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随着我国经济发展以及城市化进程不断加快,城市污水排放量也在不断增长[1-2]。如何高效处理污水,利用污水开发绿色能源正在成为社会关注的热点[1]。截至2021年,全国城市污水年排放量达6 250 762.73×104 m3,干污泥总产量1 422.90×104 t (含水率80%) [3]。污泥属于高产型可利用资源,在能源回收和资源回收等方面有着重要意义[4]。目前,我国处理剩余污泥主要采用土地利用、焚烧、卫生填埋等方式[5]。这些处理方式不仅会产生污染、占用土地,还使得大量有机质与诸如磷等不可再生资源的浪费。与其他处理手段相比,厌氧消化所产生的资源、能源消耗较少;在利用有机质、回收高品质磷的同时,实现病原菌的弱化与污泥减量,是一种行之有效的处理方式[6]。污泥中有机质的主要利用方式为厌氧发酵产沼气,然而,在传统处理条件下厌氧发酵产生的沼气存在甲烷浓度较低,沼气纯化成本偏高等问题,这极大限制了其应用范围。同时,磷是一种应用广泛的工业、农业原料[7-8],正面临枯竭的风险[9]。因此,在污泥减量的同时利用有机质提升沼气中甲烷浓度,开发磷富集调理和高品质磷回收技术极具经济效益与环境效益。
细胞膜、细胞壁等结构限制了微生物对有机物的利用以及磷的释放回收工作[10]。而游离氨不仅在强化污泥厌氧消化水解方面具有巨大潜力[11],同时对细胞膜的破解作用可使磷元素释放到液相中,为后续高品质磷的回收工作提供基础[12]。这与目前所采用的投加酸、碱、利用电渗析法与超声波[13-15]裂解细胞膜、细胞壁相比,有着低能耗、低成本的显著优势,同时也提供了进一步规模化,产业化的可能。但目前关于游离氨调控对污泥中有机物利用和磷的释放与形态分析研究较少。
基于此,本研究针对污泥游离氨调控对有机物利用和磷形态变化的影响,利用厌氧生物膜反应器进行连续实验,考察在此调控下微生物对有机物的利用转化情况及磷形态转化途径,以期优化污泥资源回收及能量利用技术。
污泥厌氧消化在游离氨调控下强化磷与有机物释放的作用效果
Effect of sludge anaerobic digestion on enhanced release of phosphorus and organic matter under the control of free ammonia
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摘要: 基于污泥资源化与能源化的目的,采用游离氨调控的方式,利用系统中有机质提高沼气中甲烷体积分数的同时分析系统中磷浓度和形态的变化情况。结果表明,与空白阶段相比,游离氨调控后系统中溶解性蛋白、多糖质量浓度分别提升16.34%和26.43%;沼气中甲烷平均体积分数由73.61%提升至85.04%。通过三维荧光光谱(3D-EEM)和平行因子法(PARAFAC)分析两个反应阶段厌氧污泥上清液,芳香类蛋白质Ⅰ占比分别从35%、47%下降至29%与40%。这表明经过游离氨调控后芳香类蛋白质Ⅰ利用效果略有提高。在磷形态分析方面,游离氨调控使得进出水总磷、磷酸盐质量浓度分别提升948.64%、1 219.35%、2 254.55%与2 280%,磷释放效果明显。根据X 射线能量色散谱(EDS)、傅里叶红外光谱(FTIR)与X射线光电子能谱(XPS) 分析结果表明,污泥中P主要与Fe、Al等金属元素以复合盐的形式存在;并在厌氧消化过程中发生了一定比例的磷形态转化。但游离氨诱导磷形态转化的机理仍需进一步探究。该研究结果进一步表明游离氨在厌氧消化过程中调控强化了有机物的利用效果,促进磷的释放与形态变化。该研究结果可为基于游离氨调控下有机物与磷的释放提供参考。Abstract: For the purpose of sludge resource utilization and energy utilization, free ammonia was adopted to control the organic matter in the system to increase the volume fraction of methane in biogas while analyzing the changes of phosphorus concentration and form in the system. The experimental results showed that, compared with the blank stage, the mass concentration of soluble protein and polysaccharide in the system increased by 16.34% and 26.43% respectively, and the average volume fraction of methane in biogas increased from 73.61% to 85.04%. Through three-dimensional fluorescence spectroscopy (3D-EEM) and parallel factor method (PARAFAC) analysis of the two reaction stages of anaerobic sludge supernatant, the proportion of aromatic protein I decreased from 35% and 47% to 29% and 40%, respectively, indicating that the utilization of aromatic protein I was slightly improved after free ammonia regulation. In the aspect of phosphorus speciation analysis, the free ammonia regulation increased the total phosphorus and phosphate concentration in the water inlet and outlet by 948.64%, 1219.35%, 2254.55% and 2280% respectively, and the phosphorus release effect was obvious. According to the analysis results of X-ray energy dispersion spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), it was found that P mainly existed in the form of complex salt with Fe, Al and other metal elements in the sludge, and a certain proportion of phosphorus transformation occurred in the process of anaerobic digestion. However, furhter study was still needed to investigate the mechanism of phosphorus transformation induced by free ammonia. The results further showed that the regulation of free ammonia enhanced the utilization of organic matter and promoted the release and morphological change of phosphorus in the process of anaerobic digestion. The results of this study can provide a reference for the release of organic matter and phosphorus under the regulation of free ammonia.
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表 1 不同阶段实验浓缩污泥初始特性
Table 1. Initial characteristics of concentrated sludge at different experiment stages
阶段 TCOD/ (mg·L−1) SCOD/ (mg·L−1) TOC / (mg·L−1) 总固体 / (g·L−1) 挥发性固体/ (mg·L−1) 可溶性蛋白质 / (mg·L−1) 可溶性多糖/ (mg·L−1) pH TIC/ (mg·L−1) [NH+ 4-N] /
(mg·L−1)阶段1 19 970±40.50 56.50±1.50 18.69±0.89 23.29±0.24 14.23±0.15 25.07±1.39 16.06±0.45 7.22±0.10 139.05±30.35 368.50±96.50 阶段2 19 315±165 70.5±1.25 22.59±3.01 21.55±0.97 13.17±0.12 27.88±1.24 14.13±0.83 7.93±0.21 121±13.15 1 531.61±297.37 -
[1] 安叶, 张义斌, 黎攀, 等. 我国市政生活污泥处置现状及经验总结[J]. 给水排水, 2021, 57(S1): 94-98. [2] 刘鑫, 惠秀娟, 唐凤德. 我国典型城市污泥产生量处理处置现状及经济学趋势分析[J]. 环境保护与循环经济, 2021, 41(4): 88-93. [3] 中华人民共和国住房和城乡建设部. 2021 年城建设统计年鉴 [J]. 北京: 中国统计出版社, 2022. [4] 戴晓虎. 我国污泥处理处置现状及发展趋势[J]. 科学, 2020, 72(6): 30-34. [5] 戴晓虎, 张辰, 章林伟, 等. 碳中和背景下污泥处理处置与资源化发展方向思考[J]. 给水排水, 2021, 57(3): 1-5. [6] 胡德秀, 张艳, 朱玲, 等. 污泥厌氧过程中磷释放与 SMP 特性研究[J]. 中国环境科学, 2018, 38(8): 2974-2980. [7] ZHU F, CAKMAK E K, CETECIOGLU Z. Phosphorus recovery for circular Economy: Application potential of feasible resources and engineering processes in Europe[J]. Chemical Engineering Journal, 2023, 454: 140153. doi: 10.1016/j.cej.2022.140153 [8] CHRISPIM M C, SCHOLZ M, NOLASCO M A. Phosphorus recovery from municipal wastewater treatment: Critical review of challenges and opportunities for developing countries[J]. Journal of environmental management, 2019, 248: 109268. doi: 10.1016/j.jenvman.2019.109268 [9] SAKTAYWIN W, TSUNO H, NAGARE H, et al. Advanced sewage treatment process with excess sludge reduction and phosphorus recovery[J]. Water research, 2005, 39(5): 902-910. doi: 10.1016/j.watres.2004.11.035 [10] 刘博文. 游离氨预处理对污泥厌氧消化的影响机理研究 [D]. 长沙: 湖南大学, 2018. [11] 沈嘉辉, 王侃宏, 郁达伟, 等. 游离氨调理污泥厌氧消化过程研究进展[J]. 现代化工, 2022, 42(S2): 22-28. [12] XU Q, LIU X, WANG D, et al. Free ammonia-based pretreatment enhances phosphorus release and recovery from waste activated sludge[J]. Chemosphere, 2018, 213: 276-284. doi: 10.1016/j.chemosphere.2018.09.048 [13] TAN Z, LAGERKVIST A. Phosphorus recovery from the biomass ash: A review[J]. Renewable and Sustainable Energy Reviews, 2011, 15(8): 3588-3602. doi: 10.1016/j.rser.2011.05.016 [14] GUEDES P, COUTO N, OTTOSEN L M, et al. Phosphorus recovery from sewage sludge ash through an electrodialytic process[J]. Waste Management, 2014, 34(5): 886-892. doi: 10.1016/j.wasman.2014.02.021 [15] XU D C, ZHONG C Q, YIN K H, et al. Alkaline solubilization of excess mixed sludge and the recovery of released phosphorus as magnesium ammonium phosphate[J]. Bioresource Technology, 2018, 249: 783-790. doi: 10.1016/j.biortech.2017.10.065 [16] 沈嘉辉, 王侃宏, 郁达伟, 等. 游离氨调理污泥厌氧消化优化产甲烷过程与强化有机物释放[J]. 化工学报, 2022, 73(9): 4147-4155. [17] MENG X, YU D, WEI Y, et al. Endogenous ternary pH buffer system with ammonia-carbonates-VFAs in high solid anaerobic digestion of swine manure: An alternative for alleviating ammonia inhibition?[J]. Process Biochemistry, 2018, 69: 144-152. doi: 10.1016/j.procbio.2018.03.015 [18] WANG Y, WANG J, PANG J, et al. Introduction of protonic potential of Brønsted− Lowry acids and bases to the quantification of the energy of proton translocation and elucidation of oxidative phosphorylation[J]. Journal of Electroanalytical Chemistry, 2020, 860: 113909. doi: 10.1016/j.jelechem.2020.113909 [19] SCHLESNER S K, VOSS M, HELFER G A, et al. Smartphone-based miniaturized, green and rapid methods for the colorimetric determination of sugar in soft drinks[J]. Green Analytical Chemistry, 2022, 1: 100003. doi: 10.1016/j.greeac.2022.100003 [20] FANG H H P, ZHANG T. Anaerobic biotechnology: environmental protection and resource recovery [M]. World Scientific, 2015. [21] 冷欢, 杨清, 黄钢锋, 等. 氢营养型产甲烷代谢途径研究进展[J]. 微生物学报, 2020, 60(10): 2136-2160. doi: 10.13343/j.cnki.wsxb.20190583 [22] COSTA J, BARBOSA S, ALVES M, et al. Thermochemical pre-and biological co-treatments to improve hydrolysis and methane production from poultry litter[J]. Bioresource technology, 2012, 111: 141-147. doi: 10.1016/j.biortech.2012.02.047 [23] MAJD S S A M A, KARBASSI A, ET AL. Effect of physical and chemical operating parameters on anaerobic digestion of manure and biogas production: A review [J]. Journal of Environmental Health and Sustainable Development, 2017. [24] LI L, WANG Y, ZHANG W, et al. New advances in fluorescence excitation-emission matrix spectroscopy for the characterization of dissolved organic matter in drinking water treatment: a review[J]. Chemical Engineering Journal, 2020, 381: 122676. doi: 10.1016/j.cej.2019.122676 [25] WANG D, LIU Y, NGO H H, et al. Approach of describing dynamic production of volatile fatty acids from sludge alkaline fermentation[J]. Bioresource Technology, 2017, 238: 343-351. doi: 10.1016/j.biortech.2017.04.054 [26] XU Q, LIU X, FU Y, et al. Feasibility of enhancing short-chain fatty acids production from waste activated sludge after free ammonia pretreatment: role and significance of rhamnolipid[J]. Bioresource technology, 2018, 267: 141-148. doi: 10.1016/j.biortech.2018.07.018 [27] ONG H C, CHEN W H, SINGH Y, et al. A state-of-the-art review on thermochemical conversion of biomass for biofuel production: A TG-FTIR approach[J]. Energy Conversion and Management, 2020, 209: 112634. doi: 10.1016/j.enconman.2020.112634 [28] 许光眉, 施周, 邓军. 石英砂负载氧化铁吸附除锑, 磷的 XRD, FTIR 以及 XPS 研究[J]. 环境科学学报, 2007, 27(3): 402-407. [29] 唐明珠, 王志英, 王云山, 等. EBSD-XPS 法分析磷石膏中杂质物相[J]. 光谱学与光谱分析, 2022, 42(1): 136-140.