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1.
为高效处理玉米淀粉生产废水,启动并持续运行了一个四格室厌氧折流板反应器(ABR),通过分阶段提升进水COD的方法,探讨了有机负荷率(OLR)对ABR运行效能的影响,并采用间歇培养方式考察了OLR对沿程格室中不同营养类型产甲烷菌群活性的影响.结果表明,在OLR分阶段从2.7提高到8.0 kg·m-3·d-1的过程中,ABR前两个格室(C1和C2)始终呈现出典型的产酸发酵特征,其污泥的有机挥发酸(VFAs)比产率为0.54~0.76 kg·kg-1·d-1(以每天每千克MLVSS产出的1千克有机挥发酸计,下同),而后两个格室(C3和C4)则表现出典型的产甲烷特征,其污泥的比产甲烷速率达98 L·kg-1·d-1(以每天每千克MLVSS产出的1升甲烷计,下同)以上.活性污泥产甲烷活性测试结果表明,当OLR为2.7~8.0 kg·m-3·d-1时,C3中的氢营养型产甲烷菌群保持了较高的产甲烷活性,其最大甲烷产量(Pmax)和最大比产甲烷速率分别达到了20.4 mL和16.5 mL·g-1·h-1(以每小时每克MLVSS产出的1毫升甲烷计,下同)以上.乙酸营养型产甲烷菌群的累计甲烷产量由大到小依次为:C3 > C4 > C1 > C2.经过144 h的培养后,C3中乙酸营养型产甲烷菌群的累计甲烷产量为15.1~15.2 mL,最大比产甲烷速率为10.0~10.8 mL·g-1·h-1.  相似文献   

2.
为提高餐厨垃圾沼气工程能源利用效率.本试验采用全混合式连续发酵,通过调控餐厨垃圾高温厌氧发酵过程中OLR变化,探究OLR为0.7、1.2、4.4 kg·m-3·d-1下产气性能、pH、SCOD和VFAs等参数变化.结果表明,反应器能在0.7 kg·m-3·d-1下低负荷启动,此阶段产气性能较差,VFAs浓度受正丁酸含量增长缓慢上升,但仍处于低浓度范围.OLR提升至1.2 kg·m-3·d-1,正丁酸分解成乙酸速率加快,乙酸浓度比0.7 kg·m-3·d-1阶段增长17.36%,发酵液中VFAs积累导致系统酸化抑制产甲烷菌产气性能,外加碱溶液无法调控酸碱平衡.OLR为4.4 kg·m-3·d-1时,VFAs浓度增长趋于平稳,调节pH至6.7以上反应器稳定运行.随着产甲烷菌活性恢复,沼气产量维持在25 L·d-1左右,VFAs浓度快速下降并稳定在19.68~21.30 g·L-1之间.实际沼气工程可控制OLR在0.7 kg·m-3·d-1下启动,待发酵系统稳定运行后增加OLR至4.4 kg·m-3·d-1同时调节pH到6.7以上,可以达到最佳产沼气工艺.而维持OLR在1.2 kg·m-3·d-1更适合获得高浓度VFAs.  相似文献   

3.
投加Fe3O4能够在一定程度上强化有机物的厌氧降解过程,而进水有机负荷是影响厌氧系统处理效率的重要因素.本研究通过分阶段提升进水有机负荷,对比考察了Fe3O4的加入对UASB厌氧反应器运行效能及污泥性质的影响.结果表明,当有机负荷低于3.2 kg·m-3·d-1时,两反应器内有机物厌氧水解效率并无显著性差别.而当有机负荷提升至6.4、12.8、25.6 kg·m-3·d-1时,Fe3O4对有机物厌氧水解效率表现出一定的促进效果,且有机负荷越高,Fe3O4对厌氧水解的促进效果越显著.与此同时,Fe3O4对厌氧产甲烷过程也表现出明显的促进作用,在有机负荷分别为1.6、3.2、6.4、12.8、25.6 kg·m-3·d-1时,添加Fe3O4的反应器中平均甲烷产率分别为对照组的3.55、2.37、1.26、1.16和1.06倍.这一现象表明Fe3O4对产甲烷过程的促进效果与有机负荷密切相关,且有机负荷越低,Fe3O4对厌氧产甲烷效率的增强作用越明显.此外,本研究还分析了运行过程中污泥粒径和胞外聚合物的变化,发现Fe3O4的加入可以有效促进厌氧污泥颗粒化进程.  相似文献   

4.
有机负荷和温度波动对厌氧菌群及酶活影响   总被引:1,自引:0,他引:1  
于钦  冯磊  甄箫斐 《环境科学学报》2020,40(12):4358-4367
基于太阳能辅热厌氧消化反应器进行餐厨垃圾半连续发酵试验,探究了温度波动和有机负荷调控(OLR=2.0、4.0、6.0、7.0 kg·m-3·d-1)对甲烷产量、酶活性变化和微生物群落结构的影响.结果表明,反应器可以在OLR为2.0 kg·m-3·d-1下稳定运行并在6.0 kg·m-3·d-1时实现最佳甲烷生产效率,虽然太阳能组比电能组减少了4倍能耗,但热辐射不稳定导致太阳能组发酵温度波动,甲烷平均产量比电能组减少21%.此外,蛋白酶在温度波动环境下表现出较高活性,但脂肪酶和淀粉酶活性却受到抑制.高通测序结果表明,低OLR阶段乙酸型产甲烷菌Methanosaeta活性较强,随着OLR递增氢营养型产甲烷菌MethanoregulaMethanospirillum相对丰度逐渐提高,而试验全过程中水解细菌Firmicutes相对丰度维持在62%~95%,占据主导地位.  相似文献   

5.
移动床生物膜反应器净化模拟水产养殖废水的研究   总被引:1,自引:0,他引:1  
采用移动床生物膜反应器(MBBR)净化模拟水产养殖废水.结果表明,MBBR净化模拟水产养殖废水效果良好.在水力停留时间(HRT)为8 h,DO为2.0~3.0 mg·L-1的条件下,反应器启动迅速、运行稳定,能使COD和氨氮去除率均达到80%以上,TP去除率达到50%左右;有机负荷为(0.76±0.03)kg·m-3·d-1时,TN及氨氮去除效果最好,去除率分别达到71.73%及98.42%.为达到良好的TN去除效果,有机负荷不宜低于0.5 kg·m-3·d-1;DO为(3.00±0.25)mg·L-1时,TN去除效果最好,最有利于同步硝化反硝化;为保持较高的氨氮去除效率,并减少亚硝态氮积累,DO浓度不应低于2.0 mg·L-1;HRT过短会使氨氮去除效率降低,且可能出现亚硝态氮积累;采用序批式进水运行方式,对TP的去除效果优于连续进水方式,但运行周期后半段会出现亚硝态氮积累,对鱼类产生危害.  相似文献   

6.
我国厨余垃圾产量巨大,含固率在25%左右,不适于填埋,厨余垃圾处理亟待寻找其他出路.本研究在中温((37±1)℃)条件下,构建了垂直流厌氧处理系统处理高含固厨余垃圾,并对其启动阶段运行效能及启动后系统微生物群落结构进行了分析.稳定运行后,系统容积负荷为9.79 g·L-1·d-1,挥发性固体(VS)降解率为80.57%±4.10%,比产气率(SBP)和比甲烷产率(SMP)分别为(0.748±0.078)L·g-1·d-1和(0.405±0.052)L·g-1·d-1,系统缓冲能力强,具有良好的产气能力,不存在酸抑制和氨抑制的情况.对不同位置的微生物群落结构进行分析,细菌在反应器主体的优势菌为Chloroflexi菌门中的Levilinea菌属,参与碳水化合物水解酸化的细菌分布较广;古菌的优势菌属则为MethanothrixMethanobacteriumMethanolinea,均与产甲烷有关.  相似文献   

7.
一段式亚硝化厌氧氨氧化SMBBR处理中低浓度氨氮废水   总被引:2,自引:1,他引:1  
在常温条件下,采用一段式亚硝化厌氧氨氧化SMBBR处理中低氨氮浓度废水.结果表明,在进水氨氮浓度为100 mg·L-1,溶解氧为0.4~0.7 mg·L-1条件下,负荷(以N计)为0.16 kg·(m3·d)-1,去除率可达(51.58±6.80)%,实现了一段式亚硝化厌氧氨氧化的稳定运行.AOB、ANAMMOX和NOB活性分别稳定在(2253.21±502.10)、(4847.46±332.89)和(1455.17±473.83)mg·(m2·d)-1,AOB和ANAMMOX菌之间形成了良好的协同作用.高通量结果显示,Ca.Brocadia(ANAMMOX)、Nitrosomonas(AOB)和Nitrospira(NOB)占比分别为11.57%、1.01%和0.94%.一段式部分亚硝化厌氧氨氧化工艺的稳定运行为厌氧氨氧化技术处理中低浓度氨氮废水提供了参考.  相似文献   

8.
哈尔滨市秸秆焚烧大气污染负荷估算方法研究   总被引:2,自引:1,他引:1  
本文针对近些年哈尔滨秋末冬初大气污染程度增加的溯源问题,基于静风污染气象及降雪对秸秆焚烧的影响等基本假设,采用箱式模型和优化拟合的方法对秸秆焚烧产生污染物的源强及其负荷进行了估算.通过对2015年和2017年典型时段数据的优化拟合得到降雪前重污染天气下PM10排放源强分别为20.16、21.83 μg·m-2·s-1,CO的排放源强分别为149.32、138.65 mg·m-2·s-1;降雪后重污染天气下PM10排放源强分别为15.98、7.09 μg·m-2·s-1,CO的排放源强分别为122.91、89.21 mg·m-2·s-1.由降雪前后各污染物的源强差得到2015年和2017年秸秆焚烧产生的PM10的排放源强分别为4.18、14.74 μg·m-2·s-1,负荷分别为20.73%、67.52%;CO的排放源强分别为26.41、49.44 mg·m-2·s-1,负荷分别为17.69%、35.66%.本文为相关清单的研究提供了一种客观的校核方法,具有重要的社会、环境及现实意义.  相似文献   

9.
李金成  郭雅妮  齐嵘  杨敏 《环境科学》2021,42(8):3866-3874
对相同进水、平行运行的A2/O与倒置A2/O工艺的冬季氨氮(NH4+-N)去除能力进行了全面解析.在运行水温为14℃时,倒置A2/O工艺表现出更低的NH4+-N容积去除负荷[0.13 kg·(m3·d)-1和0.29 kg·(m3·d)-1]和氨氧化速率(AOR)[0.07 kg·(kg·d)-1和0.11 kg·(kg·d)-1],而26℃时两个工艺则相差无几.两个平行工艺中的氨氧化菌(AOB)种群定量结果几乎始终相等(倒置A2/O工艺为3.2%±0.24%,A2/O工艺为3.4%±0.31%).克隆文库分析的结果表明,造成低温时倒置A2/O工艺中具有较低氨氮去除能力的原因是其AOB优势种属为AOR较慢的慢生型(K-生长策略)亚硝化螺菌属(Nitrosospira),而在A2/O工艺中则为AOR较快的快生型(r-生长策略)亚硝化单胞菌属(Nitrosomonas);而在26℃环境下两个工艺中的优势种属则均为Nitrosomonas.结合对污染物沿程去除过程的全面分析,发现尽管温度是决定AOB优势种属演替的首要原因,但由于倒置A2/O的工艺结构变化造成其好氧单元具有较高的COD负荷和高NH4+-N浓度等不利于AOB生长的因素,决定了其可以在常规城市污水的条件下出现K-生长策略型的优势AOB种属.因此倒置A2/O针对异养菌(聚磷菌与反硝化菌)的工艺构造变化却通过COD负荷等间接影响到自养型氨氧化菌的种群分布与演替,并最终造成工艺在低温条件下硝化能力的减弱.  相似文献   

10.
采用中空纤维膜接触器(Hollow Fiber Membrane Contactor, HFMC)回收尿液中的氨氮,系统研究了吸收液类型(H3PO4、H2SO4和HNO3)对氨回收效能、水蒸气的跨膜通量和所获液体肥料的影响.结果表明,使用H2SO4作为吸收液时氨氮回收效能最优,其次是H3PO4和HNO3.当采用H2SO4为吸收液时,氨氮回收率、氨跨膜通量和传质系数分别为84.49%±0.01%、22.92 g·m-2·h-1和2.37×10-6 m·s-1.HNO3的挥发性使其从吸收液侧反向跨膜至料液侧,导致氨跨膜传质驱动力变小;此外,NH3和HNO3会在膜孔中反应并生成NH4NO3气溶胶,增加氨在膜孔中的传质阻力,导致氨氮的回收效能降低.对采用不同吸收液时膜两侧的水的活度差和理论水通量进行了计算,结果表明,随着氨氮的不断跨膜吸收,膜两侧的活度差和水通量逐渐增大,实验结束时水通量分别为7.44×10-2 kg·m-2·h-1(H3PO4)、9.06×10-2 kg·m-2·h-1(H2SO4)和2.00×10-2 kg·m-2·h-1(HNO3).肥料组分分析表明,以H2SO4和HNO3为吸收液可以获得仅含N素的单一液体肥料,以H3PO4作吸收液可获得N-P复合肥,(NH42HPO4和NH4H2PO4所占的比例分别为88.33%和11.67%.  相似文献   

11.
The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.  相似文献   

12.
A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p < 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.  相似文献   

13.
Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis (DGGE) and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity (both in gene richness and diversity index values) and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor (50 mg/kg) recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos (150 mg/kg) caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos (250 mg/kg) produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes (bands) responded differently to the impact of agrochemicals: four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.  相似文献   

14.
Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.  相似文献   

15.
Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury (HgT), combinative mercury (Hgc) and gaseous mercury (HgG), and content of total organic carbon (TOC), but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of (HgG,/HgT)1992〉(HgG/HgT)1996〉〉(HgG/HgT)2000. A simple outline of Hg release in landfill could be drawn: with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants (e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum) are capable of enriching more Hg than herbaceous plants.  相似文献   

16.
The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.  相似文献   

17.
The influence of the nonionic surfactant Tween 80 on pentachlorophenol (PCP) oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration (CMC). Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.  相似文献   

18.
Decomposition of alachlor by ozonation and its mechanism   总被引:1,自引:0,他引:1  
Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.  相似文献   

19.
Several main metabolites of benzo[a]pyrene (BaP) formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone (BP 1,6- quinone), trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (BP 7,8-diol), 3-hydroxybenzo[a]pyrene (3-OHBP), were identified by high-performance liquid chromatography (HPLC). The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that (1) the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; (2) the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; (3) the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% (w/v), concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.  相似文献   

20.
Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.  相似文献   

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