【作者】 范振强；

【导师】 崔福义；

【作者基本信息】 哈尔滨工业大学 ， 市政工程， 2010， 博士

【摘要】 高微囊藻原水影响饮用水常规处理工艺的正常运行和产水水质。为降低常规工艺和其他除藻工艺的藻类负荷,本文提出利用鲢鱼对微囊藻的选择性滤食特性,在净水厂预沉池中放养滤食性鲢鱼的生物预处理,并自2005年开始在天津某水厂进行生产性试验。为了深入认识藻类的变化和去除规律,在种类细分的基础上对试验过程中藻类变化进行了检测。试验期间,在引滦水中共检出藻类7门43属68种。春季引滦水中绿藻占优势,藻类总量平均189.4×104cells/L;夏季水温升高,蓝藻占优势,藻类总量平均2724.8×104cells/L(最高5933×104cells/L),其中水华微囊藻是绝对优势藻,含量占藻类总量的80.9%;秋季引滦原水中绿藻重新占优势。水温是影响原水藻类群落结构变化的关键因素。鲢鱼放养密度约65g/m3的预沉池对引滦原水中藻类的去除效能受原水藻类群落结构的影响。由于鲢鱼并不能抑制绿藻含量的增长,春季放养鲢鱼的预沉池出水藻类含量高于进水2.54倍。夏季,虽然绿藻含量仍有升高,但鲢鱼对水华微囊藻平均79.5%的高效去除使出水藻类总量降低了55.3%。秋季放养鲢鱼的预沉池出水藻类含量高于进水。空白对比试验表明,预沉池放养鲢鱼是微囊藻得到控制的原因。研究发现,放养鲢鱼对预沉池中浊度降低和pH值升高并无明显影响,鲢鱼对藻类的滤食可能有助于磷的去除。根据鲢鱼放养密度修正之后,除藻效能回归方程可较为准确地预测微囊藻的去除效能。根据鲢鱼除藻机理建构的动力学模型能够量化地描述含藻原水进入预沉池之后藻类含量的变化过程。基于动力学模型的深入分析表明,在满足了适宜鲢鱼放养密度、原水中微囊藻的优势地位以及适宜的水力停留时间等条件后,预沉池利用鲢鱼的生物预处理能够获得较好的控制藻类总量的效果。预沉池利用鲢鱼的生物预处理和常规工艺联用能够充分发挥各单元的除藻特色。生物预处理适于去除微囊藻,而常规工艺各单元对其他藻类的去除效果较好。预氯化单元除藻效果稳定可靠,而混凝沉淀单元对绿藻的去除效果优于蓝藻,过滤单元对藻类的高截留率则是保证滤后水藻类低含量的关键。综上所述,净水厂预沉池利用鲢鱼的生物预处理技术不仅有稳定而良好的去除微囊藻效能和清晰的运行机制,而且不消耗电能药剂、不排放温室气体,具有广阔的推广应用前景。更多还原

【Abstract】 High concentration of Microcystis in raw water cause negative effect on the operation of conventional drinking water processes and drinking water quality. In order to reduce algae load of conventional drinking water treatment and other processes for algae removal, the biological pretreatment of algae-laden raw water by stocking filter-feeding silver carp was proposed in waterworks. Since 2005 the experiment was conducted in the presedimentation tank in a waterworks in Tianjin.Algae species in raw water were identified to comprehensively understand the algae changes and removal characteristics. 7 phyla, 43 classes, 68 species of algae was determined based on the analysis on the phytoplankton community structures in Yinluan raw water. In spring green algae was the predominant species in Yinluan raw water, and the mean value of algae concentration was 189.4×104cells/L, while in summer cyanobacteria was the predominant species, and the mean value of algae concentration was 2724.8×104cells/L (the highest value was 5933×104cells/L). In summer Microsystis flos-aquae had very high proportion of 80.9% in the raw water. In autumn green algae became the predominant species again. Water temperature is key factor that influences the phytoplankton community structure.After silver carp were stocked in the presedimentation tank at the density of 65g/m3, phytoplankton community structure had remarkable influence on removal efficacy of algae in Yinluan raw water. Because silver carp cannot inhibit the growth of green algae, the algae concentration were 2.54 times more in effluent than in influent. Although in summer the concentration of green algae rose, the algae removal reached to 55.3% due to the effective removal of Microsystis flos-aquae by silver carp. However in autumn the algae concentration were more in influent than in effluent. Contast test indicated that stocking silver carp led to the effective removal of Microsystis flos-aquae. It was also found that silver carp stocking had not remarkable influence on turbidity and pH in the presedimentation tank, and the silver carp filter-feeding on algae may contribute to the transfer and removal of phosphorus.Revised regression equations of algae removal efficacy could accurately predict the Microsystis flos-aquae removal efficacy, and the kinetic model was able to clearly describe the mechanisms of the change of algae in the presedimentation tank stocked by silver carp. Kinetic model analysis showed that enough stocking density of silver carp, dominance of Microcystis in influent and suitable HRT makes the biological pretreatment of utilizing silver in presedimentation tank possible.Algae removal characteristics can be fully played when the biological pretreatment of stocking silver carp in presedimentation tank and conventional processes are combined. The biological pretreatment is suitable for Microsystis flos-aquae removal, and conventional processes can effectively remove other algae. Algae removal of prechlorination unit are stable and reliable, while the coagulation-sedimentation units have a better removal for green algae than cyanobacteria, and the high filter rate of algae is important to ensure low-level algae concentration in water.In summary, the biological pretreatment technology of stocking silver carp in presedimentation tank not only has a stable and good Microcystis removal performance and clear operation mechanism, also has the advantages of no energy and chemicals consumption, no greenhouse gas emissions, and has a bright future of practical application.更多还原