【作者】 李杰；

【导师】 王志盈；

【作者基本信息】 西安建筑科技大学 ， 环境工程， 2008， 博士

【摘要】 随着生物脱氮除磷及难降解有机废水处理研究的深入,对传统活性污泥法的处理能力提出了更高的要求,通过增加微生物活性和生物多样性以提高生化处理效果的技术受到日益重视。以载体为依托的生物膜法可以形成生物量大、生物相丰富的载体污泥,但载体污泥性能的好坏取决于载体性能。上世纪90年代中期发展起来的悬浮载体生物膜法,吸收了传统流化床和生物接触氧化法两者的优点,成为一种新型高效的污水处理方法。其技术原理就是将小比重的悬浮载体直接投加到曝气池中,使活性污泥附着到载体上,形成高生物密度、高生物活性、生物相丰富的载体微生物集团,以提高生化处理的效果和效率,所以性能优越的悬浮载体的开发研制,对强化活性污泥的处理功能,提高生化处理效率具有重要意义。本文采用超声波分散的方法制得纳米凹凸棒土（Attapulgite nanoocomposites,简称AT）,通过机械共混的方法介入聚乙烯醇与甲醛的缩合反应中,通过催化、交联、发泡制备出新型纳米生物载体AT-PVF。再将其应用于普通SBR工艺中,形成序批式悬浮载体生物膜反应器（Sequencing Batch Adsorption Immobilization SuspendedCarrier Reactor,简称AI-SBR）工艺。通过平行试验比较了AI-SBR和普通SBR的启动性能、抗温度、pH、有机负荷、苯酚和Cr⁺⁶毒性影响的能力及对生活污水和实际化工废水的处理效果;进行了载体微生物的生物量、生物活性、生物相及对不良环境变化的抵抗能力,AT-PVF的微生物附着动力学和AI-SBR污染物降解动力学研究。检验了开发的新型生物载体的实用性和优越性,比较了普通活性污泥在形成载体微生物污泥前后微生物特性及应用性能的变化,研究了AI-SBR的应用优势。得出如下主要成果:（1）在PVA13%,甲醛对PVA的重量比0.75,H₂SO₄对PVA的重量比1.0,表面活性剂0.5%,AT 0.4%的条件下,通过催化、交联、发泡制备出物理和生化性能良好的新型纳米生物载体AT-PVF。（2）通过与环保海绵（目前国内实际应用效果最好的功能泡沫塑料生物载体）的物化、生化性能比较,AT-PVF载体的抗拉强度为2.38MPa,是环保海绵的1.23倍;孔径范围大,空隙均匀,开孔程度和孔壁粗糙度远大于环保海绵,并有许多褶皱,微生物的附着与物质的传递性能均优于环保海绵;相同条件下,AT-PVF挂膜速度快,5d就可以全部挂膜,比环保海绵快2d。COD去除率为96.2%,比环保海绵高出6%,氨氮去除率为95.3%,比环保海绵高出7%,污泥量是环保海绵的1.3倍。（3）将AT-PVF载体应用于传统的SBR工艺中,使普通活性污泥附着到载体上,形成悬浮载体微生物污水处理体系,即AI-SBR工艺。通过AI-SBR与SBR平行试验得出AI-SBR启动速度快,抗冲击能力强,处理效果好,载体微生物生物量大,在反应器运行6d和210d时,AT-PVF的微生物密度达到15.2 mg/cm³和44.3mg/cm³,约是普通活性污泥的4.11倍。载体微生物生物活性高、生物相丰富,对不良环境的抵抗能力增强。（4）载体微生物在曝气池中使用时,在曝气池底曝气设备以上与正常水位以下约30cm处设置上下两层拦截网,将载体微生物以2-3cm³的块状、60%左右的填充率放入网内,使用效果最好。在SBR中使用时,下部拦截网设在池底曝气设备以上,上部拦截网设在最高水位与最低水位中间为宜,同时还需设置竖向拦截网将滗水器隔开。网内的载体微生物在使用过程中可以起到“主动拦截”作用,使出水中SS接近沉淀后出水。对于曝气池,可以减轻二沉池负担;对于SBR池,可以缩短甚至省去沉淀阶段,缩短处理周期,增加SBR的处理能力。（5）微生物在多孔立体网状载体上附着形成生物膜的过程分为可逆附着、不可逆附着和微生物繁殖生长过程。可逆附着发生在微生物和载体接触后的30min内,不可逆附着发生在微生物和载体接触后的40-300min内,300min以后,载体上附着的微生物开始大量生长增殖。可逆附着过程中,可用B=（?）表示载体上附着的微生物量（B）随时间t的变化关系,其中B_max为可逆附着中单位体积载体的微生物最大附着量,直接影响附着速度和附着量的大小,数值越大越好。α为微生物总附着常数,数值越大,可逆附着过程中载体上微生物达到最大生物附着量的时间越短。对于AT-PVF载体,B_max=8.23mg/cm³,α=0.04min^-1,不可逆附着过程中,可用B=（?）表示载体上附着的微生物量（B）随时间t的变化关系,其中B₀为不可逆附着开始时单位体积载体中微生物的附着量,直接影响不可逆附着速度和最终附着量的大小,数值越大越好。α’₃为微生物附着速率常数,数值越大,不可逆附着过程中微生物在载体上的附着速度越快。对于AT-PVF载体,B₀=2.287mg/cm³,a’₃为0.085min^-1。B_max和a、B₀和a’₃可作为衡量生物载体使用性能好坏的指标。（6）载体微生物COD的降解符合Monod一级反应动力学方程。不同温度和pH下,AI-SBR的一级降解动力学常数K_COD均大于SBR。SBR和AI-SBR的氨氮降解符合Monod动力学方程。SBR的氨氮最大降解速率V_max=16.581m/L（反应液）·h,半饱和常数Ks=40.65m/L。AI-SBR的Vmhx=24.078m/L（反应液）·h,是SBR的1.5倍,充分显示出优越的氨氮降解性能,Ks=22.99mg/L,小于SBR,说明AI-SBR在较低氨氮浓度下即可达到最大降解速率。整个试验结果表明,普通活性污泥经附着后形成的载体污泥,生物活性提高、对环境变化适应性增强、生物相更加丰富。将新研制的AT-PVF载体应用于SBR工艺中形成的AI-SBR工艺,与普通SBR相比,载体性能优良,生化处理性能和抗不良环境影响能力得到提高。更多还原

【Abstract】 Along with the research of biological nitrogen removal and biorefractory organic pollutants treatment, some requirements for raising the treating capacity of traditional activated sludge process are provided. So technology enhancing the efficiency of biological methods by increasing microbial activity and biodiversity received increasing attention. Carriers’ sludge which has high biomass and biofacies formed in carriers of biomembrance technique. It’s performance depend on carriers’ performance. At the middle of 90’s, suspended carrier biofilm absorption of advantages of fluidized bed and biological contact oxidation process has become one kind of new and high efficient wastewater treatment method. It’s principle is add suspended carrier to aeration tank in order to forming microorganism sludge of high biological density, biological activity and rich biofacies in carriers, So the biochemical treatment efficiency is improved. Researches on superior capability suspended carrier become the focal point studied at present.In this paper, we took attapulgite nanoocomposites powder by ultrasonic dispersion into between entrapment method and carrier-bound method by mechanical blending process. Physical physical and biological activity of carries as evaluation index, through improving upon PVF carrier-bound carries, AT-PVF carrier-bound carries was obtained. Then combined SBR with immobilized microbial carriers, Sequencing Batch Adsorption Immobilization Reactor （AI-SBR） was formed. Starting performance, ability of resisting temperature, pH, loads, phenol and Cr⁺⁶ shock, treatment effect of domestic sewage were analyzed, and biological density, distribution characteristics, distribution of microorganism dynamics of microorganism fixed in AT-PVF carrier and pollutant degradation in AI-SBR were studied. New carriers’ practicality and performance were determined. Microbial characteristics before and after carrier microbial formed were compared. Application advantage of AI-SBR weas analyzed. Main result as follows: （1） Through attapulgite nanoocomposites was mixed into PVF by ultrasonic dispersion, new immobilized microbial carriers （AT-PVF） was obtained by catalytic, crosslinking and foaming reaction. The best condition were that: PVA: 13%, formaldehyde:PVA: 0.75, H₂SO₄:PVA: 1.0, surfactant :0.5%, AT:0.4%（2） Comparied materialization and biochemical performance of AT-PVF carrier with that of sponge carriers, AT-PVF carrier’s microorganism coherence and mass transfer performance were better than sponge carrier’s. The tension strength of AT-PVF carrier was 2.38Mpa, which is 1.23 times of sponge carrier’s. The pore-size ranges were large, the homogeneous pore of AT-PVF was distributed, and the surface of AT-PVF was roughened. Under steady state conditions, the speed of biofilm cultivation was 5 days which was 2 days faster than sponge carrier’s, the removal rate of COD was 96.2% which was 6 % higher than sponge carrier’s, the removal rate of ammonia nitrogen was 95.3 % which was 7 % higher than sponge carrier’s, and the quantity of sludge was 1.25 times of sponge carrier’s.（3） Combined SBR with AT-PVF carrier, AI-SBR was formed. Comparied AI-SBR reactor with SBR reactor, the speed of starting-rate, the removal-rate of pollutants, and the shock resistance were relatively high in AI-SBR. After reactor performance 6 days and 210 days, biological density of AT-PVF carrier were15.2 mg/cm³and 44.3mg/cm³, that was 4-11 times than that of conventional activated sludge. Microorganism carrier has high bological activity, plentiful biofacies, and strong resistance to bad environment.（4） When used AT-PVF carrier in the aeration tank, a two-tier network from top to bottom must be set up. When carrier microbes withed 2-3 cm³ massive and at the filling rate of 60% were added to network, the effect was best. When used AT-PVF carrier in the SBR, Lower network was lied above aeration equipment, higher network was lied between highest water level and lowest water level and vertical network was lied in order to isolation water decanter equipment. Because net carrier microbes can play ’active intercept’, the SS concentration of effluent was low. For aeration tank, the burden of secondary sedimentation tank can be reduced, so the sedimentation tank can be omitted. For SBR reactor, precipitation stage can be shorten and omitted, so the period was shorter and the ability of SBR reactor was raised.（5） The process of formation of biofilm can be divided into two parts: reversible adhesion and irreversible adhesion. In first 30 min, reversible adhesion was occurred. When microbe and carriers contacted 40-300min, irreversible adhesion was occurred. After300min, microorganism on carriers began propagation.In reversible adhesion, the change of microbial biomass coherence on carriers with time is related by B = （?）. Among them, B_max is maximum microorganismattachment amounts in unit volume carriers, which effect the adsorption rate and attachment amounts. The large numerical is good.αis microorganism coherence constant. The large numerical is good. For AT-PVF carriers, B_max=8.23mg/cm³,α=0.04min^-1.In irreversible adhesion, The change of microbial biomass coherence on carrierswith time is related by B = （?）. Among them, B₀ is microorganism attachmentamounts in unit volume carriers at the beginning of irreversible adhesion, which effect the irreversible adsorption rate and final attachment amounts. The large numerical isgood.α’₃ is rate constant of microbial-fixed. The large numerical is good. For AT-PVF carrier, B₀=2.287mg/cm³,α’₃ =0.085min^-1。B_max ,α,B₀ andα’₃ can be used as index to measure service performance of biologicalcarrier.（6）Kinetic experiment showed that removal COD by microorganism fixed in AT-PVF carrier was accord with first-order Monod kinetic reation. At different pH and temperature, The K_COD of AI-SBR reactor was more than that of SBR reactor.Removal ammonia nitrogen by microorganism fixed in AT-PVF carrier was also accord with first-order Monod kinetic reation. The maximum degradation rates Vmax=16.581, half-saturation constant Ks=40.65mg/L in SBR. Vmax=24.078 in AI-SBR, which was 1.5 times than SBR’s. It showed that the ammonia nitrogen degradable behavior of AI-SBR was superior. Ks=22.9885mg/L in AI-SBR reactor, which was little than SBR’s. It showed that the maximum degradation rates easily attained at a low ammonia nitrogen concentration in AI-SBR.The results show that: AI-SBR which formed by adding AT-PVF carriers into SBR has high removal-rate of pollutants and the shock resistance than SBR. AT-PVF carrier had good ability of resisting temperature, pH, loads and Cr⁺⁶ shock. The intended purpose was reached.更多还原