有机碳源环境下的厌氧氨氧化批式实验

通过厌氧氨氧化批式实验,研究了在有机碳源环境下COD/NH4 -N比、pH值以及NO2--N浓度对厌氧氨氧化反应的影响.结果表明:在有机碳源环境下,厌氧氨氧化作用和反硝化作用可以同时存在;适宜的COD/NH4 -N比值范围在0~1.57之间;适宜的pH值范围应该在6.02~8.50之间,最适pH值为8.00;为了得到较好的脱碳和脱氮效果,在初始COD值为300mg/L时,初始NO2--N浓度不宜超过500mg/L,否则会抑制厌氧氨氧化反应和反硝化反应的进行.     

厌氧序批式反应器培养厌氧氨氧化污泥

为从厌氧序批式反应器中接种好氧硝化污泥,对厌氧氨氧化污泥的培养进行了研究.采用含氮模拟废水,在进水pH值为7.2-7.8、温度为(30±1)℃的条件下运行142d,成功培养出厌氧氨氧化污泥.实验结果表明:在水力停留时间为1.2d、总氮容积负荷(以N计) 为0.4318kg/(m3·d)时,总氮去除率最高达到93.3%,平均为80.5%;氨氮和亚硝酸盐氮的去除率最高达到93.9%和99.8%,平均为81.2%和85.7%;氨氮和亚硝酸盐氮去除的比例(摩尔比)为1:(1.387±0.024),反应器内主要发生厌养氨氧化反应,说明采用厌氧序批式反应器是培养厌氧氨氧化污泥的一条途经.     

Topological properties of non-Hermitian Creutz ladders

We study topological properties of the one-dimensional Creutz ladder model with different non-Hermitian asymmetric hoppings and on-site imaginary potentials,and obtain phase diagrams regarding the presence and absence of an energy gap and in-gap edge modes.The non-Hermitian skin effect(NHSE),which is known to break the bulk-boundary correspondence(BBC),emerges in the system only when the non-Hermiticity induces certain unbalanced non-reciprocity along the ladder.The topological properties of the model are found to be more sophisticated than that of its Hermitian counterpart,whether with or without the NHSE.In one scenario without the NHSE,the topological winding is found to exist in a two-dimensional plane embedded in a four-dimensional space of the complex Hamiltonian vector.The NHSE itself also possesses some unusual behaviors in this system,including a high spectral winding without the presence of long-range hoppings,and a competition between two types of the NHSE,with the same and opposite inverse localization lengths for the two bands,respectively.Furthermore,it is found that the NHSE in this model does not always break the conventional BBC,which is also associated with whether the band gap closes at exceptional points under the periodic boundary condition.