微生物复合及固定化处理景观水体污染的研究

发布时间：2018-07-18 13:01

【摘要】：景观水在城市建设中起着画龙点睛的作用,但由于其水域面积小、流动性差和自净能力不足等特点,更易产生富营养化等污染。目前普遍使用的景观水处理方法是生物法,而微生物处理方法是当前国内外迅速兴起的一种高效率、低成本的景观水处理方法。已知枯草芽孢杆菌在好氧条件下可以将大分子有机物分解为简单有机物为好氧反硝化细菌提供还原硝酸盐所需的碳源和氮源,而光合细菌在厌氧条件下又可以将水中剩余的氨氮去除,所以本研究首先利用三种高效微生物进行了分阶段顺序处理,为进一步提高污染物去除率,又将这三种菌复合固定化,从而探索了一种能有效用于微污染景观水处理的方法。本研究从自然环境中分离并筛选出能够有效和针对性去除水体污染物的微生物,根据不同环境因素对去除能力的影响,确定了最优环境条件；为了进一步提高净化效果,在好氧条件下接种枯草芽孢杆菌和好氧反硝化细菌,待水体中的大分子物质降解后再于厌氧条件下加入光合细菌去除氨氮；然后将三种不同微生物进行两菌株和三菌株的组合,以探索复合微生物对实际景观水体污染物的去除效果。同时,为了延长微生物在污染物去除过程中的作用时间,并保持较高的降解活性,利用聚乙烯醇(PVA)和海藻酸钠(SA)对微生物进行了包埋固定化,将固定化后的好氧微生物小球投入采集的实际景观水体中,振荡培养一段时间后加入厌氧微生物小球静置培养,以研究固定化微生物小球对实际污染水体中污染物的去除作用。全文的主要结论如下：1、三种高效优势菌的筛选与菌种鉴定从自然界中分离、筛选并经分子生物学鉴定分析,确定三种高效优势菌分别为：沼泽红假单胞菌(Psb2),施氏假单胞菌(D-3)和枯草芽孢杆菌(K-9)。2、三种高效优势菌对模拟水体污染物的去除效果菌株Psb2对五种不同景观水体中氨氮的去除率在35%-95.88%之间,说明Psb2能够高效去除景观水体中的氨氮。菌株D-3接种至反硝化性能测定培养基中,培养5天后,总氮浓度由12415 mg·L-1降至55.39mg·L-1,去除率为55.4%；而硝酸盐浓度由120.15mg ·L-1降至2.67mg·L-1去除率达97.78%；亚硝酸盐浓度呈现“先升高,后降低”的趋势,但始终处在较低水平。菌株K-9接种至模拟微污染水体,培养7d后,有机物浓度由30021mg·L-1降至32.0mg·L-1,去除率达89.3%；总氮浓度由1504mg·L-1降至1242mg·L-1;而硝酸盐浓度由5.11mgL-1降低到299mg·L-1,去除率为41.5%；亚硝酸盐浓度始终维持在较低水平。3、不同环境因素对好氧反硝化作用的影响不同碳源、接种量、初始pH、碳氮比(C/N)、转速以及温度等对菌株D-3的生长和反硝化能力均有显著影响。结果表明：菌株D-3反硝化能力最强时的接种量为1%(V/V),最佳初始pH值为7.0,最佳碳源为丁二酸钠,最佳C/N为12,总氮和硝酸盐去除率最大时的转速为120rpm,最佳温度为30。C。4、复合微生物对实际景观水体污染物的去除效果将三株优势菌进行单菌株(Psb2, D-3, K-9)、两菌株(P+K, D+K, D+P)、三菌株(P+D+K)组合,先将D-3、K-9以及不含Psb2的组合投加到采集的实际水样中振荡培养,Psb2静止光照培养,三天后在上述组合中加入Psb2,继续光照静止培养3天后测定污染物含量,结果表明：复合菌株处理后的总氮(TN)浓度低于单菌株处理且显著低于对照浓度,单菌株对实际水体中总磷(TP)和硝酸盐(N03-)的去除无显著影响,但经复合后对TP的去除率显著增加；菌株K-9对亚硝酸盐(N02-)几乎无去除,而组合P+D+K的去除率明显高于其它组合；无论是单菌株还是组合菌株对氨氮(NH4+)的去除效果都较好,而对有机物(COD)的降解都不高,总之,组合后的菌株对水体六种污染物的去除效果显著优于单菌株。5、固定化微生物对实际景观水体污染物的去除效果实验结果表明固定化小球最佳成分配比为：聚乙烯醇(PVA)浓度10%(m/v),海藻酸钠(SA)浓度3%(m/v),CaCl2浓度2%(m/v)。取1mL(1×108cfu.mL-1)湿菌体制备包埋小球,先将好氧微生物小球放入采集的实际水样中进行振荡处理,三天后加入厌氧微生物小球继续光照静止培养三天,测定水体污染物含量。结果表明：无论是单菌株还是复合菌株经固定化后对六种污染物的去除率都显著高于游离菌株,组合P+D+K对TN的去除效果最好,其去除率为60.6%,七种固定化微生物小球对TP的去除效果相差不大,但复合后的小球其去除率比单菌株稍高；菌株Psb2与K-9对N03-的去除率较低,其余小球相差不大,其中组合P+D+K去除率高达60.1%；七种小球能有效降低NO2和NH4+浓度,而对COD的降解较差,但与游离微生物相比,其COD降解率显著增加。
[Abstract]:Landscape water plays a very important role in urban construction, but because of its small area, poor fluidity and lack of self purification ability, it is easier to produce eutrophication and other pollution. At present, the commonly used method of landscape water treatment is biological method, and the method of microbial treatment is a kind of high efficiency and low cost which is rapidly rising in the former country and abroad. It is known that Bacillus subtilis can decompose macromolecule organic matter into simple organic matter under aerobic conditions for aerobic denitrifying bacteria to provide carbon source and nitrogen source for reducing nitrate, while photosynthetic bacteria can remove the remaining ammonia and nitrogen in water under anaerobic conditions, so this study first uses three kinds of high levels. In order to further improve the removal rate of pollutants, the three kinds of bacteria were immobilized in order to further improve the removal rate of the contaminants. Thus, a method which can effectively be used in the treatment of micro polluted landscape water was explored. In order to further improve the purification effect, we inoculate Bacillus subtilis and aerobic denitrifying bacteria under aerobic conditions, and then add photosynthetic bacteria to remove ammonia nitrogen under anaerobic conditions after the degradation of the macromolecular substance in the water body, and then carry out the three different microbes in order to further improve the purification effect. The combination of two strains and three strains to explore the effect of Compound Microorganism on the removal of pollutants in the actual landscape water. At the same time, in order to prolong the action time of microorganism in the process of pollutant removal and maintain high degradation activity, the microorganism was immobilized and immobilized by PVA and SA. The aerobic microorganism pellets were put into the actual landscape water body, and after a period of time, the anaerobic microorganism pellets were cultured in order to study the removal effect of the immobilized microorganism pellets on the pollutants in the actual polluted water. The main conclusions are as follows: 1, the screening of three kinds of highly effective bacteria and the identification of the bacteria from the natural world Separation, screening and molecular biological identification, three highly effective bacteria were identified as Psb2, Pseudomonas sp. (D-3) and Bacillus subtilis (K-9).2, and three highly effective bacteria were used to remove pollutants from simulated water pollutants, Psb2, and the removal rate of ammonia nitrogen in five different landscape water bodies was 35%-95.88 Between%, Psb2 can effectively remove ammonia nitrogen in the landscape water. Strain D-3 inoculated to the denitrification performance culture medium. After 5 days, the total nitrogen concentration decreased from 12415 mg. L-1 to 55.39mg. L-1, the removal rate was 55.4%, while the nitrate concentration from 120.15mg L-1 to 2.67mg L-1 removal rate was 97.78%; the nitrite concentration showed "first". When the strain K-9 was inoculated to the simulated micro polluted water, the concentration of organic matter decreased from 30021mg to L-1 to 32.0mg. L-1, the removal rate was 89.3%, and the concentration of total nitrogen was reduced from 1504mg. L-1 to 1242mg L-1, while the concentration of nitrate decreased from 5.11mgL-1 to 299mg. The removal rate was 41.5%; nitrite was 41.5%. The concentration of acid salt remained at a lower level of.3, and the effects of different environmental factors on aerobic denitrification were different from carbon sources. The inoculation amount, initial pH, carbon and nitrogen ratio (C/N), rotational speed and temperature had significant influence on the growth and denitrification ability of strain D-3. The results showed that the inoculation amount of the strain D-3 denitrification was 1% (V/V), the best initial stage. The initial pH value is 7, the best carbon source is sodium succinate, the best C/N is 12, the speed of the total nitrogen and nitrate removal rate is 120rpm, the optimum temperature is 30.C.4. The removal effect of the compound microorganism on the actual landscape water pollutants will be three strains of bacteria (Psb2, D-3, K-9), two strains (P+K, D+K, D+P), three strains (P+D+K) combination, first will D-3, K-9 and non Psb2 combination were added to the actual water samples collected by oscillating culture, Psb2 still illumination was cultured. After three days, Psb2 was added to the above combination, and the content of pollutants was determined after 3 days of light still culture. The results showed that the concentration of total nitrogen (TN) after treatment of the compound strain was lower than that of single strain and significantly lower than the control concentration. The strain had no significant effect on the removal of total phosphorus (TP) and nitrate (N03-) in the actual water body, but the removal rate of TP was significantly increased after the combination, and the strain K-9 had almost no removal of nitrite (N02-), while the removal rate of combined P+D+K was significantly higher than that of other combinations, and the removal efficiency of ammonia nitrogen (NH4+) was better than that of single strain or combination strain. The degradation of organic matter (COD) was not high. In a word, the effect of the combined strain on the removal of six pollutants was significantly better than that of single strain.5. The experimental results of the removal effect of immobilized microorganisms on the actual landscape water pollutants showed that the optimum composition of the immobilized microspheres was as follows: the concentration of polyvinyl alcohol (PVA) was 10% (m/v), and the concentration of sodium alginate (SA) was strong. Degree 3% (m/v), CaCl2 concentration 2% (m/v). Take 1mL (1 x 108cfu.mL-1) wet bacteria system to prepare the pellet. First, the aerobic microorganism ball is put into the actual water sample to be oscillated. After three days, the anaerobic microorganism ball is added to the light still for three days to determine the content of the water pollutants. The results show that the single strain or the compound bacteria is a single strain. The removal rate of six kinds of pollutants was significantly higher than that of the free strain. The removal efficiency of TN was best by combination P+D+K, and the removal rate was 60.6%. The removal efficiency of seven immobilized microorganism pellets had little difference, but the removal rate of the pellets was slightly higher than that of the single strain, and the removal rate of N03- was lower than that of the strain Psb2 and K-9. Yu Xiaoqiu has little difference, of which the removal rate of combination P+D+K is as high as 60.1%, and seven kinds of pellets can effectively reduce the concentration of NO2 and NH4+, but the degradation of COD is poor, but the degradation rate of COD is significantly increased compared with the free microorganism.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X52;X172

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