本研究考察了无机废水中氮负荷对好氧颗粒污泥(AGS)稳定性的影响。接种储存的AGS启动序批式反应器(SBR)，采用好氧-(缺氧+外加碳源)-好氧交替运行模式，在运行过程中逐步将氮负荷由0。3 kg N/(m3·d)提升至0。6 kg N/(m3·d)。前40 d内，进水氮负荷为0。3 kg N/(m3·d)，30 min污泥容积指数(SVI30)在30～45 mL/g范围内波动，硝化菌比耗氧速率(SOURN)呈减小趋势(13。50～8。10 mg O2/(g SS·h))。41～70 d内，逐渐将进水氮负荷提升至0。6 kg N/(m3·d)，在氮负荷冲击下，部分AGS破碎。随着絮体污泥大量排出及破碎颗粒的生长，系统在第104 d完成重新造粒，AGS的平均粒径为1。4 mm。144 d后，AGS的理化性质趋于稳定，污泥浓度稳定在8 600～9 060 mg/L，颗粒化率保持在95％以上。139 d后，AGS对氨氮和总无机氮的去除率分别为90％和80％以上，由于游离亚硝酸(FNA)对亚硝酸盐氧化菌的抑制作用，脱氮途径逐渐转变为短程硝化反硝化。氮负荷提升后，硝化菌如Nitrosomonas(0。2％～12。1％)和反硝化细菌如Thauera (10。4％～21。6％)的相对丰度明显提高，表现出较传统工艺更强的脱氮性能。
Effect of nitrogen loading rate on nitrogen removal performance and stability of aerobic granular sludge for treating inorganic wastewater
This paper investigated the effect of nitrogen loading rate(NLR)on the stability of aerobic granular sludge(AGS)in the treatment of inorganic wastewater.The sequencing batch reactor(SBR)was started by inoculating stored AGS and was operated in alternating oxic-anoxic/external carbon source-oxic operational mode.In addition,the NLR was increased stepwise from 0.3 kg N/(m3·d)to 0.6 kg N/(m3·d)during the operation.In the former 40 days,the NLR was 0.3 kg N/(m3·d),the sludge volume index(SVI30)fluctuated between 30-45 mL/g,and the specific oxygen consumption rate of nitrifying bacteria(SOURN)showed a decreasing trend(13.50-8.10 mg O2/(g SS·h)).The NLR was gradually increased to 0.6 kg N/(m3·d)from 41 d to 70 d,and some AGS broke due to the impact of the NLR.With the washout of quantities of flocs and the growth of broken granules,the system successfully re-granulated on the 104th day,and the average particle size stabilized at 1.4 mm thereafter.After 144 days,the physicochemical properties of AGS tended to be stable,the sludge concentration was stable at 8 600-9 060 mg/L,and the granulation rate remained above 95% .After 139 d,the removal rates of ammonia nitrogen and total inorganic nitrogen by AGS remained above 90% and 80%,respectively.Due to the inhibition effect of free nitrite(FNA)on nitrite-oxidizing bacteria,the nitrogen removal pathway gradually changed to partial nitrification and denitrification.After increasing the NLR,the relative abundance of nitrifying bacteria such as Nitrosomonas(0.2%-12.1% )and denitrifying bacteria such as Thauera(10.4%-21.6% )increased significantly,showing stronger nitrogen removal ability compared with the conventional process.
万方数据
维普
