光生物反应器中市政污水培养钝顶螺旋藻的条件优化

发布时间：2018-06-26 05:19

本文选题：钝顶螺旋藻 + 光生物反应器　；参考：《江南大学》2017年硕士论文

【摘要】：微藻分布十分广泛,其光合效率高、繁殖速度快、环境适应能力强。微藻培养过程中需消耗大量的水资源和碳、氮、磷等营养盐,使其规模化生产成本较高。利用污水培养微藻,能够回收利用污水中氮磷等营养元素,获得微藻生物质并实现污水净化,具有较高的经济、社会和环境效益。本文选择经济价值高、环境适应能力强的钝顶螺旋藻为研究对象,以市政污水为螺旋藻培养液,以PBR和MPBR为螺旋藻培养和分离的反应器,探究市政污水培养钝顶螺旋藻的适宜条件。为提高螺旋藻生物量,对碳源、HRT、藻密度等培养条件以及批次、半连续、连续的培养方式进行优化调整;同时为延长膜使用寿命,在分析膜污染物质的基础上确定适宜膜孔径和膜清洗方法;最后,通过实验数据和动力学方法分析比较PBR与MPBR的运行效果。本文的主要研究结果如下:(1)市政污水添加0.80 g/LNaHCO_3能够用于螺旋藻的培养。(2)锥形瓶中批次培养螺旋藻至第12天生物量最高,为1.51g/L。(3)PBR连续培养螺旋藻时,确定适宜HRT为20 d,反应器中藻密度维持在1.00g/L-1.20 g/L。采收螺旋藻生物量为0.42 g/d,污水进水量为0.35L/d。不同HRT下螺旋藻对氮、磷营养盐的去除效果相似,NH_4~+-N、TN、TP去除率分别为98.52%-99.03%、90.43%-95.22%、88.25%-96.81%,出水NH_4~+-N、TN、TP浓度均达到《国家城镇污水处理厂污染物排放标准》(GB18918-2002)一级A排放标准。(4)MPBR半连续培养螺旋藻时,确定最短HRT为1.75d,反应器中螺旋藻密度约为1.80 g/L-2.00 g/L。MPBR连续培养螺旋藻时,HRT为1.75 d、MRT为20d时,采收螺旋藻生物量为0.69 g/d,污水中藻细胞的蛋白质、碳水化合物和叶绿素a含量等细胞组分与培养基中藻细胞的相近。污水进水量为4 L/d,NH_4~+-N、TN、TP、COD的去除率分别为93.54%-98.97%、77.06%-90.24%、48.37%-66.91%和23.37%-47.28%,出水NH_4~+-N、TN浓度达到一级A标准,TP浓度达到一级B标准,出水中多种金属离子含量均低于进水。污水中约93.15%的N元素、95.57%的P元素被螺旋藻吸收利用,转化为自身细胞的组成物质。(5)EEM、SEM和EDX分析膜面污染物结果显示,进水膜面主要是EOM等有机物形成的滤饼层污染,出水膜面附着含Ca为主的无机沉淀物,部分膜孔径堵塞。过滤藻液时适宜的膜孔径为0.45μm;膜清洗方法为将污染膜片超声振荡0.50 h,再先后利用pH值为2的盐酸和200mg/LNaClO溶液浸泡清洗2h,清洗后纯水通量恢复为初始纯水通量的94.29%。(6)市政污水培养螺旋藻过程中,与PBR相比MPBR能耗和成本较高,但MPBR能够明显提高藻密度和污水负荷,反应器操作条件更灵活、运行更稳定。实验结果表明,MPBR中螺旋藻密度约为PBR的2倍,采收量从0.42g/d提高至0.69g/d;HRT显著缩短,污水进水量是PBR的11倍,进水N负荷从7.70 mg/d-8.05 mg/d提高至122.28mg/d-137.96mg/d,进水P负荷从0.44mg/d-0.50 mg/d提高至7.57 mg/d-8.21 mg/d;MPBR中去除N、P的量分别为PBR的14-15倍、9-11倍。动力学分析从理论上表明MPBR应用于螺旋藻培养方面的有效性。
[Abstract]:Microalgae are widely distributed, with high photosynthetic efficiency, rapid reproduction rate and strong environmental adaptability. In the process of microalgae culture, a large amount of water resources and nutrients such as carbon, nitrogen and phosphorus are consumed, which makes the production cost of microalgae on a large scale higher. Using sewage to cultivate microalgae can recover nutrient elements such as nitrogen and phosphorus in sewage, obtain microalgae biomass and realize sewage purification, which has higher economic, social and environmental benefits. In this paper, Spirulina platensis with high economic value and strong adaptability to environment was selected as the research object. The municipal sewage was used as the culture medium of spirulina, and PBR and MPBR were used as the reactors for the culture and separation of spirulina. To explore the suitable conditions for the cultivation of Spirulina platensis by municipal sewage. In order to improve the biomass of Spirulina platensis, the culture conditions such as carbon source HRT, algal density, batch, semi-continuous and continuous culture methods were optimized and adjusted to prolong the service life of the membrane. Based on the analysis of membrane fouling materials, the suitable membrane pore size and membrane cleaning method were determined. Finally, the operation effects of PBR and MPBR were analyzed and compared by means of experimental data and kinetic method. The main results are as follows: (1) municipal sewage added 0.80 g / L NaHCO3 can be used in the culture of spirulina. (2) the biomass of spirulina cultured in conical flask was the highest up to the 12th day, which was 1.51g / L. (3) when PBR was used to culture spirulina continuously, The optimum HRT was 20 days and the algae density in the reactor was maintained at 1.00 g / L ~ (-1) g 路L ~ (-1) 路L ~ (-1). The biomass of Spirulina was 0.42 g / d and the influent of sewage was 0.35 L / d. The removal rates of nitrogen and phosphorus nutrients of Spirulina platensis under different HRT conditions were 98.52- 99.03and 90.43- 95.2222and 88.25- 96.81respectively, the removal efficiency of NH4- NnnnTTP was 98.52- 99.030.The effluent NH _ 4~ -NTN _ (TNN) TP concentration reached the first A discharge standard (GB18918-2002). (4) when the spirulina was cultured semi-continuously with MPBR, the effluent NH4- ~ -NN _ (TNN) _ (TP) reached the first class A discharge standard (GB18918-2002). The shortest HRT was 1.75 days, the density of spirulina was about 1.80 g / L ~ (-2.00) g / L ~ (MPBR) in the reactor, when the HRT was 1.75 d ~ (-1) MRT was 20 days, the biomass of Spirulina was 0.69 g / d, and the protein of algae cells in sewage was obtained. The contents of carbohydrates and chlorophyll a were similar to those of algal cells in culture medium. The removal rate of TPCOD in effluent was 93.54-98.97 and 77.06-90.2424It was 48.37-66.91% and 23.37-47.28.1%, respectively. The effluent NH _ 4~ -NN _ N _ (TN) concentration reached the first A standard TP standard, and the content of many metal ions in the effluent was lower than that in the influent. About 93.15% of N elements in sewage were absorbed by spirulina and converted into components of its own cells. (5) the results of EEMU SEM and edX analysis showed that the main fouling of the influent membrane was the filter cake layer formed by organic compounds such as EOM. Inorganic precipitates containing Ca were attached to the surface of the membrane, and some of the pore sizes of the membrane were blocked. The optimum membrane pore size is 0.45 渭 m when the algae solution is filtered, the membrane cleaning method is to oscillate the contaminated membrane by ultrasonic for 0.50 h, then soak and clean the membrane with pH 2 hydrochloric acid and 200 mg / L NaClO solution for 2 h, and the pure water flux is recovered to 94.29% of the original pure water flux after cleaning. (6) In the process of cultivation of spirulina by sewage, Compared with PBR, MPBR has higher energy consumption and higher cost, but MPBR can significantly increase algae density and sewage load, and the operation conditions of the reactor are more flexible and stable. The experimental results showed that the density of Spirulina in MPBR was about 2 times of that of PBR, the yield of Spirulina was increased from 0.42g/d to 0.69 g / d HRT, and the water intake was 11 times higher than that of PBR. The N load of influent increased from 7.70 mg/d-8.05 mg/d to 122.28 mg / d-137.96 mg / d, and the amount of N P removed from 0.44mg/d-0.50 mg/d to 7.57 mg / d was 14-15 times and 9-11 times of that of 0.44mg/d-0.50 mg/d, respectively. The kinetic analysis showed that MPBR was effective in the culture of Spirulina platensis.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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