【作者】 张刚；

【导师】 黄廷林；

【作者基本信息】 西安建筑科技大学 ， 市政工程， 2010， 博士

【摘要】 当前,水处理工艺的设备化,小型化已经成为水处理技术的一种发展趋势。结团絮凝工艺作为一种新型高效固液分离水处理工艺,已成为水处理工艺设备化,小型化的一种理想选择。结团絮凝工艺研究在技术原理、工艺控制条件及反应器设计等方面已取得了丰硕的成果,然而在工艺优化、结团絮体成长、结团体悬浮层动力学等方面的研究尚不够深入。本文以结团絮凝工艺优化与结团絮体悬浮层为研究对象,对悬浮层布水区及搅拌条件,以及微絮凝条件进行了优化设计,建立了悬浮层中结团体成长模型,并以天津杨柳青水厂排泥水为处理对象进行了试验验证,在此基础上对工艺条件进行了优化,并对低原水浓度条件下工艺的运行方式进行了探讨。最后,通过生产性试验对研究成果进行了验证。论文成果主要包括以下方面：(1)进一步优化了结团絮凝反应器构造及微絮体形成控制条件根据悬浮层布水隔板水力计算,为保证配水均匀以及药剂与原水的均匀混合,将配水过流断面设计为楔形；为保证搅拌G值均匀输出,经优化计算,搅拌桨宽度应沿径向按B=Cr-3逐渐减小,并分别对小型和大型搅拌桨进行了优化设计及G值校核计算；试验条件下,选择管式反应器作为微絮凝反应器,确定(G/Re)0.5T值为10.87的管式反应器与结团絮凝工艺组合处理效果最佳。(2)建立了结团絮体成长动力学模型通过研究结团体所受剪切力及相互之间的碰撞频率,对结团体有效密度ρe的影响因素分析表明,悬浮层体积浓度Vf和G值均与ρe成正比关系；研究了工艺条件对ρe的影响规律,认为原水浓度CO及上升流速uw的变化会引起结团体ρe或结团体粒径d的显著变化；通过分析结团体在悬浮层中的受力情况,建立了结团体成长粒径表达式d=(?)及最小粒径的表达式dmin=0.038(?)；基于物(?)料平衡方程,通过分析结团体成长中粒径的变化建立了体积浓度变化的微分方程：模型验证结果表明,模型具有较好的适用性；基于结团体生长模型建立了最大上升流速流速与原水浓度间的负线性关系。(3)优化了结团絮凝工艺运行条件引入搅拌G值将结团絮凝基本公式修正为C=C0exp(?),通过对结uw团体悬浮层的动力学分析得出了结团体悬浮层适宜的上升流速应介于最小上升流速uwmin=0.004(?)d及达到浊度限值的上升流速uw=(?)之间通过工艺运行条件优化的中试试验验证了上述理论,同时优化了工艺运行参数。(4)确定了污泥回流条件下低原水浓度的结团絮凝工艺控制条件确定最佳污泥回流点设置于PAM投加点之后,反应器进水口之前；污泥回流条件下,随着回流比的增大,出水浊度的变化表现为先降低,后稍有上升趋势,而试验数据表明,回流比的增大有助于结团体沉降性能的提高；通过对结团体悬浮层中初始粒子的去除规律研究建立了最佳污泥回流量的控制条件：(?)(5)完成了工艺运行的生产性试验研究建设了天津杨柳青水厂排泥水结团絮凝工艺处理的生产性试验系统,并优化确定了系统的运行控制条件。在PAM投量为1.2mg/L,搅拌转速为2-4rpm的控制条件下,水流上升流速可达22.1cm/min-66.4cm/min；上升流速提高,出水浊度呈增大趋势,但均小于14.9NTU；排泥含水率可低于96%,且运行稳定,受季节变化影响小。设计并建成了该工艺的自动控制系统。该系统实现了在进水浊度及流量变化情况下能及时通过调整加药量稳定出水浊度,并实现自动排泥；成本核算结果表明,在30m3/h的处理规模下,年运行成本4.42万元,吨水处理成本0.17元。工程的具有较为显著的社会效益、环境效益和经济效益。更多还原

【Abstract】 Accompany with the development of water treatment technology, the treatment process tend to miniaturization with more equipment devices. The pellet flocculation blanket(PFB) process which is characterized with high surface-loading, short residence time, small occupation area, easy erecting, flexible and wider applicability, and easy to enforce auto control, is maturing into an ideal choice of moden water treatment process. Most foregone pellet flocculation researches focused on the flocculation mechanism, the process operational conditions, the reactor designation, et al., but there leaves something to be desired in many aspects such as the optimization of operational conditions, the growth of pellet flocs, and the kinetic of pellet blanket, large numbers of researches must be done to perfect the pellet flocculation theory.This paper focused on the optimization of the process designation such as the blanket water distribution system, the agitating peddles, and the choice of pre-coagulation process, the establishment of the pellets growth model which was proved by subsequent pilot scale experiment, the effect of operational conditions on blanket characteristics, and the operation mode under low influent concentration. At the end of the investigation, theoretical results were identified through full scall experiment. The major achievements in this paper were expressed as following:(1) The optimization of the process designationIn this investigation, hydrolic calculation was applied to optimize the designation of raw water distribution system and the blanket agitator. The optimization results indicated that, to achieve well distributed water distribution, the orifice diameter or narrow slit width should declined gradually along with the downward direction. In the designation, the wetted cross-section was designed with cuniform sharp to generate microscale eddies. The hydrolic calculation of rotating agitator illustrated that, the width of agitator should declined gradually among the paddle radius derection according to the relationship of B=Cr-3, based on this theory, paddles fit for small scale and large scall reactors were designed respectively. Optimizing experiment indicated that, tubular coagulator with (G/Re)0.5T value of 10.87 achieved best results, so in this investigation, this kind of mixer was selected as the pre-coagulation device.(2) The establishment of pellet flocs growth modelIn this paper, by deducing collide frequency between pellet particles, effect factors to pellets effective densityρe was analyzed, the results indicated that, both the volume concentration Vf and the G value appeared direct proportional relationship withρe.Relevant experimental results identified these relationships. By analyzing forces act on the pellet, expression about pellet size was established as d=uw/2 (?) Kρe3(1-Vf)m , as well as the minimum size could be expressed as dmin=0.038μ(?)uw/2. Based onρe(?) the mass balance equation, the variation of Vf in an infinitesimal blanket was expressed by analyzing pellets growth in the blanket with height of dh, the relationship could beThe statistics analysis of the verification experiment indicated that, correlated experimental results could fit the model preferably, from which could achieve the calculation of blanket height.(3) The optimization of the PFB processBy considering G value, the basic eqation of pellet coagulation could be deduced as C= C0 exp(?);By kinetic analyzing of the flocs blanket, the minimum uw up-flow rate of the blanket could be established as uwmin=(?), as well as (?) the maximun upflow rate as uw=(?). The fit up-flow rate is in the interval between the minimun up-flow rate and the maximum value.The related pilot experiment identified above theories, as well as optimized the operational conditions. (4) The determination of operational conditions under low influent concentration with sludge recycleThis part of investigation is to determine optimal operational mode under low influent concentration. The pilot scale experimental results indicated that, the optimal position for sludge recycle located behind PAM dosage position and in front of the inlet, and along with the increasing of the sludge reflux ratio, effluent turbidity tend to decrease at first, and then increase. The experimental results also expressed that, the increasing of sludge reflux ratio contributed to the improvement of pellets sedimentability.The kinetic investigation about primary partical removing indicated that, under a certain operational condition, there exists optimal influent concentration under which could achieve lowest outlet turbidity; according to this thoery, the optimal sludge recycle rate could be expressed as:(5) Full scale experiment of PFB processAt the end of this paper, PFB process was applied to concentrate ferric flocs sludge in Tianjin Yangliuqing water treatment plant to inspect the applicability of theoretical results in this investigation. The full scale experimental results indicated that, by applying PFB process, under experimental condition of PAM dosage of 1.2 mg/L, agitating rotation velocity of 2-4 rpm, effluent turbidity, sludge moisture content and maximal upflow rate could be less than 10NTU, below 96% and 66.4 cm/min respectively with inlet SS ranged between 108 mg/L and 195 mg/LThe development and debugging of automatic control system supported by demonstration project was executed after the full-scale experiment. The collected data from the automatic controlled continuous running system indicated that, the control system could alter PAM dosage to the fitful value automaticly according to the change of inlet flow rate or raw water concentration, and could calculate the accumulative thicken sludge weight automatically according to the raw water concentration and inlet flow rate to achieve automaticsludge drainage.The cost-effectiveness analysis indicated that, under the experimental scale of 30m3/h, the operation cost per ton raw water is￥0.17, the annual running cost of the demonstration project is Y44200, and according to current situation of DWTP residues treatment development, the integrated high efficient treatment process developed in this project could provide high value of application and dissemination, the application of the technology could achieve obviously economic, social, and environmental benefit.更多还原