Integrated dark-photo fermentative hydrogen production from synthetic gelatinaceous wastewater via cost-effective hybrid reactor at ambient temperature
Integrated dark-photo fermentative hydrogen production from synthetic gelatinaceous wastewater via cost-effective hybrid reactor at ambient temperature
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DOI：
10.1016/j.enconman.2019.112250
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发表时间：
2020
影响因子：
10.4
通讯作者：
Naira Meky;Mona G. Ibrahim;M. Fujii;Ahmed Elreedy;A. Tawfik
中科院分区：
文献类型：
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作者：
Naira Meky;Mona G. Ibrahim;M. Fujii;Ahmed Elreedy;A. Tawfik
厌氧消化在处理富含蛋白质的废水(如明胶)中的工业应用前景看好，然而，释放过量的氨气等对产甲烷菌的抑制作用造成了局限性。本研究探讨了连续暗发酵和光发酵在废水处理和同步生物制氢(作为能源)方面的潜力。为此，引入了一种新的结构，即暗光圆形折流板反应器，并在常温(21 ± 10 °C)下运行。该反应器由四个相同的隔室组成，在最后两个隔室即C1-C2(暗)和C3-C4(照片)上安装了荧光灯管。考察了主要运行参数(即初始pH值为5.5和6.5时水力停留时间分别为6、12和24 h)的长期影响。在水力停留时间为24 h、初始pH为6.5时，最大产氢率可达0.4kgCOD/gCOD，COD值为82%，有机氮去除率为95%。增加水力停留时间可以在常温下保持反应器的效率。将初始pH降低到5.5会恶化C1和C2处的暗处理，导致局部HY和氨化效率降低。进一步证实了光发酵的HY较高，因为蛋白质的水解主要是在暗发酵中完成的。在所有试验条件下，剩余游离氨(<；0.36 mg/L)均低于光合细菌的抑制限度。微生物群落分析揭示了紫色非硫细菌家族红螺菌C3的发育。通过考虑基建成本、年成本(即闪电、抽水、营养物质和气体净化)和收入(即生物氢能和去除附加值)，对DP-CBR的经济效益进行了评估。总体而言，DP-CBR性能的技术经济评估强调了其在处理富含明胶的废水时在负担得起的有机物去除和生物能源回收方面的可行性。
The industrial application of anaerobic digestion to treat protein-rich wastewater (e.g., gelatin) is promising; however, inhibitory effects such as released excess ammonia on methanogens causes limitations. This study investigated the potential of sequential dark and photo-fermentation for wastewater treatment and simultaneous bio-hydrogen production (as energy source). To this end, a new configuration, namely dark-photo circular baffled reactor (DP-CBR) was introduced and operated at ambient temperature (21 ± 10 °C). The reactor was composed of four identical compartments, where fluorescent tubes were installed to the last two compartments, i.e., C1-C2 (dark) and C3-C4 (photo). The long-term impact of main operational parameters (i.e., hydraulic retention time [HRT] of 6, 12 and 24 h at initial pH of 5.5 and 6.5) was assessed. Maximum hydrogen yield (HY) of 0.4 L/gCOD, COD removal of 82%, and organic-N removal of 95% were obtained at HRT of 24 h and initial pH of 6.5. Increasing HRT was found to maintain the reactor efficiency at ambient temperature. Lowering initial pH to 5.5 deteriorated the dark-treatment at C1 and C2, resulting in lower local HY and ammonification efficiency. Further, the results confirmed that higher HY was achieved in the photo-fermentation, as the protein hydrolysis was mainly achieved in the dark-fermentation. The residual free ammonia (<0.36 mg/L), at all examined conditions, was below the inhibition limit of photosynthetic bacteria. The microbial community analysis revealed the development of purple non-sulfur bacterial familyRhodospirillaceaeat C3. The economic efficiency of DP-CBR was also evaluated by considering the capital cost, annual costs (i.e., lightning, pumping, nutrients, and gas purification), and revenues (i.e., bio-hydrogen energy and removal add-value). Overall, the techno-economic assessment of DP-CBR performance emphasizes its feasibility in affordable removal of organics and bioenergy recovery when dealing with gelatin-rich wastewater.