【作者】 郑蓓；

【导师】 林进； 葛小鹏；

【作者基本信息】 河北师范大学 ， 有机化学， 2010， 硕士

【摘要】 接触絮凝是一种新型的水处理工艺技术原理与方法,微絮凝-直接过滤作为接触絮凝的代表性工艺,在水处理实践中具有广泛的应用前景。论文以接触絮凝工艺技术原理与开发应用为主要研究目标,首先对絮凝的有关基础理论与发展现状,絮凝剂的发展概况,以及接触絮凝工艺的应用进展情况进行了文献综述,并围绕以下几方面问题进行了全面系统的实验研究:1.絮凝剂是接触絮凝工艺的重要构成要素,其性能优劣直接影响到整体工艺的处理效果。因此对絮凝剂的形态组成及其作用机理进行深入研究具有重要意义。论文首先对碱化度及铝的不同聚合形态对絮凝效果的影响进行了实验研究,通过烧杯混凝实验对絮凝剂进行优化筛选,并对高效聚合氯化铝的最优絮凝效果进行了实验验证。2.低温低浊水体由于水的粘度大、颗粒物含量少,絮凝剂投加到水体后絮凝反应慢,生成的絮体(矾花)小、不易沉降,且极易穿透滤层等因素影响,一直是给水厂处理的难点。论文通过两个低温低浊水体处理的具体实例,对接触絮凝工艺技术的应用进行了深入研究。通过投加少量石英砂,人为增加水体浊度这一强化手段,对新疆额尔齐斯河低温低浊水体进行接触絮凝试验研究,并优化了反应条件;以微絮凝-直接过滤工艺对北京市某水厂冬季沉淀池出水进行接触絮凝过滤实验研究,通过絮凝剂的筛选及滤料粒径的优化,对混凝及过滤过程进行协同与强化,提高滤床的截污能力,优化了整体工艺运行参数。3.应用接触絮凝工艺对东江流域典型印染废水毒害污染物的削减与水质回用进行了实验研究。以微絮凝-直接过滤以及混凝-沉淀-多介质过滤等工艺技术,对东江流域典型印染企业尾水进行深度处理,并进行水质回用适应性研究;通过纳米铁复合投加强化措施,以混凝-沉淀-多介质过滤工艺对印染尾水有机污染物的降解去除进行了实验研究。根据以上的实验研究主要得出了以下几点结论:1.高盐基度的聚合氯化铝的絮凝效果要优于低盐基度的聚合氯化铝;高Alb含量聚合铝形成的絮体较为松散不易沉淀,高Alc含量聚合铝形成的絮体密实易于沉淀分离且对有机物和颗粒物的去除效果较好;絮凝剂高效聚合氯化铝(HPAC)的絮凝效果要优于普通聚合氯化铝(PACl)。2.针对低温低浊水体处理来讲,较优的絮凝工艺条件是:慢速反应时间T值,以20-25min为宜,慢速反应搅拌强度G值可采用30S-1。人为增加浊度实验表明:在低温低浊水体的絮凝过程中投加SiO2可以增大颗粒物之间的碰撞几率,改善絮凝效果,但不宜投加过多,否则会增加出水浊度。当采用接触絮凝工艺对其进行处理时比传统的水处理工艺有效地改善了出水水质。3.经实验研究表明,接触絮凝工艺中的代表工艺-微絮凝-直接过滤可以有效地使印染企业尾水达到回用标准。其中,当使用多介质过滤工艺时的处理效果要好于匀介质过滤工艺;在絮凝剂选择方面,高效聚合氯化铝的处理效果要好于传统的硫酸亚铁和聚合氯化铝。论文针对印染废水的毒害污染削减的问题研究出一种新型的尾水深度处理工艺——纳米铁+混凝-沉淀-多介质过滤工艺。通过实验证实,该工艺用于对印染企业尾水进行毒害物质削减是可行的。絮凝剂选用新型高效絮凝剂HPAC-9可以使处理效果更佳。纳米铁的引入是这一工艺的创新点,少量纳米铁的存在,强化了水体有机污染物的降解及混凝协同去除。但是由于纳米铁活性较高故而投加量不宜过大,否则会使得尾水的有机污染物进一步降解,形成转化产物;而且,由于Fe2+的缓慢氧化,处理出水静置一段时间后,有可能导致水体变色,呈现铁离子的颜色。更多还原

【Abstract】 Contact flocculation technology with micro-flocculation– filtration as a representative process has found wide application in both water and wastewater treatment practice, which is promising to provide a new fundamental principle of separation technology in water treatment processes.This thesis aims at the development and application of contact flocculation process in water treatment technology. The basic theory of coagulation and flocculation and its recent development in polymeric flocculants of hydroxyl ployaluminum (PACl) in both the interaction mechanisms and the suitable applied technology are reviewed in the paper based on the literature survey. Comprehensive and systematic experimental study is then conducted, which is mainly focused on the following aspects:1. As an important buildup element of contact flocculation process, the speciation and distribution of hydroxyl polymeric aluminum flocculants play a significant role in the overall process performance. Therefore, the study of aluminum polymer species and their interacting mechanism is of great concern. In the first part of the thesis, the effects of basicity and different aluminum polymer species on the coagulation performance of PACl coagulants are carried out by jar test to screen out the optimized PACl flocculants with high efficiency for the contact flocculation process of micro-flocculation– filtration technology.2. Treatment of drinking water with low temperature and low turbidity is proved to be a tough task due to its high viscosity, less particulates, slow coagulation rate after dosing the flocculants, and the small flocs (alum) that are usually formed in the coagulation process are hard to settle down, causing them easy to penetrate through the filter layers in the filtration bed. In the second part of this paper, two cases of study in the drinking water treatment with low-temperature and low turbidity are experimentally performed using contact flocculation technology. By dosing a small amount of quartz sand to the raw water from the Irtysh River in Xinjiang to artificially increase the turbidity for the enhancement of coagulation performance, experiments are carried out in pilot-scale to optimize the contact flocculation reaction conditions; In the second case study, water samples with low temperature and low turbidity from the settling tank of water plant during the winter in Beijing were investigated using both the conventional and enhanced filtration process. Based on the head loss, particle counts, TOC and COD, conditions of PACl dosage, particle size of filter medium, and the coagulation time etc. of the micro-flocculation and enhanced filtration process are screened out in order to improve sewage interception capabilities of the filter bed, and to optimize the operating parameters of the overall process performance .3. To demonstrate the applicability of contact flocculation technology in the advanced treatment of typical dye printing wastewater effluents downstream in the Dongjiang river basin, both the micro-flocculation / direct filtration and the Coagulation - Precipitation - Multi-media filtration processes are investigated on the tailing wastewater discharged from a local bleaching and dyeing mill of textile industry for the purpose of water reuse and pollutants emission reduction. Jar test is performed on the dye printing wastewater effluents to optimize the coagulation conditions in the micro-flocculation / direct filtration combined process and through the dosing of the composite coadulants nano iron is introduced as an aid into the Coagulation - Precipitation - Multi-media filtration process to enhance the removal of organic pollutants for their emission reduction.The following conclusions have been reached based on the above experimental results:1. PACl with high alkalinity is usually demonstrated better coagulation performance than that with the low one; High-Alb content PACl flocculants are easy to form loose flocs to be difficult to settle down for separation, while PACl with high-level Alc often leads to compact flocs that facilitate the removal of organics and particulates by the precipitation process of flocs; HPAC flocculants are proved to be superior to the ordinary PACl coagulants in the performance.2. For the treatment of raw water with low temperature and low turbidity, optimized coagulation conditions are as follows: 20-25 min for the slow agitation reaction time(T) with 30 S-1of velocity gradient (G). The introduction of small amounts of silica particles into the low temperature and low turbidity water body can largely improve the coagulation performance due to the increase of collision efficiencies between the aquatic particles, but dosing of SiO2 particles should be precisely controlled in a small quantity, otherwise it will deteriorate the effluent water quality due to a poor residual turbidity removal. It is concluded that compared to the conventional water treatment technology micro-flocculation /direct filtration process can effectively improve the water quality in the drinking water treatment with low temperature and low turbidity3. Micro-flocculation - direct filtration, which is a representative technology of contact flocculation process, can be successfully exploited in the advanced treatment of typical dye printing wastewater effluents for the purpose of water reuse and pollutants emission reduction. The effluents by micro-flocculation - direct filtration process can meet the urban recycling water quality standard for industrial use (GB/T19923-2005), in which better results can be obtained in the multi-media filtration than that in the uniform media process; In the selection of coagulants, HPAC is better than conventional ferrous sulfate and PACl in the overall process performance. Furthermore, a novel advanced treatment process, i.e. nanoscale iron + coagulation - precipitation - Multi-media filtration, has been investigated on the dye printing wastewater to reduce the emission of toxic pollutants. The selection of high-efficient flocculants in the serious products of HPAC-9 can offer better treatment results. Dosing of a small amount of nano-iron is the key point for this process, which may facilitate the degradation of organic pollutants in wastewater and enhance the overall removal of organics by combined processes, and therefore reduce the emission of the toxic pollutants into the water body. Nevertheless, the dosage of nano- iron should not be large due to its high reactivity, otherwise small molecular weight degradation products of organic pollutants may be formed, which may complicate the performance of organic removal by the combined processes; Moreover, the slow oxidation of Fe2 + residual in the effluents may cause a color change of the effluent water when preserved for some time.更多还原