尖针杆藻对砂滤池的堵塞过程分析及控制技术研究

发布时间：2018-03-19 12:43

本文选题：硅藻　切入点：尖针杆藻　出处：《哈尔滨工业大学》2013年硕士论文　论文类型：学位论文

【摘要】：尖针杆藻（Synedra acus KUtzing）是硅藻的一种，在自然水体中分布广泛，常在冬季和春季的低温、高溶氧、贫营养性的水体中形成单一的优势种群。水源中的尖针杆藻进入水处理系统后，会影响混凝沉淀过程，造成滤池严重堵塞。尖针杆藻在滤池的表面板结成藻类团状泥糊，直接导致反冲洗周期缩短和反冲洗耗水量呈几何级数增长。本文主要立足于解决尖针杆藻堵塞砂滤池的问题，进行了尖针杆藻堵塞砂滤池过程分析；对比研究了强化混凝沉淀、过滤截留和气浮三种不同方法对尖针杆藻的去除技术效果分析；并进行了尖针杆藻堵塞滤池的应急去除研究。研究了尖针杆藻堵塞砂滤池的现象与其本身长度和滤砂粒径的关系。滤砂粒径和尖针杆藻长度的比值R小于3时，尖针杆藻完全无法通过滤砂；R在3-6之间时，，尖针杆藻会造成滤砂严重堵塞；R在6-8之间时，尖针杆藻的堵塞情况不甚严重；R大于8时，尖针杆藻不会造成明显堵塞。正常的反冲洗过程对去除滤池内成团的尖针杆藻效果不好。对比了实验室内和实际生产过程中尖针杆藻堵塞滤池的不同现象，进一步分析了堵塞的原因。尖针杆藻自身难以沉降，加入助凝剂进行混凝沉淀可以提高对尖针杆藻的去除率。尖针杆藻的去除率随pH值升高而增大，当投加石灰4mg/L调节pH值在8时，尖针杆藻的去除率从40%上升到60%；PAC的投加量低于2mg/L时与尖针杆藻的去除率有正相关的关系，在投加量为2mg/L时去除率可达60%；HCA、PAM和藻酸钠对去除尖针杆藻都有辅助作用，相同投加量情况下HCA效果优于PAM；预氧化可以提高尖针杆藻的去除率，KMnO4、NaClO、ClO2都可以将去除率提高到90%；预氧化与助凝剂的联合使用条件下尖针杆藻去除率达可到98%。过滤截留可以去除尖针杆藻，但存在着堵塞和清洗困难的问题。200目到300目的不锈钢滤网可以对尖针杆藻实现30%-60%的截留，6小时过滤后的滤速损失在40%-60%之间。气浮可以有效快速去除尖针杆藻。混凝过程对气浮去除尖针杆藻影响较大，控制浊度、pH值和助凝剂的投加量可以在5分钟内使尖针杆藻的去除率达到88%。气浮对尖针杆藻的去除率低于混凝沉淀过程。对已经严重堵塞的砂滤池采取氧化剂浸泡和物理去除的方式可以防止成团尖针杆藻附着在滤砂表面，从而改善反冲洗对滤池内尖针杆藻的去除效果。
[Abstract]:Synedra acus Kutzingis a kind of diatom, which is widely distributed in natural water. It often forms a single dominant population in low temperature, high dissolved oxygen and poor nutrition water in winter and spring. It will affect the coagulation and sedimentation process and cause serious blockage in the filter. The algal muddy paste formed on the surface of the filter directly results in the shortening of backwashing cycle and the geometric increase of backwashing water consumption. In this paper, based on solving the problem of blocking sand filter, the process of clogging sand filter is analyzed, and the enhanced coagulant sedimentation is compared and studied. Three different methods of filtration interception and air floatation were used to analyze the technical effect of the removal of Phellodendron cuspidata, and the emergency removal of the clogged filter was studied. The relationship between the phenomenon of blocking sand filter and the length of sand filter and the diameter of sand filter is studied. The ratio R of sand filter diameter and the length of algaea cuspidata is less than 3:00, when the sand filter can not pass through the sand filter R between 3 and 6, the ratio of sand filter diameter and sand filter diameter is less than 3:00. When the filter sand clogging rate is between 6 and 8, the clogging rate is lower than 8:00. The normal backwashing process is not good for removing the agglomerated alga in the filter. The different phenomena of blocking the filter in laboratory and in actual production are compared. The causes of blockage are further analyzed. It is difficult for the alga to settle itself. Adding coagulant to coagulate and precipitate can increase the removal rate of P. cuspidata, and the removal rate increases with the increase of pH value, when the pH value is adjusted at 8:00 by adding lime 4mg / L, the removal rate of P. cuspidata can be increased with the addition of lime 4mg / L to adjust the pH value at 8:00. When the dosage of PAC was less than 2 mg / L, there was a positive correlation between the removal rate and the removal rate of P. cuspidata. When the dosage was 2 mg / L, the removal rate could be up to 60% HCAPAM and sodium alginate were helpful to the removal of Phaeopsis cuspidata. At the same dosage, the effect of HCA was better than that of pam, the removal rate of KMnO _ 4 and NaClO _ 2 could be increased to 90% by pre-oxidation, and the removal rate of alga cuspidata was up to 98% under the condition of combination of pre-oxidation and coagulant. Filtration and retention can remove Acetoderma cuspidata, but there are some problems such as clogging and cleaning difficulty. From 200 mesh to 300 mesh stainless steel filter can achieve 30% -60% loss of filtration speed after 6 hours of filtration for Phellodendron cuspidata, and the loss of filtration velocity is between 40% and 60%. Air floatation can effectively and quickly remove Acetoderma cuspidata. The coagulation process has a great influence on the removal of Phellodendron cuspidata by air floatation. Controlling the pH value of turbidity and the dosage of coagulant can make the removal rate of P. cuspidata reach 88% in 5 minutes, and the removal rate of air floatation is lower than that of coagulant sedimentation process. Using oxidant immersion and physical removal to the seriously blocked sand filter can prevent the alga from sticking to the sand filter surface, thus improving the effect of backwashing on the removal of Acetoderma cuspidata in the filter.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU991.2

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