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“水蚯蚓—微生物共生系统”泥水同步降解机理模型建立及校验

Study on the Model for Symbiotic System of Aquatic Worms with Microorganism and Its Validation

【作者】 马王钢

【导师】 孙培德;

【作者基本信息】 浙江工商大学 , 环境工程, 2011, 硕士

【摘要】 基于目前我国水污染治理和后续剩余污泥处置的现状,高效、节能、低碳的污水处理、污泥处置工艺已成为研究热点。“水蚯蚓-微生物共生系统”是指在污泥/污水生物处理工艺过程中引入水蚯蚓,延长和扩展系统食物链,丰富系统生物多样性,在实现污水净化的同时实现污泥减量。本文以水蚯蚓为主要研究对象,首次从水蚯蚓污泥减量的动力学角度出发,结合全耦合活性污泥模型FCASM3,建立“水蚯蚓-微生物共生系统”泥水同步降解机理模型,并顺利完成模型的现场校验工作。主要研究成果如下:1.以活性污泥为底物,水蚯蚓体重随培养时间的变化趋势较好地符合Gauss函数,最大比增长速率μmax=0.41d-1,最大产率系数Yw/s=0.32;底物浓度和溶解氧浓度由低到高变化时,水蚯蚓比增长速率与底物浓度、溶解氧浓度之间的关系满足Monod方程;底物浓度对水蚯蚓生长速率的影响要大于溶解氧浓度,水蚯蚓可以在溶解氧浓度较低的环境中生长。单从底物条件考虑,污泥浓度2000-6000mg/L左右的系统都适合水蚯蚓的生长,污泥浓度在4000-6000mg/L时,水蚯蚓可以获得较大的比生长速率。2.基于水蚯蚓在活性污泥、灭活污泥及蒸馏水系统中的批量培养试验,考察了水蚯蚓污泥减量过程中营养盐的释放规律。结果表明水蚯蚓活体代谢过程中主要释放的营养盐是NH4+-N和P043-P;水蚯蚓在活性污泥、灭活污泥中释放NH4+-N速率为0.060和0.051mg NH4+-N/g Worms·d-1;释放P043-P速率为0.029和0.023 mgPO43--P/g Worms·d-1。3.在充分分析“水蚯蚓-微生物共生系统”中水蚯蚓与微生物、微生物与微生物之间两两相互作用的基础上,从水蚯蚓动力学角度出发,结合全耦合活性污泥3号模型(FCASM3)建立了“水蚯蚓-微生物共生系统”泥水同步降解机理模型。4.以浙江省某污水处理厂作为“水蚯蚓-微生物共生系统”机理模型校验的现场试验基地,通过现场试验,完成了对“水蚯蚓-微生物共生系统”机理模型的校验工作。动态模拟结果表明:“水蚯蚓-微生物共生系统”机理模型实现了对污水处理厂生物去除有机物及脱氮过程进行精确模拟,而对生物除磷过程的模拟,由于该污水处理厂低磷进水的原因,与实测值存在一定的偏差。此外与黑箱模型的对比研究表明“水蚯蚓-微生物共生系统”机理模型的准确度要普遍高于“水蚯蚓-微生物共生系统”黑箱模型,并解决了黑箱模型对N03--N模拟较不准确的问题。

【Abstract】 The treatment and disposal of excess sludge has become a rising challenge for wastewater treatment plants (WWTPs) in China. Being energy-saving and low-carbon, the potential of using aquatic worms on sludge ruduction has attached more and more attention. The symbiotic minitype ecological system formed by wastewater, microorganism (bacteria, fungus) and minitype animal (aquatic worms), which has sludge reduction and wastewater treatment effect, is called symbiotic system of aquatic worms and microorganism.Therefore, in this thesis, we chosed aquatic worms as a research object. The model for symbiotic system of aquatic worms with microorganism was developed based on the fully coupled activated sludge model (FCASM3) and the growth kinetics of aquatic worms feeding on activated sludge. The principal conclusions were obtained as follows.1. The growth kinetics of aquatic worms was investigated from juvenile to decline phase for 18 weeks by cultivating with activated sludge in batch test. Results showed that the growth of aquatic worms well fit the Gauss curve for cultivating 18 weeks. The maximum specific growth rate of aquatic wormsμmax=0.41d-1 and the maximum growth yield of aquatic worms Yw/s=0.32. The relationship between the specific growth rate of aquatic worms with dissolved oxygen and sludge concentration meet the Monod equation. The sludge concentration had greater effect on the growth kinetics of aquatic worms, aquatic worms can live in the environment with low dissolved oxygen. Aquatic worms can get a rapid growth rate when the sludge concentration was 4000-6000mg/L2.The nutrient released by aquatic worms was investigated in this research, feeding on activated sludge, sterilized sludge and distilled water respectively. Results showed that the nutrient released by aquatic worms were NH4+-N and PO43--P mainly. The NH4+-N released rates were 0.060 and 0.051mg NH4+-N/g Worms·d-1 respectively, feeding with activated sludge and sterilized sludge. The PO43--P released rates were 0.029 and 0.023 mgPO43--P/g Worms·d-1 respectively, feeding with activated sludge and sterilized sludge. 3. According to the interaction mechanism between aquatic worms and microorganism in the symbiotic system. The model of symbiotic system of aquatic worms with microorganism was developed based on the fully coupled activated sludge model (FCASM3) and the growth kinetics of aquatic worms feeding on activated sludge.4. The model of symbiotic system of aquatic worms with microorganism was established for the novel oxidation ditch in WWTP. The validation of this new model was completed based on the results of influent component measurement and respirometric experiments. The dynamic simulation results indicated that it could simulate biological carbon and nitrogen removal processes accurately, but the description of phosphorus removal deviated from measurement due to the low phosphorus level in the influent. Compare with the black-box model, the accuracy of the model of symbiotic system microorganism was higher. Moreover, the model of symbiotic system sloved the problem of NO3-N which has not been sloved by the black-box model.

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