共查询到20条相似文献,搜索用时 62 毫秒
1.
Yi Chen Shilong He Mengmeng Zhou Tingting Pan Yujia Xu Yingxin Gao Hengkang Wang 《Frontiers of Environmental Science & Engineering》2018,12(5):13
2.
Yishan Lin Yanling He Zhuo Meng Shucheng Yang 《Frontiers of Environmental Science & Engineering》2008,2(2):241-246
The direct conversion of methanol into methane is the main process in anaerobic treatment of methanol containing wastewater. However, acetic acid can also be produced from methanol theoretically, which may probably result in an abrupt pH drop and deteriorate the anaerobic process. Therefore, it is interesting to know what would really happen in an anaerobic reactor treating methanol wastewater. In this study, an up-flow anaerobic sludge bed (UASB) reactor treating methanol wastewater was operated. The chemical oxygen demand (COD), acetic acid and pH of the effluent were monitored at different loadings and influent alkalinity. The results showed that the anaerobic reactor could be operated steadily at as low as 119 mg/L of influent alkalinity and high organic loading rate with no obvious pH drops. Volatile fatty acids accumulation was not observed even at strong shock loadings. The microorganisms in the sludge at the end of the test became homogeneous in morphology, which were mainly spherical or spheroidal in shape. 相似文献
3.
Ruijie Li Mengmeng Zhou Shilong He Tingting Pan Jing Liu Jiabao Zhu 《Frontiers of Environmental Science & Engineering》2021,15(5):91
4.
Wang Zhenyao Li Xuan Siddiqui Muhammad Ahmar Liu Huan Zhou Ting Zheng Lei Huang Siyu Gao Li Lin Carol Sze Ki Wang Qilin 《Environmental Chemistry Letters》2023,21(5):3023-3040
Environmental Chemistry Letters - Anaerobic digestion is a promising technology for energy recovery from secondary sludge, yet the presence of humic substances in wastewater limits anaerobic... 相似文献
5.
Chong-Jian Tang Cheng-Shan Duan Cheng Yu Yu-Xia Song Li-Yuan Chai Ruiyang Xiao Zongsu Wei Xiao-Bo Min 《Environmental Chemistry Letters》2017,15(2):311-328
Nitrogen pollution of waters has sometimes caused severe eutrophication, leading to the death of fishes and most aquatic life. There is therefore a need for efficient and cost-effective methods to remove nitrogen from ammonium-rich wastewaters. Anaerobic ammonium oxidation (ANAMMOX) is a promising process to remove nitrogen because this process directly oxidizes ammonium (NH4 +) to dinitrogen gas (N2) under anoxic condition. Nonetheless, a challenge of this process is that chemolithoautotrophic Anammox bacteria grow slowly at the beginning, thus resulting in low Anammox biomass and instability of reactors. Such issues can be overcome by granulation of the Anammox sludge. Here, we review the characteristics of the Anammox bacteria, and the formation, structure and flotation of Anammox granules under high hydraulic loadings. We also evaluate the performances of full-scale granular Anammox processes. The major points are: 1) Anammox bacteria secrete a large amount of extracellular polymeric substances (EPS), up to 415 mg g?1 of volatile suspended solids (VSS), containing many hydrophobic functional groups that facilitate biomass granulation. 2) Granulation enhances the sludge settling property and retention time, which contributes to the extremely high nitrogen removal rate of 77 kg m?3 d?1 of Anammox upflow reactors. 3) Flotation of Anammox granules frequently occurs under nitrogen removal rate higher than 10 kg m?3 d?1, which is mainly due to the overproduction of EPS under high hydraulic conditions. 相似文献
6.
Guochen ZHENG Jianzheng LI Feng ZHAO Liguo ZHANG Li WEI Qiaoying BAN Yongsheng ZHAO 《Frontiers of Environmental Science & Engineering》2012,6(1):125-130
To investigate the influence of illumination on the fermentative hydrogen production system, the hydrogen production efficiencies of two kinds of anaerobic activated sludge (floc and granule) from an anaerobic baffled reactor were detected under visible light, dark and light-dark, respectively. The 10 mL floc sludge or granular sludge was respectively inoculated to 100 mL diluted molasses (chemical oxygen demand of 8000 mg·L-1) in a 250 mL serum bottle, and cultured for 24 h at 37°C under different illumination conditions. The results showed that the floc was more sensitive to illumination than the granule. A hydrogen yield of 19.8 mL was obtained in the dark with a specific hydrogen production rate of 3.52 mol·kg-1MLVSS·d-1 (floc), which was the highest among the three illumination conditions. Under dark condition, the hydrogen yield of floc sludge reached the highest with the specific hydrogen production rate of 3.52 mol·kg-1MLVSS·d-1, and under light-dark, light, the specific hydrogen production rate was 3.11 and 2.21 mol·kg-1MLVSS·d-1, respectively. The results demonstrated that the illumination may affect the dehydrogenase activity of sludge as well as the activity of hydrogen-producing acetogens and then impact hydrogen production capacity. 相似文献
7.
城市污水处理厂进行脱氮除磷工艺时,大量的磷从水体转入活性污泥中,如不能回收这部分磷,将造成磷的大量流失,这与磷矿稀缺的现状形成矛盾。通过建立污泥停留时间5 d和10 d的两个厌氧反应系统,对污泥中磷的释放规律进行研究,并采用鸟粪石法对上清液中的磷进行回收。研究结果表明,厌氧污泥上清液中的磷含量高达150 mg.L-1,SRT为5 d和10 d的系统,分别在4 d和2 d后磷的质量浓度由14 mg.L-1上升到100 mg.L-1,且基本上都以正磷酸盐的形式存在。将pH从8.3上升到9.0,磷的回收率可以从60%提升到90%,当pH达到8.8时,磷的回收率即可超过80%,表现出了较好的磷回收效果。研究还发现镁离子和磷酸根的摩尔比对磷的回收率的影响较小,在pH=8.8时,将镁磷比从1.43提升到1.83,磷的回收率仅从79.2%提升到85.5%;在pH=9.0时提高镁磷比对磷的回收基本没有影响。 相似文献
8.
G. Pavlogeorgatos 《毒物与环境化学》2013,95(4-6):159-167
The primal purpose of this research project is to examine the size distribution of the Suspended Solids (SS) of an activated sludge pilot plant, under different operational conditions and during the introduction of wastewater contaminated with mercury of different concentrations (10–100 µg/L Hg(NO3)2). While the experiment was being conducted, the most important parameters of the pilot plant (COD, TOC, MLSS, SS, NH4, PO4, total number of bacteria – coccoids and rods, pH, DO, T etc.) were measured; this fact led to the inference of conclusions that connect the distribution of the size of the SS with those parameters. The main conclusions of this research work are: (a) the important interaction of the removal ability of the organic loading of the plant and the size distribution of the SS at the aeration tank and the outlet of the plant and (b) the input of the mercury-contaminated wastewater at the plant affects the size distribution of the SS at the aeration tank. The second conclusion probably indicates a possible way that microorganisms of the aeration tank react to the introduction of mercury. 相似文献
9.
10.
添加剂对污泥厌氧消化性能的影响 总被引:1,自引:0,他引:1
在间歇培养条件下,研究了还原型辅酶Ⅱ(NADPH)、乙酰辅酶A(Acetyl Co A)和对氨基苯甲酸(PABA)3种添加剂对污泥厌氧消化性能的影响.结果表明,3种微生物活性促进剂均能促进污泥厌氧消化产气.其中,NADPH的促进效果最为显著,消化第35 d,产甲烷量比对照组高15.90%.在污泥含固率为3%、未调初始pH(pH=6.7)和温度35℃的厌氧消化条件下,NADPH的最佳添加量为50 mg.L-1,消化第36 d,污泥累积产甲烷量127.13 mL.g-1VSS.在含固率3%、初始pH=8.5、温度55℃和NADPH添加量为50 mg.L-1的工艺条件下,污泥厌氧产气效果最佳,消化第30 d时累积产甲烷量达158.02 mL.g-1VSS. 相似文献
11.
Mingxia ZHENG Zhong YAN Jiane ZUO Kaijun WANG 《Frontiers of Environmental Science & Engineering》2014,8(5):797-804
Bed expansion serves an important function in the design and operation of an upflow anaerobic reactor. An analysis of the flow pattern of expanded granular sludge bed (EGSB) reactors shows that most EGSB reactors do not behave as expanded bed reactors, as is widely perceived. Rather, these reactors behave as fluidized bed reactors based on the classic chemical reactor theory. In this paper, four bed expansion modes, divided as static bed, expanded bed, suspended bed, and fluidized bed, for bioreactors are proposed. A high-rate anaerobic suspended granular sludge bed (SGSB) reactor was then developed. The SGSB reactor is an upflow anaerobic reactor, and its expansion degree can be easily controlled within a range to maintain the suspended status of the sludge bed by controlling upfiow velocity. The results of the full-scale reactor confirmed that the use of SGSB reactors is advantageous. The full-scale SGSB reactor runs stably and achieves high COD removal efficiency (about 90%) at high loading rates (average 40 kg-COD·m^-3·d^-1, maximum to 52 kg·COD·m^-3 ·d^-1) based on the SGSB theory, and its expansion degree is between 22% and 37%. 相似文献
12.
The inhibitory efficiency of anionic copolymers and the effect of the biocides sodium hypochlorite, glutaraldehyde, and tris(hydroxymethyl)nitromethane on the precipitation behavior of calcium fluoride (CaF2) were studied. The efficiency of polymeric inhibitors was traced from conductivity measurements by using half-life (t1/2) method. X-ray diffraction parameters have been measured for calcium fluoride scale minerals. An anionic copolymer (K-798) acts as one of the best inhibitors for the precipitation process of the calcium fluoride in water as compared to K-775. It is assigned to the fact that the copolymer (K-798) contains both sulfonic acid and sulfonated styrene groups while the polymer (K-775) having only the sulfonic acid group. It was further observed that the biocides have no appreciable effect on the performance of the anionic polymeric inhibitors. 相似文献
13.
研究了杂环类(吡啶、喹啉)和酚类(间甲酚、二甲酚、苯酚)有机物对磷酸铵镁结晶法(MAP,magnesium ammonium phosphate)处理废水中氨氮的影响.研究表明,杂环和酚类有机物均对MAP法的除氮效果产生抑制作用,杂环类有机物的抑制作用大于酚类有机物,其中加入吡啶、喹啉、间甲酚、二甲酚、苯酚相比于对照组(21 mg·L-1),氨氮残余浓度分别升高45.17、56.66、43.01、50.68、49.72 mg·L-1.因为络合作用和吸附作用,多组分体系MAP晶体产生的抑制作用强于单一组分体系. 相似文献
14.
Tingting Zhu Zhongxian Su Wenxia Lai Jiazeng Ding Yufen Wang Yingxin Zhao Yiwen Liu 《Frontiers of Environmental Science & Engineering》2023,17(1):7
15.
Jun Li Wentao Li Gan Luo Yan Li Aimin Li 《Frontiers of Environmental Science & Engineering》2019,13(1):6
16.
Sijia Ai Hongyu Liu Mengjie Wu Guangming Zeng Chunping Yang 《Frontiers of Environmental Science & Engineering》2018,12(6):3
Three acid-producing strains, AFB-1, AFB-2 and AFB-3, were isolated during this study, and their roles in anaerobic digestion of waste activated sludge (WAS) were evaluated. Data of 16S rRNA method showed that AFB-1 and AFB-2 were Bacillus coagulans, and AFB-3 was Escherichia coli. The removal in terms of volatile solids (VS) and total chemical oxygen demand (TCOD) was maximized at 42.7% and 44.7% by inoculating Bacillus coagulans AFB-1. Besides, the optimal inoculum concentration of Bacillus coagulans AFB-1 was 30% (v/v). Solubilization degree experiments indicated that solubilization ratios (SR) of WAS reached 20.8%±2.2%, 17.7%±1.48%, and 11.1%±1.53%. Volatile fatty acids (VFAs) concentrations and compositions were also explored with a gas chromatograph. The results showed that VFAs improved by 98.5%, 53.0% and 11.6% than those of the control, respectively. Biochemical methane potential (BMP) experiments revealed that biogas production increased by 90.7% and 75.3% when inoculating with Bacillus coagulans AFB-1 and AFB-2. These results confirmed that the isolated acid-producing bacteria, especially Bacillus coagulans, was a good candidate for anaerobic digestion of WAS.
相似文献
17.
Lihui Gao Yijun Cao Lizhang Wang Shulei Li 《Frontiers of Environmental Science & Engineering》2022,16(6):77
18.
Yuyao ZHANG Huan LI Can LIU Yingchao CHENG 《Frontiers of Environmental Science & Engineering》2015,9(6):1108-1116
High-solids anaerobic digestion of sewage sludge was a promising process, but high solid concentration negatively influenced methane production. The influencing mechanism was systematically analyzed in this study through a series of static anaerobic digestion experiments at total solids (TS) contents of 3%–15%. The results showed that TS 6% was the boundary between low-solids and high-solids anaerobic digestion, and the accumulative methane yield decreased exponentially when TS increased from 6% to 15%. The performance of anaerobic digestion was directly determined by the efficiency of mass transfer, and the relation between methane yield and sludge diffusive coefficients was well described by a power function. Thus, the increasing TS resulted in an exponential increase in sludge viscosity but an exponential decrease in diffusive coefficient. The blocked mass transfer led to the accumulation of volatile fatty acids (VFAs) and free ammonia. Acetic metabolism was the main process, whereas butyric and propionic metabolisms occurred at the initial stage of high-solids anaerobic digestion. The concentration of VFAs reached the maximum at the initial stage, which were still lower than the threshold influencing methanogens. The concentration of free ammonia increased gradually, and the methanogenesis was inhibited when free ammonia nitrogen exceeded 50 mg·L−1. Consequently, the deterioration of high-solids anaerobic digestion was related to the blocked mass transfer and the resulting ammonia accumulation. 相似文献
19.
For biological nitrogen (N) removal from wastewater, a sufficient organic carbon source is requested for denitrification. However, the organic carbon/nitrogen ratio in municipal wastewater is becoming lower in recent years, which increases the demand for the addition of external organic carbon, e.g. methanol, in wastewater treatment. The volatile fatty acids (VFAs) produced by acidogenic fermentation of sewage sludge can be an attractive alternative for methanol. Chemically enhanced primary sedimentation (CEPS) is an effective process that applies chemical coagulants to enhance the removal of organic pollutants and phosphorus from wastewater by sedimentation. In terms of the chemical and biological characteristics, the CEPS sludge is considerably different from the conventional primary and secondary sludge. In the present study, FeCl3 and PACl (polyaluminum chloride) were used as the coagulants for CEPS treatment of raw sewage. The derived CEPS sludge (Fe-sludge and Al-sludge) was then processed with mesophilic acidogenic fermentation to hydrolyse the solid organics and produce VFAs for organic carbon recovery, and the sludge acidogenesis efficiency was compared with that of the conventional primary sludge and secondary sludge. The results showed that the Fe-sludge exhibited the highest hydrolysis and acidogenesis efficiency, while the Al-sludge and secondary sludge had lower hydrolysis efficiency than that of primary sludge. Utilizing the Fe-sludge fermentation liquid as the carbon source for denitrification, more than 99% of nitrate removal was achieved in the main-stream wastewater treatment without any external carbon addition, instead of 35% obtained from the conventional process of primary sedimentation followed by the oxic/anoxic (O/A) treatment.
相似文献