水稻与棉花秸秆不同预处理厌氧发酵产沼气

以猪粪为接种物,以棉花秸秆和水稻秸秆为发酵原料,分别对秸秆进行稀碱法预处理和稀碱法与超声波联合预处理,在发酵温度为(37±1)℃的条件下进行厌氧发酵产沼气的研究。结果表明,以联合预处理的秸秆为发酵原料,厌氧发酵的各项指标均比以稀碱预处理秸秆发酵的效果好,其中累积产气量和沼气中甲烷含量分别提高35.23%和2.4%,发酵后TS、VS含量相对减少2.6%～10.94%,发酵液代谢产物中的有机酸丙酮酸、乙酸和柠檬酸含量相对减少23.9%～25.9%、20.24%～24.53%和41.08%～45.91%。     

微量元素对牛粪低温厌氧发酵的影响

为考察较低温度(<17℃)条件下添加微量金属元素对厌氧发酵产气量的影响,在发酵底物TS(含固率)为10%下采用10 L玻璃瓶作反应器,以牛粪为原料,向厌氧生物反应器中分别添加MnSO4、FeSO4·7H2O、电解锰渣,分析了厌氧消化系统运行过程中的产气量、COD(化学需氧量)和pH的变化。结果表明,锰元素能促进低温下牛粪的厌氧发酵,加速反应启动。当添加6 g MnSO4、100 g电解锰渣时,单位质量VS产气率分别为0.26 mL/g和0.64 mL/g,添加6 g FeSO4·7H2O与空白对照组均未见明显产气。     

Kinetics study of fermentative hydrogen production from liquid swine manure supplemented with glucose under controlled pH

Kinetics of H₂ production from liquid swine manure supplemented with glucose by mixed anaerobic cultures was investigated using batch experiments under four different pH conditions (4.4, 5.0, 5.6, and uncontrolled). The temperature for the experiments was controlled at 37 ± 1°C and the length of experiments varied between 50 and 120 hours, depending upon the time needed for completion of each individual experiment. The modified Gompertz model was evaluated for its suitability for describing the H₂ production potential, H₂ production rate, and substrate consumption rate for all the experiments. The results showed that the Gompertz model could adequately fit the experimental results. The effect of pH was significant on all kinetic parameters for H₂ production including yield, production rate and lag time, and the substrate utilization rate. The optimal pH was found to be 5.0, at which a maximum H₂ production rate (0.64 L H₂/h) was obtained, and deviation from the optimal pH could result in substantial reductions in H₂ production rate (0.32 L H₂/h for pH 4.0 and 0.43 L H₂/h for pH 5.6). The results also showed that if pH was not controlled for the batch fermentation process, the substrate utilization efficiency could steeply decrease from 98.8% to 33.7%.     

响应面法和神经网络优化Acinetobactersp．DNS32发酵基质

为了提高阿特拉津降解菌Acinetobactersp．DNS32的产量,分别采用响应曲面法和基于人工神经网络的遗传算法对阿特拉津降解菌DNS32发酵培养基中3个重要基质成分（玉米粉、豆饼粉、K：HPO。）进行优化研究。响应曲面法确定3种成分的含量为玉米粉39．494g／L,豆饼粉25．638g／L和K。HPO。3．265g／L时,预测发酵活菌最大生物量为7．079×10^8CFU／mL,实测量为7．194×10^8CFU／mL;人工神经网络结合遗传算法优化确定3种主要成分含量为玉米粉为39．650g／L,豆饼粉为25．500g／L,K2HPO4为2．624g／L时,预测最大值为7．199×10^8CFU／mL,实测量为7．244×10。CFU／mL;最终确定培养基配方：玉米粉为39．650g／L,豆饼粉为25．500g／L,K2HPO4为2．624g／L,CaCO3为3．000g／L,MgSO4·7H2O和NaCl均为0．200g／L;优化后阿特拉津降解菌DNS32发酵生物量比优化前提高了36．6％。结果表明,在阿特拉津降解菌DNS32发酵培养基组分优化方面,响应面法和基于人工神经网络的遗传算法都是可行的,基于人工神经网络的遗传算法具有更好的拟合度和预测准确度。     

腐熟蓝藻与厌氧污泥混合厌氧发酵特性

采用批次小试实验对不同腐熟程度的蓝藻进行厌氧发酵产沼气实验研究。结果表明,新鲜蓝藻在30-35℃时腐熟7 d后,可在35℃的厌氧温度下获得最高的产气速率和246 mL/g COD的产气量,产气潜力为354 mL/g（VS）。厌氧反应15 d后,累计产气量、COD和VFA浓度趋于稳定。淀粉酶和脱氢酶的活性在厌氧反应初期受到抑制,蛋白酶活性和辅酶F420浓度在厌氧系统中逐渐增加,分别在第6天达到27.66μmol/（g VS·min）和第15天达到0.62μmol/g（VS）。15-18d是腐熟蓝藻适宜的中温厌氧发酵时间,少于以新鲜蓝藻为基质的厌氧消化时间。蓝藻腐熟过程促进了厌氧反应,腐熟7 d的蓝藻厌氧系统具有更高的微生物活性和产甲烷能力。     

粪大肠菌群多管发酵测定法的改进研究

对地表水和废水中粪大肠菌群目前通用的多管发酵检测方法进行优化。将水样接种至乳糖蛋白胨培养液后,在44.5℃±0.5℃培养箱中培养24h记录结果,并与优化前的方法进行对比。结果表明,改进后的方法在时间上比改进前节省了约24~48小时,但两者在结果上无统计学意义的差别。多管发酵改进法可以用于地表水和废水中粪大肠菌群的检测。     

秸秆生产燃料乙醇的研究进展

秸秆的化学成分复杂,主要由纤维素、半纤维素和木质素三大部分组成。经过预处理、发酵和脱水可生成燃料乙醇,秸秆乙醇化技术已经备受关注。针对预处理、发酵和脱水3个过程的多种化学或生物技术的研究进展进行了分析,同时也指出其不足。秸秆预处理中的超临界技术虽然设备制造成本高,但在秸秆资源化中与传统技术相比显示了独特的优势,具有反应迅速、无需催化剂、无产物抑制等优点。     

pH值调控柠檬酸污泥厌氧发酵产酸及碳源潜力研究

以柠檬酸废水厌氧颗粒污泥为接种物,在不同pH值调控条件下开展柠檬酸生产废水剩余活性污泥厌氧发酵产酸研究.通过对发酵液挥发性脂肪酸(VFAs)、有机质、氮磷和污泥脱水性能的分析,探讨了柠檬酸污泥厌氧产酸机制.结果表明,pH≥10的碱性条件更有利于有机质的溶出从而促进VFAs的产生.三维荧光光谱分析发现在恒定pH值下腐殖酸(HA)和富里酸(FA)会大量溶出降低VFAs的产量.初始pH=10是柠檬酸污泥厌氧产酸的最佳p H值,发酵4d的VFAs浓度最高达(6681.47±126.82)mgCOD/L,是文献报道中市政污泥产酸量的近2倍,其中乙酸占比49.8%,发酵后产酸功能菌Chloroflexi、Bacteroidota的相对丰度分别由初始的9.52%、10.87%增至16.84%、14.39%,污泥归一化毛细吸水时间(nCST)为(11.34±0.27)s·L/g,脱水性能良好,发酵液TP浓度为(20.45±0.33) mg/L.研究表明,利用柠檬酸剩余活性污泥碱性厌氧发酵产酸作为污水处理过程中的外加碳源具有较大潜力.     

Penicillin fermentation residue biochar as a high-performance electrode for membrane capacitive deionization

● We have provided an activated method to remove the toxicity of antibiotic residue. ● PFRB can greatly improve the salt adsorption capacity of MCDI. ● The hierarchical porous and abundant O/N-doped played the key role for the high-capacity desalination. ● A new field of reuse of penicillin fermentation residue has been developed. Membrane capacitive deionization (MCDI) is an efficient desalination technology for brine. Penicillin fermentation residue biochar (PFRB) possesses a hierarchical porous and O/N-doped structure which could serve as a high-capacity desalination electrode in the MCDI system. Under optimal conditions (electrode weight, voltage, and concentration) and a carbonization temperature of 700 °C, the maximum salt adsorption capacity of the electrode can reach 26.4 mg/g, which is higher than that of most carbon electrodes. Furthermore, the electrochemical properties of the PFRB electrode were characterized through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) with a maximum specific capacitance of 212.18 F/g. Finally, biotoxicity tests have showed that PFRB was non-biotoxin against luminescent bacteria and the MCDI system with the PFRB electrode remained stable even after 27 adsorption–desorption cycles. This study provides a novel way to recycle penicillin residue and an electrode that can achieve excellent desalination.     

Phosphorus recovery from biogas fermentation liquid by Ca–Mg loaded biochar

Shortage in phosphorus (P) resources and P wastewater pollution is considered as a serious problem worldwide. The application of modified biochar for P recovery from wastewater and reuse of recovered P as agricultural fertilizer is a preferred process. This work aims to develop a calcium and magnesium loaded biochar (Ca–Mg/biochar) application for P recovery from biogas fermentation liquid. The physico-chemical characterization, adsorption efficiency, adsorption selectivity, and postsorption availability of Ca-Mg/biochar were investigated. The synthesized Ca–Mg/biochar was rich in organic functional groups and in CaO and MgO nanoparticles. With the increase in synthesis temperature, the yield decreased, C content increased, H content decreased, N content remained the same basically, and BET surface area increased. The P adsorption of Ca–Mg/biochar could be accelerated by nano-CaO and nano-MgO particles and reached equilibrium after 360 min. The process was endothermic, spontaneous, and showed an increase in the disorder of the solid–liquid interface. Moreover, it could be fitted by the Freundlich model. The maximum P adsorption amounts were 294.22, 315.33, and 326.63 mg/g. The P adsorption selectivity of Ca–Mg/biochar could not be significantly influenced by the typical pH level of biogas fermentation liquid. The nano-CaO and nano-MgO particles of Ca–Mg/biochar could reduce the negative interaction effects of coexisting ions. The P releasing amounts of postsorption Ca–Mg/biochar were in the order of Ca–Mg/B600 > Ca–Mg/B450 > Ca–Mg/B300. Results revealed that postsorption Ca–Mg/biochar can continually release P and is more suitable for an acid environment.