Dahlen Elizabeth P, Rittmann Bruce E
ChemRisk, Inc., San Francisco, CA 94105-2703, USA.
Biodegradation. 2006 Jun;17(3):237-50. doi: 10.1007/s10532-005-5019-8.
The two-tank accelerator/aerator modification of activated sludge significantly increases the biodegradation of hydrocarbons requiring initial monooxygenation reactions, such as phenol and 2,4-dichlorophenol (DCP). The small accelerator tank has a controlled low dissolved oxygen (DO) concentration that can enrich the biomass in NADH + H+. It also has a very high specific growth rate (mu acc) that up-regulates the biomass's content of the monooxygenase enzyme. Here, we develop and test the ACCEL model, which quantifies all key phenomena taking place when the accelerator/aerator system is used to enhance biodegradation of hydrocarbons requiring initial monooxygenations. Monooxygenation kinetics follow a multiplicative relationship in which the organic substrates (phenol or DCP) and DO have separate Monod terms, while the biomass's content of NADH + H+ has a first-order term. The monooxygenase enzyme has different affinities (K values) for phenol and DCP. The biomass's NADH + H+ content is based on a proportioning of NAD(H) according to the relative rates of NADH + H+ sources and sinks. Biomass synthesis occurs simultaneously through utilization of acetate, phenol, and DCP, but each has its own true yield. The ACCEL model accurately simulates all trends for one-tank and two-tank experiments in which acetate, phenol, and DCP are biodegraded together. In particular, DCP removal is affected most by DOacc and the retention-time ratio, Theta acc/Theta total. Adding an accelerator tank dramatically increases DCP removal, and the best DCP removal occurs for 0.2 < DOacc < 0.5 mg/l and 0.08 < Theta acc/Theta total < 0.2. The rates of phenol and DCP utilization follow the multiplicative relationship with a maximum specific rate coefficient proportional to mu acc. Finally, mu acc increases rapidly for Theta acc/Theta total < 0.25, acetate removal in the accelerator fuels the high mu acc, and the biomass's NADH + H+ content increases very dramatically for DO acc < 0.25 mg/l.
活性污泥的双池加速/曝气改良显著提高了需要初始单加氧反应的碳氢化合物的生物降解能力，如苯酚和2,4 - 二氯苯酚（DCP）。小型加速池具有可控的低溶解氧（DO）浓度，可富集生物量中的NADH + H⁺。它还具有非常高的比生长速率（μacc），可上调生物量中单加氧酶的含量。在此，我们开发并测试了ACCEL模型，该模型量化了使用加速/曝气系统增强需要初始单加氧反应的碳氢化合物生物降解时发生的所有关键现象。单加氧动力学遵循乘法关系，其中有机底物（苯酚或DCP）和DO具有单独的莫诺德项，而生物量中NADH + H⁺的含量具有一阶项。单加氧酶对苯酚和DCP具有不同的亲和力（K值）。生物量中NADH + H⁺的含量基于根据NADH + H⁺源和汇的相对速率对NAD(H)进行的比例分配。生物量合成通过利用乙酸盐、苯酚和DCP同时发生，但每种都有其自身的真实产率。ACCEL模型准确模拟了乙酸盐、苯酚和DCP一起生物降解的单池和双池实验的所有趋势。特别是，DCP去除受DOacc和停留时间比Theta acc/Theta total影响最大。添加加速池可显著提高DCP去除率，最佳DCP去除发生在0.2 < DOacc < 0.5 mg/l和0.08 < Theta acc/Theta total < 0.2时。苯酚和DCP的利用速率遵循乘法关系，最大比速率系数与μacc成正比。最后，当Theta acc/Theta total < 0.25时，μacc迅速增加，加速池中乙酸盐的去除促进了高μacc，并且当DO acc < 0.25 mg/l时，生物量中NADH + H⁺的含量急剧增加。
