定;各组NO_3^--N和TN去除率呈先升高后降低趋势,且变化显著(P<0.05),当C/N=4时,分别达到最高值。碳源复选结果显示,在C/N=4条件下,分别添加有机碳源(乙醇、淀粉、红糖和葡萄糖)的4组对TAN、NO_3^--N、TN和COD_(Mn)的去除率显著高于对照组(P<0.05);而对照组NO_2^--N的去除率最高,达到93.59%;添加乙醇,生物滤池对水体中TAN、NO_2^--N、NO_3^--N和TN的去除效果优于其他3种碳源。研究表明,当C/N=4时,乙醇作为外加碳源能很好地提高生物滤池的净化效率。

Biofilters have been applied in the primary purification of wastewater that is the removal of organic compounds, nitrification and heterotrophic denitrification. In this paper we investigated how different organic carbon sources （glucose, ethanol, brown sugar and starch） and the carbon-nitrogen ratios affect the primary purification efficiency of biofilters, using biofilter simulators and real aquaculture wastewater as the subject. The preliminary screening results showed that in the same carbon source group, the removal rate of ammonium nitrogen first increased and then decreased as the C/N ratio changed from 0 to 6. There was no significant difference in the removal rate of nitrite between different carbon source groups when the C/N ratio was low （P〉0.05）. As the C/N ratio continued to increase, the removal rate of nitrite was significantly reduced （P〈0.05）. Along with the increase in the C/N ratio, the removal rate of CODMn first increased rapidly and then stabilized in all carbon source groups except for ethanol. The removal rates of both nitrate and total nitrogen first increased followed by a decreased in each group exhibiting significant variation （P〈0.05）. Both rates reached the maximum when the C/N ratio was four. The rescreening results of carbon sources showed that when the C/N ratio was four, the removal rates of ammonium nitrogen, nitrate, total nitrogen and CODMn in all four groups were significantly higher than that in the control group （P〈0.05）. The removal rate of nitrite was the highest in the control group that was 93.59%. The removal efficiency of the biological aerated filter for TAN, NO2^--N, NO3^--N and TN in the ethanol group was higher than that in the other three groups. Our comprehensive analysis suggested that ethanol carbon source and a proper C/N ratio （4：1） could largely improve the purification efficiency of the biofilter.