A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflo...A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflow anaerobic sludge bed（UASB） and expanded granular sludge bed（EGSB） reactors. The effects of pH value and temperature on toxicity of ammonia nitrogen to anaerobes were investigated. The results show that the specific methanogenic activity of anaerobic granular sludge suffers inhibition from ammonia nitrogen, the concentrations of ammonia nitrogen that produce 50 % inhibition of specific methanogenic activity for sludge from UASB and EGSB reactor are 2.35 and 2.75 g/L, respectively. Hydrogen utilizing methanogens suffers less inhibition from ammonia mtrogen than that of acetate utilizing methanogens. Hydrogen-producing acetogens that utilize propionate and butyrate as substrates suffer serious inhibition from ammonia nitrogen. The toxicity of ammonia nitrogen to anaerobic granular sludge enhances when pH value and temperature increase. Anaerobic granular sludge can bear higher concentrations of ammonia nitrogen after being acclimated by ammonia nitrogen for 7 d.展开更多
为解决城市污水处理过程出水氨氮浓度难以实时精准测量的问题,构建了一种融合卷积层和注意力机制的长短期记忆网络(convolutional layer and squeeze-and-excitation attention mechanism based long short-term memory network,CSA-LS...为解决城市污水处理过程出水氨氮浓度难以实时精准测量的问题,构建了一种融合卷积层和注意力机制的长短期记忆网络(convolutional layer and squeeze-and-excitation attention mechanism based long short-term memory network,CSA-LSTM)模型。首先,通过引入卷积层(convolutional layer,CL)深度提取数据中的非线性特征,并通过注意力机制(squeeze-and-excitation attention mechanism,SEAM)自适应分配特征通道的权重,实现特征解耦;其次,长短期记忆网络(long short-term memory network,LSTM)提取时间序列数据长期依赖关系,实现出水氨氮浓度的实时预测;然后,提出一种具有自适应采集函数的贝叶斯优化算法,实现模型参数优化,进一步提高模型精度;最后,基于基准实验和实际污水处理厂数据测试CSA-LSTM的有效性。结果表明,模型具有较高的出水氨氮浓度预测精度,能够有效应对城市污水处理中数据的强非线性、耦合性以及时间依赖性问题,具有良好的泛化能力。展开更多
文摘A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflow anaerobic sludge bed（UASB） and expanded granular sludge bed（EGSB） reactors. The effects of pH value and temperature on toxicity of ammonia nitrogen to anaerobes were investigated. The results show that the specific methanogenic activity of anaerobic granular sludge suffers inhibition from ammonia nitrogen, the concentrations of ammonia nitrogen that produce 50 % inhibition of specific methanogenic activity for sludge from UASB and EGSB reactor are 2.35 and 2.75 g/L, respectively. Hydrogen utilizing methanogens suffers less inhibition from ammonia mtrogen than that of acetate utilizing methanogens. Hydrogen-producing acetogens that utilize propionate and butyrate as substrates suffer serious inhibition from ammonia nitrogen. The toxicity of ammonia nitrogen to anaerobic granular sludge enhances when pH value and temperature increase. Anaerobic granular sludge can bear higher concentrations of ammonia nitrogen after being acclimated by ammonia nitrogen for 7 d.
