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用于市政废水除磷处理的高效絮凝剂研究
Research on High Efficiency Flocculant for the Phosphorus Removal in Municipal Wastewater
【作者】 张海彦;
【导师】 ?忱?;
【作者基本信息】 重庆大学 , 环境科学, 2004, 硕士
【摘要】 水体富营养化是目前我国较突出的环境问题之一,如何处理、再利用富营养化水体是水处理过程中刻不容缓的任务。我国新颁布的《污水综合排放标准》(GB8978-1996)要求污水厂出水磷的含量分别小于0.5mg/l和1.0mg/l。 在现有的除磷方法中,主要有化学法与生物法两种。生物法对低浓度磷处理基本能达到排放标准,但对高浓度磷处理很难达到排放标准,另外生物法除磷还存在二次污染的问题;而化学除磷法能可靠有效地去除磷,具有除磷效果较好、运行稳定、又能保证出水水质的优点。 在我国应用化学除磷的主要问题是药剂价格昂贵、运行费用较高且化学污泥量大。本实验选择廉价的铝酸钙作为原料合成絮凝剂,引入铁以降低化学污泥的产生量;引入有机高分子进一步提高絮凝剂的除磷综合性能。 实验以工业废渣铝酸钙为基本原料,添加氯化铁和聚二甲基二烯丙基氯化铵,通过酸溶、共聚和复合三步反应,合成了一种无机/有机高分子除磷絮凝剂PAFC-PDMDAAC。通过实验确定了制备PAFC-PDMDAAC的最佳工艺条件,并对PAFC-PDMDAAC的除磷性能进行了研究。实验研究内容主要包括:PAFC的制备、PAFC-PDMDAAC的制备、PAFC-PDMDAAC的絮凝性能评价、以及PAFC-PDMDAAC的应用研究。 实验结果表明: PAFC最佳合成条件为:1g铝酸钙加入6ml 20%盐酸及适量蒸馏水,控制反应温度100℃,反应3小时,合成低聚铝。并控制[Al_Υ,Fe_Υ]为0.5mol/L,[Al_Υ]/[Fe_Υ]为7:3,缓慢滴加0.025mol碱聚合,熟化24h后得除磷絮凝剂PAFC。PAFC为红棕色液体,有较好的稳定性。 PDMDAAC本身的除磷效果不明显,PAFC和PDMDAAC复配后的除浊效果优于PAFC,且处理后废水的pH值变化平稳,pH值保持在7左右。PAFC-PDMDAAC的有效pH值范围为6.5~10;PAFC-PDMDAAC对温度的适应性强,在5℃、25℃和35℃时除磷曲线集中;PAFC-PDMDAAC的搅拌条件为:先以200 r/min速度搅拌3分钟,然后以60 r/min的速度慢搅10分钟;PAFC-PDMDAAC的絮凝沉降速度快,在15分钟后几乎沉降完全。实验表明PAFC和PDMDAAC复配后提高了除磷综合性能。 对于磷含量为5.4 mg/L的实际生活污水,PAFC和PAFC-PDMDAAC除磷效果都能达到国家《污水综合排放标准》中磷排放的一级标准(0.5mg/L),同时具有污泥量少,污水pH值变化稳定的优势,但PAFC-PDMDAAC的综合絮凝除磷重庆大学硕士学位论文中文摘要性能更优于队FC。 PAFC一PDMDAAC不但除磷效果好,并克服了传统絮凝剂除磷污泥量产生大、处理前后污水pH值发生波动等不足,具有很好的实际应用意义。
【Abstract】 Eutrophication in water body is one of the most serious environmental problems to be solved in China. As a hot spot in research, treatment and reusing of eutrophic water has been paid close attention to in recent years. In GB8978-1996, maximum amount of phosphor in discharge water is 0.50mg/L and l.0mg/L respectively.Phosphorus removal technology can be divided into chemical system and biologic system. Biologic system is applicable in low phosphorus concentration wastewater with about 70% phosphorus removal. But phosphorus removed in biologic system can be liberated again and secondary pollution will be produced. Through chemical system, phosphorus can be removed steadily with simple operating steps. Up to now, chemical system is the accepted effective technology, which can remove phosphorus from wastewater with ideal and steady efficiency at the same time.There are still some shortages in the application of chemical phosphorus removal system such as expensive chemicals, high operating cost and the production of a large quantity of sludge. In this research, flocculants based on calcium aluminate have been synthesized, within which, introduction of ferrum can reduce the amount of sludge and introduction of organic high polymers can improve its phosphorus removal ability.Raw materials in this research are calcium aluminate, which is a kind of industrial waste, ferric chloride and poly dimethyldiallylammonium chloride (PDMDAAC). Through acid liquefaction, copolymerization and recombination, an inorganic/organic flocculant of PAC-PDMDAAC has been produced. Optimization preparation method of this kind of flocculant has been determined and its phosphorus removal ability has been studied. Experiments in this research including: preparation of PAFC, preparation of inorganic/organic flocculant, study of the flocculating capabilities of PAFC-PDMDAAC and study of the application of PAFC-PDMDAAC.The results of the experiments are listed below:Optimization preparation conditions of PAFC are: l.0g calcium aluminate, 6.0 ml 20% HC1 and measured distilled water, reaction temperature is 100 C, reaction time is 3h and low polymer of calcium aluminate can be produced. Dosage of [Aly, Fe ] is O.Smol/L, [AlT]/[FeT] is 7:3, 0.025mol alkali is added slowly and ageing timeof the reaction system is 24h. PAFC can be produced, which is a kind of brown liquid with ideal stability.PDMDAAC has no apparent phosphorus removal ability; recombination of PAFC and PDMDAAC can improve its phosphorus removal ability; through the recombination of PAPC and PDMDAAC, turbidity removing ability is better than PAFC itself. After the treatment by PAFC-PDMDAAC, pH value of wastewater is steady, which is about 7.0. Applicable pH value range of PAFC-PDMDAAC is 6.5-10.0; temperature flexibility of PAFC-PDMDAAC is ideal, with no obvious difference at 5 C, 25 C and 35 C. Stirring condition of PAFC-PDMDAAC is 200r/min for 3min and 60r/min for lOmin. Sedimentation velocity of PAFC-PDMDAAC is fast and completely sedimentation of these two fiocculants will take 15min.In the treatment of real municipal wastewater, phosphorus removal can meet the discharging standard I in China (GB8978-1996)-not more than 0.50mg/L. At the same time, sludge produced in this process can be reduced and pH value of wastewater has no obvious fluctuation. PAFC-PDMDAAC has better phosphorus removing ability than PAFC.PAFC and PAFC-PDMDAAC has ideal phosphorus removing ability and overcome some shortages of traditional flocculants such as high production of sludge and pH value fluctuation. These two kinds of flocculants have practicability in wastewater treatment.
【Key words】 phosphorus removal; flocculants; poly-aluminum-Ferric-chloride; poly dimethyldiallylammonium chloride;
- 【网络出版投稿人】 重庆大学 【网络出版年期】2005年 01期
- 【分类号】X703
- 【被引频次】11
- 【下载频次】915