Mathematical model for meso- and thermophilic anaerobic sewage sludge digestion
Mathematical model for meso- and thermophilic anaerobic sewage sludge digestion
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DOI：
10.1021/es010139p
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发表时间：
2002-03-01
影响因子：
11.4
通讯作者：
Gujer, W
中科院分区：
文献类型：
--
作者：
Siegrist, H;Vogt, D;Gujer, W
开发了一个数学模型来描述嗜温（35 +/- 5 摄氏度）和嗜热消化（55 +/- 5 摄氏度）的动态行为。特别强调的是，醋营养产甲烷和丙酸盐降解是决定厌氧消化稳定性的步骤，以及水解速率，它决定颗粒可降解有机碳的降解效率。在6-20天（中温）和2-8天（嗜热）水力停留时间（HRT）范围内，观察到的醋营养产甲烷菌的最大生长速率分别为0.33和1.3d(-1)，衰减率为15%。确定了温度和 pH 值依赖性以及氨对乙酸盐和丙酸盐转化的抑制并将其包含在模型中，这使我们能够模拟添加富含蛋白质和氮的废物的效果以及在高 pH 条件下暂时增加游离氨的后果。在相同的游离氨范围内没有观察到氢转化的抑制。最适pH值在6.6和7.3之间。 pH 值低于 6.2 时，醋酸营养型产甲烷作用受到强烈抑制，而 pH 值高于 7.4 时，则可被游离氨抑制。对于使用普通城市污水污泥的消化池，游离氨对乙酸盐转化的抑制导致在中温（HRT = 20 d）和嗜热（HRT = 6 d）条件下乙酸盐分别增加约35和140 mg N/L。这两种条件下的水解速率常数分别为0.25和0.4 d(-1)。该模型通过实验室和全尺寸消化池中的阶跃负载和冲击负载的负载变化实验进行了验证。
A mathematical model is developed to describe the dynamic behavior of mesophilic (35 +/- 5 degreesC) and thermophilic digestion (55 +/- 5 degreesC). Special emphasis is given-to acetotrophic methanogenesis and propionate degradation, as the steps that determine the stability of anaerobic digestion, as well as to hydrolysis rate, which determines the degradation efficiency of particulate degradable organic carbon. Within the range of 6-20 (mesophilic) and 2-8 d (thermophilic) hydraulic retention time (HRT), the observed maximum growth rates for acetotrophic methanogens are 0.33 and 1.3 d(-1), respectively, with a 15% decay rate. Temperature and pH dependence as well as ammonia inhibition of acetate and propionate conversion are determined and included in the model, which allows us to simulate the effect of protein- and nitrogen-rich waste addition and the consequences of temporarily increased free ammonia at high pH. No inhibition of hydrogen conversion was observed in the same free ammonia range. The pH optimum is between 6.6 and 7.3. Acetotrophic methanogenesis is strongly inhibited below pH 6.2, whereas above pH 7.4 it can be inhibited by free ammonia. For digesters fed with ordinary municipal sewage sludge, free ammonia inhibition of acetate conversion leads to an increase in acetate at about 35 and 140 mg of N/L for mesophilic (HRT = 20 d) and thermaphilic (HRT = 6 d) conditions, respectively. The hydrolysis rate constant is 0.25 and 0.4 d(-1) respectively for these two conditions. The model is validated with load variation experiments in laboratory and full-scale digesters for step and shock loads.